Bacteriology Test 2

Front 1

Bacterial req for growth

Back 1

1. oxygen - or absence of
2. energy
3. nutrients
4. optimal temperature
5. optimal pH

Front 2

Obligate aerobes

Back 2

- grow in presence of oxygen
- no fermentation
- employ oxidative phosphorylation

Front 3

obligate anaerobes

Back 3

- no oxidative phosphorylation
- fermentation
- killed by oxygen
- lack certain enzymes
- superoxide dismutase (O2- + 2H+ --> H2O2
- catalase ( H2O2 --> H2O + O2)
- peroxidase (H2O2 + NADH + H+ --> H2O + NAD)

killed by oxygen b/c lack those enzymes that detoxify H2O2 and oxygen free radicals (superoxide) - these are produced during metabolism in the presence of oxygen

Front 4

Aerotolerant anaerobes

Back 4

respire anaerobically
not killed by oxygen

Front 5

Facultative anaerobes

Back 5

- aerobic respiration
- fermentation
- survive in oxygen

Front 6

microaerophilic bacteria

Back 6

- grow in low oxygen
- killed in high oxygen

Front 7

mesophiles

Back 7

human body temp
- pathogens
- ooportunists

Front 8

psychrophile

Back 8

survive best at close to freezing

Front 9

thermophile

Back 9

survive best at close to boiling

Front 10

pH and growth

Back 10

many grow best at neutral pH

some can survive/grow in
- acid
- alkali

Front 11

Nutrient requirements

Back 11

1. carbon
2. nitrogen
3. phosphorus
4. sulfur
5. metal ions (iron)

Front 12

siderophores

Back 12

secreted by bacteria
- enterobactin
- myobactin
- sml molecule
- binds iron
- then internalized via receptors by the bacterial cell

- transferrin in humans bind iron - so bacteria that compete for this iron are poor pathogens

Front 13

Measuring bacteria mass in liquid cultures of bacteria

Back 13

1. Turbidity - how cloudy a liquid culture is
- total bacteria [live or dead]
- quantitated w/a spectrophotometer

2. number of viable cells in a culture
- assessed by counting the number of colonies that grow after streaking a known volume on a plate
- plate counting of colony forming units

Front 14

growth curve

Back 14

plotting the:
- log of turbidity or the
- number of living cells vs time

lag phase - bacteria are adapting to media - little -> no growth

log phase - growth is fast - logarithmic

stationary phase - bacteria stop growing

death phase/autolysis - nutrient supply is exhausted - bacteria start to die or autolyse = decrease in turbidity

death in CFU
autolysis in turbidity

Front 15

generation time

Back 15

time req for bacterial mass to double

ex - 100 bacteria present at time 0
- if generation time is 2hr what is mass at 8 hr?
100x 2^4

Front 16

sugar catabolism

Back 16

1. glycolysis
2. pentose phosphate pathway
3.Entner Doudoroff Pathway

Front 17

glycolysis

Back 17

- AKA = embeden meyerhof Parnas pathway
- most common pathway bacteria
- series enzymatic rxnconvert sugar -> pyruvate generating ATP and NADH (how chem E for biosyn purposes is stored)

Front 18

pentose phosphate pathway

Back 18

AKA: hexose monophosphate shunt

NADPH generated

Front 19

Entner Doudoroff Pathway

Back 19

few bacterial species
not in animals

Front 20

anaerobic respiration

Back 20

glycolysis and fermentation

in later stages NADH converted back to NAD by losing a H which is added to pyruvate

depending on the bacterial species a variety of metabolic end-products can be produced
(short chain alcohols or FA - lactic acid or ethanol C2-C4)

ATP is increased

Front 21

Aerobic respiration

Back 21

glycolysis + krebs cycle

pyruvate fully broken down to CO2 and Nad converted to NADH

NADH generated from 2 sources (glycolysis and krebs cycle)

oxidative phosphorylation converts excess NADH back to NAD and in the process produces more ATP

ubiquinones and cytochromes are components of the ETC involved in this NADH-> NAD process

conversion of O2 -> H2O final step in process

Front 22

krebs cycle

Back 22

C4-C6 intermediate compounds

Pyruvate C3 -> 3CO2

NAD -> NADH

pyruvate - CO2 = Acetate C2
Acetate + Oxaloacetate C4 = citrate C6 -> isocitrate
Isocitrate - CO2, NADH = alpha ketoglutarate
alpha ketoglutarate - Co2, NADH = succinate -> fumarate -> malate -> oxaloacetate

oxaloacetate can go to citrate and back or to aspartic acid (AA) replenishing biosyn

if sugars are the sole C source removing Kreb int = shut down cycle

fatty acids as a sole carbon source
- FA-> acetate + oxaloacetate
- if sole c source no kreb cycle int can be removed w/o shutting it down

Front 23

Oxidative phosphorylation

Back 23

O2 => H2O (oxidative)

NADH -> NAD

ADP -> ATP (phosphorylation)

via ETC and ubiquinones/cytochrome intermediates

Front 24

Glyoxylate cycle

Back 24

some bacteria use instead of krebs

C4->C6

2 enzymatic steps in which CO2 removed from int is by pased

C6 int -> 2 C4 compounds
for every acetyl group an additional cycle int can be produced

not found in animals since preformed FA are utilized

Front 25

Cell envelope

Back 25

cell membrane + cell wall (+outer membrane)

cell wall
- peptidoglycan
- attached structures

most fall into one of 2 categories
- gram neg or gram positive
other types found in few bacterial species - neither gram neg or gram positive

Front 26

gram positive

Back 26

peptidoglycan + plasma membrane = cell envelope

teichoic acid
- bound covalently to the peptidoglycan
- backbone = polymers of ribitol phosphate or glycerol phosphate)
- can direct autolytic enxymes to sites of peptidoglycan digestion (autolysis) - needed to insert sections of cell wall for growth and division

Teichuronic acid
- binds to PG
- polymer of glucuronic acid cont polysaccharides
- syn under phosphate limiting cond = no phosphorus
- neutral polysaccarides are sometimes present instead

Lipoteichoic acid - primarily assoc w/cell membrane
- bind autolysisns keeping them awak from cell wall until needed for biosyn

teichoic and teichuronic acids
- metal ion uptake
- direct autolytic enzymes

Front 27

gram negative

Back 27

cell envelope
- outer membrane
- peptodoglycan
- periplasmic space
- plasma membrane

Braun lipoprotein
- covalently linked to thin peptidoglycan
- binds outer mem to cell wall

Outer membrane
-lipopolysaccharides LPS
- phospholipids
- proteins -> porins - allows passage of sml hydrophilic nut - sugars

Front 28

peptidoglycan

Back 28

- single macromolecule - bag shapped highly cross linked
- provides rigidity
- surrounds cell membrane

- consists of :
1. glycan = polysaccharide - backbone consisting of
a. N-acetyl muramic acid
b. N- acetyl -glucosamine
d. peptide chains containing
I. D and L - amino acids
II. diaminopimelic acid - in some cases

side chains are connected directly by peptide bond or by peptide bridges (vary in structure) - can contain same AA as side chain or diff ones

Muramic acid, D- AA, and diaminopimelic acid are not syn by mammals
PG found in all eubacteria except chlamydia and mycoplasma

Front 29

lipopolysaccharide

Back 29

imp to bact cell b/c helps provide permeability barier

3 regions:
O antigen - hihgly variable
core - middle containng several sugars - heptoses and ketodeoxyoctonic acid - not found commonly in nature

- inner lipid A - containing Beta hydroxy FA (also uncommon in natue) and glucosamine disaccharide

endotoxin activity

Front 30

acid fast cell envelope

Back 30

1. mycobacteria
2. nocardia
3. corynebacteria

resembles gram positive bacteria w/polysaccharide covalently bound to PG

- mycolic acids - long, branch chained FA - covalently linked to polysaccharide

- other mycolic acid cont cmpds and complex lipids form thick waxy membranous layer outside peptidoglycan (oter membrane)

Front 31

peptidoglycan syn

Back 31

1. muramyl pentapeptde attached to uridine diphosphate (UDP) = precursor subunit = syn in cytoplasm

2. passed to cell membrane

3. subunit moved enzymatically from nt to lipid carrier ( undecaprenol/bactoprenol)

4, built into completed subunit - disaccharide pentapeptide w/attached bridge peptides (side chains doesn't req ribosome for syn)

5. completed subunit exported to cell wall

6. release of the monomer - undecaprenol is recirculated in the cell membrane and used again

7. glycan backbone of existing cell wall enzymatically broken by autolysins toallow insertion of new subunit
- ifoveractive cell wall becomes degraded and high osmotic pressure of cell burts the cytoplasmic membrane = autolysis

8. cross linking of peptide side chain of inserted subunit to existing chain occurs enzymatically (penicillin binding proteins)

- teichoic and teichuronic acids also syn in cell membrane on lipid carriers before transport and insertion into cell wall

Front 32

lipopolysaccharide

Back 32

syn similar to PG

lipid A assembled in cell membrane and core sugars are attached sequentially

O antigen subunits independently synsized on a lipid carrier ( undecaprenol carrier)

fully syn O ag attached to lipid A core in cell membrane before passage/insertion into outer membrane

fully syn

Front 33

endospores

Back 33

modified gram positive bbacterial cells w/unusual cell envelope

- cell membrane
- outer membrane

norm a septum forms dividing mother cell into 2 roughly equal daughter cells when they divide but when sporulation occurs cell div is unequal

larger bacterium = mother cell which envelops the daughter cell

cell membrane of daughter constitiutes the inner membrane of the spore
- cell membrane of mother forms outer membrane

PG layer is less cross linked than in most bact cells
- cont a dehydrated form of muramic acid (lactam)
- spore PG = cortex and found btw 2 membranes
- thick prot coat = bacterial spore highly resistant to chem agents

exosporium - made up of glycoproteins surrounds the coat
inside -> out
1. inner membrane
2. cortex
3. outermembrane
4. coat
5. exosporium

Front 34

Cell envelope

Back 34

cell membrane + cell wall (+outer membrane)

cell wall
- peptidoglycan
- attached structures

most fall into one of 2 categories
- gram neg or gram positive
other types found in few bacterial species - neither gram neg or gram positive

Front 35

gram positive

Back 35

peptidoglycan + plasma membrane = cell envelope

teichoic acid
- bound covalently to the peptidoglycan
- backbone = polymers of ribitol phosphate or glycerol phosphate)
- can direct autolytic enxymes to sites of peptidoglycan digestion (autolysis) - needed to insert sections of cell wall for growth and division

Teichuronic acid
- binds to PG
- polymer of glucuronic acid cont polysaccharides
- syn under phosphate limiting cond = no phosphorus
- neutral polysaccarides are sometimes present instead

Lipoteichoic acid - primarily assoc w/cell membrane
- bind autolysisns keeping them awak from cell wall until needed for biosyn

teichoic and teichuronic acids
- metal ion uptake
- direct autolytic enzymes

Front 36

gram negative

Back 36

cell envelope
- outer membrane
- peptodoglycan
- periplasmic space
- plasma membrane

Braun lipoprotein
- covalently linked to thin peptidoglycan
- binds outer mem to cell wall

Outer membrane
-lipopolysaccharides LPS
- phospholipids
- proteins -> porins - allows passage of sml hydrophilic nut - sugars

Front 37

peptidoglycan

Back 37

- single macromolecule - bag shapped highly cross linked
- provides rigidity
- surrounds cell membrane

- consists of :
1. glycan = polysaccharide - backbone consisting of
a. N-acetyl muramic acid
b. N- acetyl -glucosamine
d. peptide chains containing
I. D and L - amino acids
II. diaminopimelic acid - in some cases

side chains are connected directly by peptide bond or by peptide bridges (vary in structure) - can contain same AA as side chain or diff ones

Muramic acid, D- AA, and diaminopimelic acid are not syn by mammals
PG found in all eubacteria except chlamydia and mycoplasma

Front 38

lipopolysaccharide

Back 38

imp to bact cell b/c helps provide permeability barier

3 regions:
O antigen - hihgly variable
core - middle containng several sugars - heptoses and ketodeoxyoctonic acid - not found commonly in nature

- inner lipid A - containing Beta hydroxy FA (also uncommon in natue) and glucosamine disaccharide

endotoxin activity

Front 39

acid fast cell envelope

Back 39

1. mycobacteria
2. nocardia
3. corynebacteria

resembles gram positive bacteria w/polysaccharide covalently bound to PG

- mycolic acids - long, branch chained FA - covalently linked to polysaccharide

- other mycolic acid cont cmpds and complex lipids form thick waxy membranous layer outside peptidoglycan (oter membrane)

Front 40

peptidoglycan syn

Back 40

1. muramyl pentapeptde attached to uridine diphosphate (UDP) = precursor subunit = syn in cytoplasm

2. passed to cell membrane

3. subunit moved enzymatically from nt to lipid carrier ( undecaprenol/bactoprenol)

4, built into completed subunit - disaccharide pentapeptide w/attached bridge peptides (side chains doesn't req ribosome for syn)

5. completed subunit exported to cell wall

6. release of the monomer - undecaprenol is recirculated in the cell membrane and used again

7. glycan backbone of existing cell wall enzymatically broken by autolysins toallow insertion of new subunit
- ifoveractive cell wall becomes degraded and high osmotic pressure of cell burts the cytoplasmic membrane = autolysis

8. cross linking of peptide side chain of inserted subunit to existing chain occurs enzymatically (penicillin binding proteins)

- teichoic and teichuronic acids also syn in cell membrane on lipid carriers before transport and insertion into cell wall

Front 41

lipopolysaccharide

Back 41

syn similar to PG

lipid A assembled in cell membrane and core sugars are attached sequentially

O antigen subunits independently synsized on a lipid carrier ( undecaprenol carrier)

fully syn O ag attached to lipid A core in cell membrane before passage/insertion into outer membrane

fully syn

Front 42

endospores

Back 42

modified gram positive bbacterial cells w/unusual cell envelope

- cell membrane
- outer membrane

norm a septum forms dividing mother cell into 2 roughly equal daughter cells when they divide but when sporulation occurs cell div is unequal

larger bacterium = mother cell which envelops the daughter cell

cell membrane of daughter constitiutes the inner membrane of the spore
- cell membrane of mother forms outer membrane

PG layer is less cross linked than in most bact cells
- cont a dehydrated form of muramic acid (lactam)
- spore PG = cortex and found btw 2 membranes
- thick prot coat = bacterial spore highly resistant to chem agents

exosporium - made up of glycoproteins surrounds the coat
inside -> out
1. inner membrane
2. cortex
3. outermembrane
4. coat
5. exosporium

Front 43

sterilization

Back 43

all killed
non-selective

1. autoclaving - 121 degree C heat/steam pressure

2. ethylene oxide
- non heat resistant
- usually eq
- being replaced by H2O2/free radicals

3. ultra-violet light
- surfaces (operating rooms)
- not totally effective

4. gamma radiation
- mainly food industry

5. membrane filters
- pores that trap bacteria but allow drugs and sml chem to pass through
- used for delicate solutions
- air treated in rooms w/ HEPA filters

Front 44

disinfectants

Back 44

liquids that kill bacteria
- phenol based or quarternary ammonium cmpds
- too toxic for skin surfaces

Front 45

antiseptics

Back 45

topical - skin
- iodine or 70% alcohol
- reduce bacterial lode

Front 46

antibiotics

Back 46

selectively toxic for bacteria
- bactericidal - killing - inhibit cell wall biosyn = burst
- bacteriostatic - growth inhibition

minimize harm to pt

damage structures
- present in bacteria thats not present in host

work together w/the IS

Front 47

minimial inhibitory concentration

Back 47

lowest level of antibiotic to stop growth in liquid

zone of inhibition around a disk impregnated w/antibiotic

Front 48

inhibition of the synthesis of PG

Back 48

autolysis of cell occurs w/o syn of PG b/c of high osmotic pressure inside the cell - burst inner or outer membrane
- abx = bactericidal

Front 49

Cycloserine

Back 49

analine analog abx

- inhibits conversion of L-ala -> D- ala
- inhibits formation of D-ala-D-ala in cytoplasm

-the terminal 2 AA of peptide side chain of PG is 2 D-ala
so syn of of PG doesn't occur

mainly to tx TB

Front 50

Bacitracin

Back 50

PG is attached to undecaprenol through a second phosphate group
- subunit-diphosphate-undecaprenol complex passed across the cytoplasmic membrane
- after peptigolycan leaves carrier the terminal phosphate on undecaprenol is removed

- bacitraicin inhibits this dephosphorylation
- absence of free carrier no more PG can be passed = biosyn stops

Front 51

Vancomycin

Back 51

- binds D-ala-D-ala
- inhibits crosslinking

- during crosslinging new PG to polymer D-ala is enzymatically excised from end of preexisting peptide side chain - allowing it to be able to cross link to recently syn PG

Front 52

Beta lactam antibiotics

Back 52

1. penicillins (ampicillin_
2. cephalosporins/cephamycins
3. monobactams

- bind to and inhibit enzmes (penicillin binding protiens) involved in the transpeptidatinon - cross linking
- a region of penicillin is an analog of the D-ala-D-alaincluding the peptide bond

in common:
- 4 membered lactam ring

penicillins have additional 5 membered ring attached

cephalosporins (and cephamycins - ring O replaces S) - have an extra 6 membered ring

monobactams - just the lactam ring

Front 53

chem modifications change biol activity of beta lactam rings

Back 53

early lactam antibiotics - inactive against gram negative- b/c do not penetrate outer membrane

cephalosporins and newer penicillins are active against the gram neg bacterteria

due to chem side chains

other penicillins have lower elimination rates from pts - decreasing freq of admin

Front 54

resistance mechanisms

Back 54

produce beta lactamase (penicillinase) action - breaks the lactam ring between C-N
= destroys abx

- Clavulinic acid, a beta lactam - binds strongly to beta lactamases = limited potency
- used in combo w/certain penicillins allowing their use against otherwise resistant bacteria

- modified structure of penicillin binding protiens - abx don't bind efficienty

- modified porins in gram negative bacteria which penicillins pass through

- one of the terminal AA of PG may be replaced = vancomycin won't bind

Front 55

Polymyxin B

Back 55

binds lipid A portion of LPS and phospholipids
- preferentially to lipid A

- disrupts outer mem of gram negative bacteria
- toxic to human cells - can also lyse eukaryotic membranse == limited clinical use

Front 56

daptomycin

Back 56

causes depolarization of bacterial cell membrane

Front 57

anti- TB drugs

Back 57

Isoniazid and ethionamide
- chem related
- blocks mycolic acid syn

ethambutol
- blocks arabinogalactan syn

cycloserine

Front 58

antibiotics that disrupt cell wall syn

Back 58

1. beta lactams
2. vancomycin
3. isoniazid
4. ethambutol
5. cycloserine
6. ethionamide
7. bacitracin
8. polymyxin

Front 59

antibiotics that disrupt DNA replication

Back 59

1. quinolones
2. metronidazole
3. clofozimine

Front 60

abx that disrupt RNA syn

Back 60

1.rifampin
2. rifabutin

Front 61

Abx that disrupt prot syn (50 S ribosome)

Back 61

1. chloramphenicol
2. macrolides
3. clindomycin
4. linezolid
5. quinupristin-dalfopristin

Front 62

abx that disrupt prot syn (30 S ribosomes)

Back 62

1. aminoglycosides
2. tetracyclines

Front 63

abx that are antimetabolites - disrupt metab

Back 63

1. sulfonamides
2. dapsone
3.trimethoprim
4. para-aminosalicylic acid

Front 64

selectivity

Back 64

clinically effective abx exhibit selectivity toward bacteria -not host

high selectivity = not toxic abx but can have side effects

Front 65

Therapeutic index

Back 65

toxic dose/effective dose

higher the therapeutic index the better the antibiotic

Front 66

bacteriostatic

Back 66

-reversibly inhibit growth
- duration of tx sufficient for host defenses to eradicate infection

better therapeutic index than bactericidal
- used when org is resistant to bactericidal abx
- use when prot toxin mediates dx - bacteriostatic prot syn inhibitor to immediately block syn of toxin

Front 67

bactericidal

Back 67

kill bacteria

usually abx of choice for infections in sites such as endocardium or meninges where host defenses are ineffective

Front 68

abx susceptibility testing

Back 68

1. bacteriostatic abx
- minimum inhibitory conc
- lowest conc that results in inhibition of visible growth - colonies on plate or turbidity of liquid culture

2. bactericidal abx
- min bactericidal conc (MBC)
- lowest conc that kills 99.9% of original inoculum

for abx to be effective the MIC or MBC must be achieved at site of infection
- pharmacological abs and distribution influences:
a. dose
b. route
c. freq of administration

Front 69

disk diffusion test

Back 69

1. bacterial isolate inoculated uniformly on surface of agar plate

2. filter disk impregnated w/ststandard amt ofabx applied to surfface - abx is allowed to diffuse into medium

3. after incubation - zones of inhibition of bacterial growth around disk
- size of xone is dependent on the diffusion rate of abx. the degree of sensitivity of microorg, and growth rate of bacterium

inversley related to MIC

standard zones of inhibition have been est for each abx
- if the zone of inhibition is equal to or greater than the standard the org is considered to be sensitive to the abx
- if the zone of inhibition is less than the standard - org is resistant

susceptible, moderately susceptible, intermediae susceptible

Front 70

combination therapy

Back 70

- prevent emergence of resistant strains
- temp tx until diagnosis is made
- take advantage of abx synergism
- penicillins and aminoglycosides = cell wall syn innhibited - allows aminoglycosides to enter bact and inhibit prot syn
- Caution antibiotic antagonism
- penicillins and bacteriostatic abx - cell wall syn not occuring ad cells aren't growing
- when one abx interferes w/effect of other one- usually one w/least effect does interferrin

Front 71

antibiotics vs chemotherapeutic agents

Back 71

abx - naturally occuring materials

cheomtherapeutic agents - syn in lab-most abx are now syn and are actually chemotherapeutic agents

all called antimicrobic or antimicrobial agent

Front 72

abx that inhibit initiation

Back 72

1. streptinomycininhibit the 30S subunit binding the mRNA, f-tRNA, and releasing initiation factor 3

2. tetracycline blocks f-tRNA from binding to A site

3. aminoglycosides - blocks 50S from binding w/ the 30S initiation complex and release of initiation factors 1 and 2and GDP+Pi

chloramphenicol and macrolides also block the 50 S ribosome

Front 73

abx that block elongation of protein syn

Back 73

chloramphenicol blocks the transfer of aa in p site to aa on tRNA in A site

erythromycin blocks GTP from coming in and moving the tRNA from A site to P site

fusidic acid - blocks the recirculation of G-GDP+ Pi -> GDP + G whrere it then goes on to bind anoter GTP

Front 74

clinical resistance

Back 74

occurs when the MIC of the drug for a particular strain of bacteria exceeds that which is capable of being achieved w/safety in vivo

Front 75

resistance to an antimicrobial arises by

Back 75

1. mutation in gene that det. sensitivity/resistance to the agent
2. acquisition of extrachromosomal DNA plasmid carrying a resistance gene
- resistance that appears after introduction of antimicrobial agent int o the enviro = results from a selective process

agent selects for survival of those strains possessing a resistance gene

- dev in a single step or from accumulation of multiple mut

Front 76

cross resistance

Back 76

single mech confers resistance to multiple antimicrobial agents

closely related abx are rendered ineffective

Front 77

multiple resistance

Back 77

multiple mechanism involved

unrelated antimicrobial agemts
- bacteria acquire mult plasmids

Front 78

abx that block elongation of protein syn

Back 78

chloramphenicol blocks the transfer of aa in p site to aa on tRNA in A site

erythromycin blocks GTP from coming in and moving the tRNA from A site to P site

fusidic acid - blocks the recirculation of G-GDP+ Pi -> GDP + G whrere it then goes on to bind anoter GTP

Front 79

clinical resistance

Back 79

occurs when the MIC of the drug for a particular strain of bacteria exceeds that which is capable of being achieved w/safety in vivo

Front 80

resistance to an antimicrobial arises by

Back 80

1. mutation in gene that det. sensitivity/resistance to the agent
2. acquisition of extrachromosomal DNA plasmid carrying a resistance gene
- resistance that appears after introduction of antimicrobial agent int o the enviro = results from a selective process

agent selects for survival of those strains possessing a resistance gene

- dev in a single step or from accumulation of multiple mut

Front 81

cross resistance

Back 81

single mech confers resistance to multiple antimicrobial agents

closely related abx are rendered ineffective

Front 82

multiple resistance

Back 82

multiple mechanism involved

unrelated antimicrobial agemts
- bacteria acquire mult plasmids

Front 83

Mechanisms of resistance

Back 83

1. Altered permeability
- altered influx -> mutation in a transporter necessary to import antibiotic can lead to resistance
- altered efflux - acquire transporter gene that will pump the antibiotic out (tetracycline)

2, inactivation of the antimicrobial agent -> product of enzyme that is capable of inactivating the antimicrobial agent
- Beta- lactamase
- chloramphenicol acetyl transferase

3. mutation in the target site
- penicillin binding proteins - penicillin)
- RNA polymerase (rifampin)
- 30S ribosome (streptomycin) - ribosome not covered w/prot - good portion ofRNA

4. replacement of a sensitive pathway - acquisition of a new enzyme to replace the sensitive one
= sulfonamides, trimethoprim

Front 84

protein synthesis inhibitors characteristics

Back 84

mostly bacteriostatic

selectivity due to differences in prokaryotic and eukaryotic ribosomes

some toxicity - 70S ribosomes

eukaryotic mitochondria

Front 85

prokaryotic ribosomes

eukaryotic ribosomes

Back 85

prokaryotes:
5S
235S
16S

eukaryotes:
5S
28S
5.95S
18S

Front 86

Aminoglycosides

Back 86

Only bactericidal protein synthesis inhibitor
1. STREPTOMYCIN
2. kanamycin, getamincin, tobramycin, amikacin, netilmicin,neomycin

mode of action - irreversibly binds 16S subunitand freezes it in the 30S initiation complex w/mRNA and tRNA and prevents initiation of translation
- increasdes the affinity of the A site for tRNA regardless of the anticodon specificity
- includes misreading of the mRNA for proteins already being synthesized
- destabilizes microbial membranes

spectrum of activity
- many gram neg and some gram positive
- not useful for anaerobic bacteria or in anaerobic environments (oxygen req for uptake of antibiotic
- not useful for intracellular bacteria

resistance
- enzymatic modification of antibiotic is most common
- also transport or efflux and modification of target

synergy -
- synergize w/beta lactam which inhibit cell wall syn and inc the permeability of the membrane to aminoglucosidees

Front 87

tetracyclines

Back 87

bacteriostatic
1. TETRACYCLINE
- minocycline, doxycycline

MODE OF ACTION
- tetracyclines reversibly bind the 30S ribosome and inhibit binding of aminoacyl-tRNA
to accepter site on 70S subunit
SPECTRUM OF ACTIVITY
- broad spectrum with activity against gram pos and neg
- useful against intracellular bacteria like:
1. chlamydia
2. mycoplasma
3. rickettsia

RESISTANCE
- most common mode is active efflux of abx out of the cell
- also alt ribosomal target site and modification enzymes that inactivate the drug

ADVERSE EFFECTS
- elimination of norm intestinal flora resulting in increased secondary infections;
staining and impairment of the structure of bone and teeth
- DONT use in kids unless necessary

Front 88

Spectinomycin

Back 88

bacteriostatic

MODE OF ACTION
- reversibly interferes w/mRNA interaction w/30S ribosome
- structurally similiar to the aminoglycosides but doesn't cause misreading of mRNA and doesn't destabilize memprates

SPECTRUM OF ACTIVITY
- used in tx of N. gonorrhoeae
- esp penicillin-resistant strains

RESISTANCE
Rare in N. gonorrhoeae

Front 89

Chloramphenicol

Back 89

also - lincomycin, clindamycin
- bacteriostatic

MODE OF ACTION
- bind reversibly to the 50S ribosome and inhibit peptidyl transferase activity
- no new peoptide bonds formed means no elongation

SPECTRUM OF ACTIVITY
- chloramphenicol - broad range
- lincomycin and clindamycin - resticted range

RESISTANCE
- plasmid encoded acetyltransferase (cat) that renders the antibiotic incapable of binding to 50S

ADVERSE EFFECTS
chloramphenicol is toxic - can suppress prot syn in BM cells possibly producing aplastic anemia- used in life threatening situations such as tx of bacterial meningitis

Front 90

Macrolides

Back 90

bacteriostatic
ERYTHROMYCIN, clarithomycin, axithromycin

MODE OF ACTION
- inhibit translocation of the ribosome binding reversibly to 23S

SPECTRUM OF ACTIVITY
- useful for tx gram positive bacteria = in pt w/ penicilliin allergies
- mycoplasma
- chlamydia
- legionella
= most gram negative are resistant

RESISTANCE
- most common mechanism of resistance is methulation (erm) of the 23S rRNA inhibitying the binding of the drug, but the production of inactivating enzymes is also a route

Front 91

Fusidic acid

Back 91

bacteriostatic

MODE OF ACTION
- binds to elongation factor G (EF-G) and inhibits release of EF-G from EF-G/GDP complex
= can't relode EF-G w/GTP

SPECTRUM OF ACTIVITY
- gram positive cocci like staphylococcus, typicall used in creams and eyedrops

RESISTANCE
mutation of EF-G so that the drug no longer binds seen in S. aureus

Front 92

Rifampin

Back 92

riamycin, rifampicin, rifabutin, rifaximin

MODE OF ACTION
- bind to DNA dependent RNA polymerase and inhibitinitiation of mRNA syn

SPECTRUM OF ACTIVITY
- broad spectrum but used most commonly in the tx of TB and aerobic gram positive cocci

RESISTANCE
- develops rapidly through mutations of RNA polumerase

COMBINATION THERAPY
- since resistance is common, rifampin is usually used in combo therapy to tx TB

Front 93

quinolones

Back 93

NALIDIXIC ACID, CIPROFLOXACIN, oxolinic acid, norfloxacin, levofloxacin, lomefloxacin, sparfloxacin
bactericidal

MODE OF ACTION
- bind to alpha subunit of DNA gyrase (topoisomerase) and prevent negative supercoiling of DNA, causing positive supercoils to accumulate in advance of the repliccation fork
- inhibits DNA syn
inhibits DNA recombo and repair

SPECTRUM OF ACTIVITY
- gram -positive and negative bacteria

RESISTANCE
- Mutations in topo genes as well as blocking uptake

Front 94

inhibitors of folic acid synthesis

Back 94

basis of selectivity - bacteria that syntesize folic acid (humans dont)

1. p-aminobenzoic acid +
pteridine
a. Pteridine syntetase
2. dihydropteroic acid
b. dihydrofolate synthetase
3. dihydrofolic acid
c. dihydrofolate reductase
4. tetrahydrofolic acid --> thymidine, purines, methionine

req for thymidine and purine syn
sulfonamides block pteridine synthetase
trimethoprim block dihydrofolate reductase

Front 95

sulfonamides, sulfones

Back 95

MODE OF ACTION
- analogues of para-aminobenzoic acid and competitively inhibit pteridine synthetase, block the formation of dihydropteroic acid

SPECTRUM OF ACTIVITY
- broad range activity against gram positive and gram-neg bacteria; used primarily in urinary tract and Nocardia infections

RESISTANCE - due to permeability barriers

COMBO THERAPY
the sulfonamides are used in combo w/trimethoprim this combo block 2 distinct steps in folic acid metab and prevents the emergence of resistant strains

Front 96

trimethoprim

Back 96

methotrexate, pyrimethamine
bacteriostatic

MODE OF ACTION
bind to dihydrofolate reductase inhibit the formation of tetrahydrofolic acid

SPECTRUM OF ACTIVITY
broad range activity against gram positive and gram neg bacteria
- primarily used in UTI and Nocardia infections

RESISTANCE due to decreased affinity for substrates

Front 97

Combination Therapy

Back 97

these antimicrobials are used in combo w/sulfonamides
- combo blocks 2 different steps in folic acid metabolism and prevents emeregence of resistant strains

Front 98

anti mycobacterial agents

Back 98

generally used in combo w/other antimicrobials since tx is prolonged and resistance develops readily to individual agents

Front 99

para-aminosalicylic acid (PAS)

Back 99

bacteriostatic

MODE OF ACTION
similiar to sulfonamides - competitively inhibit pteridine synthetase block formation of dihydropteroic acid

SPECTRUM OF ACTIVITY
- specific for mycobacterium tuberculosis

Front 100

Dapsone

Back 100

bacteriostatic

MODE OF ACTION
- similiar to sulfonamides- competitively inhibit pteridinesynthetase, block formation of dihydropteroic acid

SPECTRUM OF ACTIVITY
- used in tx ofleprosy - mycobacterium leprae

Front 101

Isoniazid (INH)

Back 101

bacteriostatic

MODE OF ACTION
= inhibits synthethesis of mycolic acids

SPECTRUM OF ACTIVITY
- used in tx of TB

Front 102

why do we care about the exchange of genetic information between bacteria?

Back 102

1. advantageous mutation in one bacteria could be spread in a population by exchange

2. a plasmid that contains a gene for antibiotic resistance could be exchanged

3. transposons can carry drug resistance or be an agent for mutation in bacteria can also be exchanged

4. exchange of genetic information btw bacteria is the reason for multidrug resistance strains of bacteria

Front 103

Mutations in bacteria

Back 103

- induced
- spontaneous

rare mutations are expressed
- bacteria are haploid
- rapid growth rate

- selectiveadvantage enrichesfor mutants

- gene transfer occurs in bacteria

Front 104

general features of gene transfer in bacteria

Back 104

unidirectional - donor -> recipient

donor does not givve an entire chromosome = merozygotes = partial zygotes

- gene transfer can occur btw species

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transformation

Back 105

gene transfer resulting from the uptake of DNA from a donor

certain bacteria can take up DNA from enviro and then it can be incorporated into the recipients chromosome
- Bacillus
- Haemophillus
- Neisseria
- Pneumococcus

Front 106

Factors affecting transformation

Back 106

1. DNA size/state - double stranded DNA of at least 5x10^5 daltons works best
- thus transformation is sensitive to nucleases in the environment

2. competence of the recipient
- some bacteria are able to take up DNA naturally
- but only during a certain time in growth cycle when they produce a specific prot called a competence factor
- bacteria compeetence can be induced in vitro by tx w/chem CaCl2

Front 107

Steps in transformation

Back 107

1. uptake of DNA - both + and - can take up DNA

2. Legitimate/homologous/general recomb
- after the donor DNA is taken up a reciprocal recomb event occurs btw the chromosome and the donor DNA
- req homology btw donor DNA and chromosome
- req recombinate genes recA, recB, recC
- legitimate or homologous or general bc homollogy req

3. significance - transformation occurs in nature and it can lead to increased virulence
- widely used in recombinant DNA technology

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transduction

Back 108

transfer of genetic of information from a donor -> recipiet via bacteriophage

phage coat protects DNA in enviro so transduction is not affected by nucleases in the environment

mostly between members of same species - between can occur

ability of phage to mediate transduction is related to the life cycle of the phage

Front 109

bacteriophage

Back 109

phage that infects bacteria

composition
- nucleic acid - genome size - modified bases = protect from nuclease break down in host nucleic acids during phage infection
- DNA/RNA but not both
- 3-5 gene products / to over 100 gene products
- protein - protection/ infection simplest 1-2 diff/ many diff kinds

Structure T4
size 80-100nm wide and 200 nm other phages are smaller - most range from 24-200 in length
-head/capsid
= vary in size and shape = some icosahedral (20 sides)

- tail w/contracitle sheath, base plate and tail fibers
- not all have this - hollow tube contracts during the infection of
- not all have tail fibers and base plates

Front 110

infection of host cells by phages

Back 110

1. adsorption
- tail fibers attach to specific receptors on bacterial cell and the host range of the phage
- host range of phage det by type of tail fibers
- receptors are proteins on outer surface of bacterium, LPS, pili, and lipoprtien (LPS for T4)

2.irreversible attachment
- attachment or the phage to the bacterium via one or more of the components oof the base plate

3. sheath contraction
- result of irreversible binding
- hollow tube pushed through the outer regions of bacterial envelop
- tail tube doesn't penetrate cytoplasmic membrane
- some phages have enzymes that digest various components of bacterial envelope instead

4. Nucleic Acid injection
- nucleic acid from head passes through tail and enters bacterial cell
- most of the phage stays outside and only DNA comes inside - different from animal cell viruses which most of the virus gets into cell - due to inabilit of bacterial to engulf materials

5. DNA uptake

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types of bacteriophage

Back 111

lytic or virulent = phage that multiply w/in host cell, lyse cell and release progeny phage (T4)

lysogenic or temperate phage
- either multiply via lytic cycle or enter a quiescent state in bacterial cell (lamda)
- expression of most phage genes repressed
- prophage - phage DNA in quiescent state
- lysogen - bacteria harboring a prophage
- DNA integrates into host chrom and replicated along w/host chrom and passed on to daughter cells

Front 112

events leading to lysogeny

Back 112

LAMBDA

1. circularization of the phage chromosome = cohesive ends via ligase
- sml ss regions at 5' ends complementary to each other (cohesive ends) bp

2. site specific recombination
- req - phage coded enzyme (integrase) and bacterial encoded IHF= integration host factor
- occurs btw a particular site on the circularized phage DNA and a particular site on host chromosome = integration of phage DNA into host

3. repression of the phage genome
- phage coded protein = repressor made and binds to a particular site on phage DNA = operator and shuts off transcription EXCEPT for the repressor gene
- stable represed phage genome integratedinto host chrom
- each temperate phage will only repress its own DNA very specific

Front 113

termination of lysogeny

Back 113

induction - adverse conditions
- DNA damage = UV, desiccation, ionizing radiation, mutagenic chem

- leads to production of proteases
- recA protein activated and destroys the repressor cl

gene expression
excision
lytic growth

Front 114

generalized trandsuction

Back 114

transduction in which potentially any donor bacterial gene can be transferred

1. infection of donor
2. phage replication and degradation of host DNA
3. assembly of phages particles (host and donor DNA via "head-full" mechanism)
4. release of phage
5. infection of recipient
6. homologous recombination


can transduce donor DNA piece into a recipient cell

Front 115

specialized transduction

Back 115

only certain donor genes can be transfered

1. excision of the prophage
2. replication and release of phage
3. infection of recipient
4. llysogenization of the recipient -homologous recomb possible

only host DNA on either side of the prophage may be transduced

Front 116

significance transduction

Back 116

common in gram positive bacteria
- lysogenic conversion
- corynebacterium diptheriae toxin - toxin derived from lysogenic phage

lysogenic conversion occurs in nature and is the source of virulent strains of bacteria

Front 117

cojugation

Back 117

gene transfer from a donor to a recipient by direct physical contact btw cells
direction of genetic material is one way

Front 118

mating types in bacteria

Back 118

1. donor - F factor (fertility factor) = extra piece of DNA circular that can replicate autonomously in cell = independent replicon (plasmids)
- has genes on it needed for its replication and ability to transfer DNA to recipient
- F (sex) pilus - coded for by F factor


2. recipient - lacks an F factor

Front 119

Physiological states of F factor

Back 119

- autonomous F+
= characteristics of F+xF- crosses
- F- becomes F+ while F+ remains F+
- low transfer of donor chromosomal genes
- carries only genes nec for its replication and DNA transfer

2. integrated Hfr - high frequency recombination
- characteristic of Hfr x F- crosses
- F- rarely becomes Hfr while Hfr remains Hfr
- high transfer of certain donor chromsomal genes
- F factor integrated into bacterial chrom via recomb event

3. autonomous w/ donor genes F'
- characteristic of crosses F' x F-
- F- becomes F' while F' remains F'
- high transfer of donor genes on F' and low transfere of other donor chromosomal genes
- F' made from excised section of Hfr from main chromosome containing almost all F but a little host + left behind some F on main chrom

Front 120

F+ x F- crosess

Back 120

pair formation - conjugation bridge - tip of sex pilus comes in contact w/recipient

DNA transfer -origin oftransfer
- plasmid DNA nicked at specific site = origin of transfer and replicated by rolling circle replication

single strand of DNA passes through the conjugation bridge and enters the recipient where second strand is replicated

recipient becomes F+ donor remains F+
low freq of transfer of donor chromosomal genes

Front 121

Hfr X F- crosses

Back 121

Pair Formation - conjugation bridge

DNA transfer
- origin of transfer
- rolling circle replication
- DNA that is transferred first is chromosome - depending upon where in the chrom the F factor has integrated and in what orientation different chrom genes will be transferred at different times
= only when the entire chrom is transferred will the F factor be transfered
homologous recombination

recipient doesn't recieve F factor

Front 122

F' x F - crosses

Back 122

Pair formation

DNA transfer - similiar to F+xF- crosses
F' has some chromosomal genes that will also be transfered

homologous recombnot nec but may occur

F- become F' and F' remain F'
high freq of transfer of donor genes on F' but low for rest of chrom genes
origin of transfer
rolling circle replication

Front 123

significance

Back 123

gran neg bacteria
- major way bact genes are transfered
- can be btw diff species
- transfer of multiple abx resistance
- recipient cell becomes donor after transfer of a plasmid

gram positive bacteria
- also have plasmids that can carry abx resistance
- transferred by conj
- others by transduction
- donor makes an adhesive material which causes aggregation w/ the recipient and DNA is transfered

Front 124

transposable genetic elements

Back 124

segments of DNA that are able to move from one location to another (jumping genes)

properties
- random movement
= from any DNA to any other DNA or to another location in same molecule
= not totally random preferred sites at which DNA molecule which transposable genetic element will insert

- not capable of self replication (not a replicon)

- transposition mediated by site specific recombination -
= little to no homology btw current location and new site
= mediated by transposase coded for by transposable genetic element
-recomb that doesn't require homology btw the recombining molecules is called site- specific or illegitmate or nonhomologous recomb

- transposition may be accompanied by duplication - one copy remains at original site and other is transposed to new site

Front 125

types of transposable genetic elements

Back 125

insertion sequences

transposons

Front 126

insertion sequences

Back 126

transposable genetic elements that ccarry no known genes except those that are required for transposition

nomenclature - IS1
IS followed by a nuber

structure
- sml stretches of DNA that have at their ends repeated sequences which are involved in transposition.

- In btw terminal repeated seq there are genes involved in transposition and seq that can control the expreession of the genes but no other nonessential genes present

Front 127

importance of insertion sequences

Back 127

1. mutation
- introduction of insertion seequence into a bacterial gene = inactivation of that gene

2. plasmid insertion into chrom - at or near insertion sequence in the chrom
phase variation - lagellar ag are one of the main ag to which the IR is directed in our attempt to fight off bacteria
- samonella 2 genes code for 2 Ag diff flagellar Ag
- expression of these genes reg by insertion seq
= samonella can change their flagella based on the IS attack

Front 128

transposons

Back 128

elements that carry other genes in addition to those involved in transposition

nomenclature - Tn10

sturcutre - sim to insertion seq
- extra genes located btw terminal repeated seq
- complete transposones the terminal repeated sequences are actually insertion sequences

importance
- many Abx resistance genes are located on transposons
- since transposons can jump from one DNA molecule to another - major factor in dev of plasmids that can confer multiple drug resistance on bacterium harboring a plasmid
-?

Front 129

plasmids

Back 129

extrachromosomal genetic elements capable of autonomous replication - replicon

Front 130

episome

Back 130

plasmid that can integrate into bacterial chromosome

Front 131

classification of plasmids

Back 131

transfer properties
- conjugative
= large w/all genes nec for replication - genes for sex pilus

- nonconjugative
= cannot mediate conjugation - smlr lack one or more of genes needed for transfer ofDNA
- can be transferred by conjugation if the cell also harbors a conjugative plasmid
phenotypic effects
- fertility

- bacteriocinogenic plasmid
= have genes that code for substances that kill other bacteria - bacteriocins or colicins

- resistance plasmid (R factors)
= unknown origin - likely evolved for other purposes

Front 132

structure of R plasmid

Back 132

genes for replication and transfer located on one part and resistance genes on another part

RTF - mediates transfer - carrier transfer genes

R determinate - carries abx resistance genes - often parts of transposons

Front 133

control of gene expression

Back 133

- transcriptional control
= transcription req the binding of sigma factor to the promoter of the gene or operon - which is a docking site for RNA polymerase
= no bacterial nuc so translation can start immediately - even before transcription is finished

- clustering of genes w/related fn

- coordinate control of genes w/related fn
=fnal related genes are located adjacent to each other and are regulated coordinately - one expressed all expressed

- polysistronic mRNA - regulating the production ofthis regulates coordinate regulation of clustered genes
- a large mRNRA containing information for many genes

bacteria able to sense their environment are express the appropriate genes needed for that environment by regulation transcription of those genes

Front 134

inducible genes

Back 134

oeron model

genes whose expression is turned on by the presence of some substance

- lactose induces expression of the lac genes
- an abx induces the expression of a resistance gene

- common in metabolic pathways that result in the catabolism of a substance and the inducer is norm the substrate for the pathway

Front 135

lactose operon

Back 135

atructural genes
lac z, lac y, and lac a
promoter
= polycistronic mRNA

regulatory gene = repressor
- operator
-operon
inducer = lactose
- absence - active repressor - no expression
- presence - inactivation of repressor, expression

NEgative control

Front 136

structural genes of lactose operon

Back 136

lac z = Beta galactosidase
- enzyme thta breaks down lactose to glucose and galactose

lac y - gene that codes for permease involved in uptake of lactose

lac a = galactose transacetylase

polycistronic mRNA = yield these 3 enzymes

reg by presence or absence of inducer

Front 137

regulatory gene of lac operon

Back 137

next to or far from genes that are being regulated

- the reg gene codes for specific protein called a repressor = acts by binding a specific region of the DNA called the operator which is adjacent to structural genes being regulated

Front 138

operon

Back 138

structural genes + operator region and promoter

binding of the repressor to operator prevented by the inducer which can also remove repressor already bound to the operator = transcription of structural gene

Negative control - fn of the regulatory gene product (repressor) to turn off transcription of the structural genes

Front 139

inducer

Back 139

induce transcription
- lactose or other beta galactosides

absence of lactose -> no lac mRNA
presence of lactose -> transcription

Front 140

caabolite repression

Back 140

control of an operon by glucose

usually seen in operons involved in the degradation of cmpds used as a source of energy

glucose is perfered source of E in bacteria - ensures bacteria will use glucose before any other type of c

Front 141

mechanism of catabolite repression

Back 141

inverse relationship btw glucose levels and cAMP levels in bacteria

when glucose levels are high - cAMP levels are high

relationship exists b/c transport of glucose into cell inhibts enzyme adenyl cyclase which produces cAMP

cAMP binds to a cAMP binging prot called CAP or CRP
the complex binds to site in promoters of catabolite repression sensitive operons = more efficient promoter = more initiations of transcriptions from that promoter

glucose transport inhibits adeylate cyclase -> lowers cAMP levels and fails to activate CAP = low glucose = increase cAMP

Positive control

glucose must be absent from enviroment and inducer must be present
if both present operon ill not be maximally expressed until glucose is metabolized

Front 142

repressible genes

Back 142

genes whose expression is turned off by the presence of somoe substance (co-repressor)

- tryptophan represses the trp genes

biosynthetic pathways
- co-repressor typically the end product of the pathway

Front 143

tryptophan operon

Back 143

structural genes
- trp E, trpD, trpC, trpB, and trpA
- enzymes involved in the syn of trp from common promoter into polycitronic mRNA
- common promoter

regulatory gene
- apo-repressor - inactive
- next to or far from the genes that are being regulated
- codes for repressor (apo-repressor) - when syn it is inactive - but activated by forminga complex w/co-repressor (trp)

operator
= active repressor/corepressor complex acts by binding to a specifc region of DNA adjacent to sstructural genes being regulated
- co-repressor and repressor is active and binds to the operator resulting in repression of transcription of the structural genes
- absence of co-repressor the repressor is inactive and doesn't bind to the operator = NEGATIVE CONTROL - turn off transcription of structural genes
leader
operon
co-repressor - tryptophan
- absence of trp - gene expression
- presence of trp = activates repressor, no gene expression

- negative control

Front 144

attenuation

Back 144

premature termination of transcription - in many repressible operons transcriptions that initiate at the promoter can terminate prematurely in a leader region that precedes the first structural gene

Front 145

leader region

Back 145

leader transcript
translation start and stop
trp codons

test peptide - contains several trp residues in middle of peptide = if enough trptophanyl t-RNA translate test peptide
- ribosome will be arrested at the 2 trp codons before it gets to the stop signala
- leader regional m-RNA contains 4 different region - w/complementary sequences

- several secondary stem and loop structures can be formed

- region 1 can only form base pairs w/ region 2
- region 2 can form base pairs w/ 1 or 3
- region 3 can form bp with region 2 or 4
- region 4 can only form bp with region 3
= 3 possible stem/loop structures can be formed in the RNA
---- region3 bp w/region 4 generates signal for RNA pol to terminate transcriptio = attenuate

Front 146

regulatoin of enzyme activity

Back 146

feed back inhibition

epigenetic modification
- post translational modifications
- phosphorylation/dephosphorylation
- adenylation/deadenylation

Front 147

pathogenicity

Back 147

- virulence factors
- number of initial organisms
- immunes status

Front 148

outbreak vs epidemic vs pandemic

Back 148

1. local
2. regional/natl
3. witespresd - international
- infections beyond the norm

Front 149

Koch's postulates

Back 149

1. isolated - dx not in healthy ppl

2. growth - pure culture

3. induce dx - susceptible animals

4. re-isolated - susceptible animals

Front 150

opportunistic infections

Back 150

- normal flora
- environment
-often compromised individuals

nomal flora found on skin -
- S. aureus
- staphyloccocus epidermidis
- propionibacterium acnes
-bacteroides
- enterobacteriaceae
- last 2 found in int, latter found in smaller numbers

in air water soil and food

community - acquired
nosocomial - hospital

Front 151

pathogenicity

Back 151

- virulence factors
- number of initial organisms
- immunes status

Front 152

outbreak vs epidemic vs pandemic

Back 152

1. local
2. regional/natl
3. witespresd - international
- infections beyond the norm

Front 153

Koch's postulates

Back 153

1. isolated - dx not in healthy ppl

2. growth - pure culture

3. induce dx - susceptible animals

4. re-isolated - susceptible animals

Front 154

opportunistic infections

Back 154

- normal flora
- environment
-often compromised individuals

nomal flora found on skin -
- S. aureus
- staphyloccocus epidermidis
- propionibacterium acnes
-bacteroides
- enterobacteriaceae
- last 2 found in int, latter found in smaller numbers

in air water soil and food

community - acquired
nosocomial - hospital

Front 155

Transmission

Back 155

1. airborn droplets
2. food
3. water
4. sexual contact

Front 156

Host defenses

Back 156

1. gut
- periistalsis
- defecation
2. resp tract
- ciliary action
- coughing
- sneezing
3. urogenital tract
- urination

Front 157

adhesion

Back 157

initiated by adherence of microbe to a specific epithelial surface of host

if doesnt then microb is removed through host defenses

involves interactions btw external constituents on bacterial cell (s\adhesions)and the host cell receptors *adhesion- receptor interaction)

Front 158

S. pyrogens and adhesion

Back 158

- surface constiuets include F-protein = fibronectin binding and lipoteichoic acid
- fibronectin binds to epithelial cells and F prot/lipoteichoic acid interacts w/fibronectin

Front 159

E. coli and adhesion

Back 159

several diff types

Type 1 fimbriae bind to mannose cont receptors

P fibriae allow binding to galactose cont glycolipids (cerebrosides and glycoprot on epithelial cells

Front 160

penetration and spread

Back 160

some bact resideon epithelial surfaces = Vibrio cholerae

Other species penetrate cells but remain locally

others pass into bloodstream or spread from there onto other systemic sites (intestine, urinary tract, and resp tract and less common through skin)

= Shigella penetrates epithelial cells of the intestine but don't spread into the blood stream
= samonella typhi pass through the epithelial cell and into blood stream

borrelia burgdorferi - transmitted into the bloodstream through skin by tick bite

certain degradative exotoxins secreted by some bacteria (hyaluronidase or collagenase can loosen up the CT matrix increasing the ease of passage of bacteria through these sites

Front 161

extracellular pathogens

Back 161

resistant to extracellular killing

killed by phagocytosis

resist killing by avoiding internalization by phagocytosis
- capsules, prot A (S. aureus), and M protein (S. pyogenes)

Front 162

intracellular parasite

Back 162

-avoid being killed w/phago-lysozomes
- occur by passing through or lysing these vesicles and residing free in cytoplasm

alternate - survive in phagosome - no fusio of lysosomes - or may be resistant to degradative enzymes if fusion occurs

Front 163

protein A of S. aureus

Back 163

secreted and binds to Fc portion of Ig blocking interaction w/human cell receptors
- bacteria on binding Ab activate classical complement cascade = phagocytosis

killing - cell mediated immunity

Front 164

M protein of S. pyogenes

Back 164

antiphagocytic surface component

binds fibrinogen from plasma - blocks complement bindingto the underlying PG layer

streptococci in non-immune serum are not phagocytosed

Front 165

tissue injury

Back 165

exotoxins

endotoxins and non specific immunity - no Ag

specific immunity - Ag

Front 166

exotoxins

Back 166

proteins - usually enzymes

destroy cellular structures and ECM

effects seen acutely 0 sufficiently potent that serious affects (death) often results
- anthrax, botulism, cholera and diptheria

if survives - neutralizing antibodies - anti-toxins elicited

Front 167

classes of exotoxins

Back 167

1. toxins which acto on ECM of CT
- Clostridium perfringens - collagenase
- Staphylococcus aureus - hyaluronidase

2. toxins which have a cell binding "B" component and an active "A" enzymatic component (A-B type)
- ADP-ribosylating activity

- lytic activity on 28S rRNA - shiga and shiga-like (vero) toxins
- afferent neurotransmission
- botulisum and tetanus

Front 168

scalded skin syndrome in newborn

Back 168

S. aureus - causes seperation of layers w/in the epidermis
toxins which act on ECM

Front 169

ADP-ribosylating activity

Back 169

- cholera toxin, E.coli heat labile toxin, = ADP ribosylating regulator - using NADH as a substrate
- B subunits form a ring w/A subunint in center - B binds to gangliosides on cell surface - channelt through which A penetrates
-adenylate cyclase activation, inc cAMP, active ion = decrease in sodium chloride uptake from lumen of the gut and water secretion = diarrhea
- Pseudomonas aeruginosa toxin, and diptheria toxin
- ADP-ribosylates elongation factor (EF2) Inhibits prot syn -kills cell destroys tissue
- diptheria toxin coded by phage tox gene - polypeptide chain and readily nicked into 2 chains held together by disulfide bond

Front 170

toxins that inhibit protein biosyn

Back 170

- shiga and shiga-like (vero) toxins
= shiga toxin = enterohemorrhagic E. coli = lyses 28 S rRNA ribosome = death of epithelial cells - poor water abs = diarrhea

A fragment of the A subunit passes to ribosome where it has N-glycosidase activity on 28SrRNA
- single adenosine residue is lysed

Front 171

Neurotransmission - exotoxins

Back 171

- botulinum toxin= inhibits Ach release = inhibit n impulses = mm inactive = flacid paralysis
- tetanus toxin = inhibits glycine release = inactive inhibitory neurons = mm over-active = rigid paralysis

Front 172

membrane damaging exotoxins

Back 172

- protesases
- phospholipids
- detergent like action

ex - alpha toxin= C. perfringens
- destroys BV stopping the influx of inflammatory cells
- helps create anaerobic environ imp for growth of this strict anaerobe
- delta toxin of S. aureus extremely hydrophbic protein - inserts into cell membranes believed to have a detergent like action

Front 173

endotoxin

Back 173

LPS - endotoxin = most potent

PG = endotoxin like action
- certain ones are poorly biodegradable = cause chronic/acute tissue injury

cell envelope components

NOT prot/enzymes

nonspecific inciters of inflamation = activates cells of IS to release cytokines IL1 and TNF ->attracts PMN
= also activate the alternate complement pathway (LPS and PG also alternate pathway)

B cell mitogens, polyclonal B cell activators and adjuvants-> dev of suitable chronic IR microbes not eliminated acutely
- toll receptors on human cells involved in these inflammatory processes

Front 174

Septic shock

Back 174

gram neg sepsis
25-40% of 200,000 who get it die

hypotension - due to tissue pooling of fluids
disseminated intra-vascular coagulation
- fever
fatal from - massive system failure = lack of effective oxygenation of sensitive tissues - brain

no effective therapy to reverse toxic activity of lipid A

Front 175

specific immunity and immunopathology

Back 175

cont generated ag released from persisting viable microbs will subsequently generate humoral and cell mediated imunity = immunopathology

chronic infection
- TB
- leprosy
- syphilis
- lymes dx

persisting bacterial remnants
= pneumococcal polysaccharide
= group A streptococcal cell walls
maintain immunopathology even in the absence of presistence of live agents

bact Ag cross-react w/host tis Ag = autoimmunity (M prot of S. pyogenes cross reacts w/mammalian myosin

Front 176

Immune system in resistance to infection examples

Back 176

1. IgA proteases= help survival on external surfaces
H. influenzae
S. pneumoniae
N. gonorrhoeae
N. meningitidis

2. Intra-cellular parasites are primarily killed by cell mediated immunity

3. extra-cellular parasites Abs cause lysis of the organism and/or their opsonization by phagocytes at which pt they are rapidly killed

4. exotoxins can be neutralized by antitoxins = toxoid vaccines
= toxoids are antigenic but unlike toxins aren't toxic - toxoids used for vaccination againts diptheria

Front 177

bioterrorism

Back 177

air - most common

no previous exposure - zoonoses

manifest initially
- colds/flue-like - days after exposure
=> death/debilitation

recognition
- clinically (common source clusters)
- clinical microbiology
- biodetection (enviro) -future

major ones
1. bacillus anthracis
2. yersinia pestis
3. francisella tularensis
4. brucella melitensis

Front 178

gram negative aerobic cocci

Back 178

neisseria

Front 179

gram positive cocci (faculative anaerobes)

Back 179

streptococcus
staphylococcus

Front 180

spirochetes

Back 180

treponema
borrelia
leptospira

Front 181

gram positive anaerobic cocci

Back 181

peptococcus
peptostreptococcus

Front 182

spiral, gram neg

Back 182

campylobacter
helicobacter

Front 183

endospore forming gram positive rods

Back 183

bacillus (aerobic)

clostridium (anaerobic)

Front 184

gram negative aerobic rods

Back 184

pseudomonas
burkholderia
bordetella
francisella

Front 185

gram positive asporogenous aerobic rods

Back 185

listeria
erysipelothrix

Front 186

gram negative faculative rods

Back 186

enterobacteriaceae
escherichia
salmonella
shigella
yersinia
enterobaccter
proteus
serratia
edwardsiella

Front 187

actinomycetes and related org

Back 187

corynebacterium
mycobacterium
nocardia
actinomyces

Front 188

corynebacterium-like in appearance

Back 188

propionbacterium

Front 189

curved gram neg faculitative rods

Back 189

vibrio

Front 190

simple gram neg bacteria

Back 190

chlamydia
mycoplasma, ureaplasma
rickettsia, coxiella
erlichia

Front 191

other gram neg bacteria

Back 191

bartonella
brucella
hemophilus
legionella

Front 192

gram neg anaerobic rods

Back 192

bacteroides

Front 193

bacillus anthracis
toxins

Back 193

dx = anthrax
toxin
1. edema toxin
- edema factor/ protective complex - adenylate cyclase
2. lethal toxin
- lethal factor/protective antigen complex
- metalloprotease

Front 194

bordetella pertussis
toxins

Back 194

dx = whooping cough

toxin
1. pertussis toxin = ADP ribosyltransferase
2. adenylate cyclase toxin = ATP converted to cAMP
3. tracheal cytotoxin = peptidoglycan fragment

Front 195

clostridium botulinum
toxins

Back 195

dx = botulism

toxin = botulinium toxin = blocks release of Ach at neuromuscular junction

Front 196

clostridium difficile toxins

Back 196

dx- pseudo-membranous colitis

toxin = enterotoxin = cytotoxin

Front 197

clostridium perfringes toxins

Back 197

dx = gas gangrene

toxin = alpha toxin = phospholopase (lecithinase

dx = food poisoning
toxin = enterotoxin = hyaluronidase

Front 198

clostridium tetani toxins

Back 198

dx = tetanus

toxin = tetanospasmin
- blocks inhibitory neurones

Front 199

corynebacterium diphtheriae toxins

Back 199

dx= diptheria

toxin = diptheria toxin
inhibits elongation factor 2 (EF2) by ADP -ribosylation

Front 200

E. coli toxins

Back 200

dx - diarrhea ETEC

toxin
1. Heat labile toxin - actives adenyl cyclase
2. heat stable toxin - activates guanyl cyclase

dx = hemorrhagic colitis
toxin - shiga toxin (vero toxin)

Front 201

listeria monocytogenes toxins

Back 201

dx = listeriosis

toxin - listeriolysin
- pore forming ch-dependent cytolysin

Front 202

pseudomonas aeruginosa toxins

Back 202

dx of compromised host

toxin - exotoxin A - inhibits EF2

Front 203

staphylococcus aureus toxins

Back 203

dx - opportunistic infections
toxin- alpha-delta toxins, leucocidin = cytotoxins

dx = toxic shock
toxin - toxic shock toxin = super Ag

dx= food poisoning
toxin = enterotoxin

dx= scalded skin syndrome
toxin = exfoliatin = exfolation

Front 204

streptococcus pyogenes toxin

Back 204

dx= scarlet fever
toxin = erythrogenic =super ag

dx- toxic shock
toxin = pyrogenic toxin

Front 205

shigella dysenteriae toxin

Back 205

dx = bacillary dysentery
toxin = shiga toxin
= inhibits prot syn by lysing 28S rRNA

Front 206

Vibrio cholerae toxin

Back 206

dx = cholera

toxin = choleragen = activates membrane adenyl cyclase by ribosylation ADP

Front 207

enterobacteriaceae

Back 207

include several species that cause primary infections of the human GI tract
aka enterics

gram neg facultative anaerobic rodes = oxidase negative - no cytochrome oxidase

certain strains of E.coli and Salmonella
all 4 species of shigella
Yersinia entercolitica

Front 208

Reiter's syndrome

Back 208

rheumatic dx
assoc w/HLA-B27

result from prior exposure to salmonella, shigella, or Y.enterocolitica

- Campylobacter and chlamydia also causitive agents but not enterobacteriacea members

Front 209

opportunistic infection - enterobacteriasecea

Back 209

septicemia
pneumonia
meningitis
UTI
- members of enterobacteraciea cause these
- citrobacter
- enterobacter
- escherichia
- hafnia
- morganella
- providencia
- serratia

Selection of Abx therapy is complex due to diversity of organisms

Front 210

Community acquired enterobacteriacea

Back 210

otherwise healthy ppl

1. klebsiella pneumoniae
- resp dx
- prominent capsule aiding pathogenicity

2. UTI
- fecal contamination
- E. coli -most common
- Proteus
- urease - degrades urea
- alkaline urine

Front 211

E. coli pili

Back 211

2 major classes
mannose sensitive and mannose resistant pili
mannose sensitive pili - bind to mannose cont glycoproteins = type 1

resistant to cerebrosides ( galactose - glycolipids/glycoproteins) on the host epithelium allowing attachment = P

Front 212

isolation of enterobacteriaceae

Back 212

isolated from fecal matter on agar containing:
- lactose
- pH indicator
= Mackonkey's agar

Colonies that ferment lactose = produce sufficient acid to cause a color shift in the indicator
usually isolated from feces

other sites (lungs,brain etc) - Ided biochemically

Front 213

E. coli identification

Back 213

- lactose positive - ferments it
- often not Ided from feces
- lactose positive species common - healthy intestine

Front 214

shigella, salmonella, yersinia

Back 214

lactose negative

salmonella unlike shigella produce hydrogen sulphide generating a black ppt

Front 215

Serotypes to ID

Back 215

not performend in routine clinical lab but reserved for defining outbreaks

- O Ag - LPS
- H Ag - flagellar
- K Ag - capsular

Front 216

diarrhea vs dysentery

Back 216

diarrhea - watery feces
dysentery - blood in stools

Front 217

E.coli and shigella

Back 217

genetically very similiar
separated for historical reasons
overlap in pathogenesis

Front 218

Enterohemorrhagic E. coli

Back 218

O157: H7 - other serotypes too

Transmission - meet products or sewage - contaminated veggies

Hemorrhagic colitis
- bloddy dysentery
- copious diarrhea
- few leukocytes
- afebrile
- often hamburger meat or veggies cont w/feces
- shiga toxin (aka vero toxin) disseminates into bs produces hemolytic uremic syndrome - most potent toxin
- also toxin - hemolysin

Hemolytic-uremic syndrome
- toxin disseminates in blood stream
- dx often self-limiting
- abx not recommended
- hemolytic anemia
- thrombocytopenia (low platelets)
- kidney failure

selective medium for EHEC developed

Front 219

Enterotoxigenic E. coli

Back 219

- diarrhea like cholera but milder
- travellers diarrhea
- ETEC
- 2 types of plasmid-encoded toxins are produced
- heat labile toxins similar to choleragen -> adenyl cyclase is activated - production of cAMP and increased secretion of water and ions

2. heat stable toxins - guanylate cyclase activated - inhibits ionic and water uptake from gut lumen -> watery diarrhea, fever and nausea

Front 220

Enteropathogenic E. coli

Back 220

destruction of surface of microvilli w/o invasion = adhesion imp (EPEC)

- fever
- diarrhea
- vomiting
- nausea
- non-bloody stools - not generally seen as dysentery)

commonly assoc w/infant diarrhea

Front 221

enteroaggregative E.coli

Back 221

- brick like bacterial aggregates - cell surfacese
-mucus biofilm inhibits fluid abs - don't invade
- diarrhea

RARE in US and developing world

Front 222

enteroinvasive E. coli

Back 222

produces dysentery

indistinguishable from shigellosis

Front 223

tx of gastrointestinal dx

Back 223

fluid replacement in severe cases

abx in shigella
NOT in salmonellosis or E. coli

Front 224

Shigella

Back 224

S. flexneri
S. boydii
S. sonnei
S. dysenteriae

- bacillary dysentery
- shigellosis
1. bloody feces
2. intestinal pain
3. pus
- w/in 2-3 days - epithelial damage - invades epithelial lining layer bud does not penetrate = release mucus and blood and attraction of leukocytes from damaged epithelium

Shiga toxin - chrom encoded = neurotoxic, enterotoxi, cytotoxic
- toxin inhibits prot syn acting on 80S ribosome and lysing 28S rRNA

primarily dx of young kids = fecal to oral contact - adults can catch from kids
can be transmitted by infected adult food handlers = contaminating food = unwashed hands
man is the only reservoir

tx- usually tx w/antibiotics (ampicillin) = shortens dx duration
- manage dehydration

Front 225

Salmonella

Back 225

- 2000 antigenic types
- genetically single species = S. enterica
- dx category
1. S. enteritidis - many serotypes
2. S. cholerae-suis
3. S. typhi

Front 226

S. enteritidis

Back 226

Salmonellosis

common salmonella infection
poultry/eggs
no human reservoir

gastroenteritis
1. n/v
2. non-bloody stool
3. self limiting - 2-5 days

control - by monitoring of food in US is limited - microbiology is difficult
- regulation not optimal
- chickens are not vaccinated in US
in UK salmonellosis is largely erradicated

in uncomplicated cases - majority - abx therapy not useful

Front 227

S. cholerae-suis

Back 227

much less common

causes septicemia after invasion

abx required

Front 228

typhoid

Back 228

- most severe salmonella dx
- salmonella typhi
- enteric fever
- rare in US
- epidemics in third world and historically in europe

human reservoir - carrier state common
- contaminated food, water supply, poor sanitary conditions

1. invades the intestinal epithelium and during this acute phase, gastrointestinal sx are noted
2. org penetrates usually w/in first week to bloodstream = disseminated in macrophages = typical features of systemic bacterial infection
3. septicemia = temp (occurs after 10-14 days and lasts 7 days) w/organism finally lodging in the gall bladder
4. org shed into intestines fro weeks = gastroienterits again

Vi capsular Ag

Abx therapy essential - vaccines not widely effective and not generally used

Front 229

Yersiniosis

Back 229

Yersinia entercolitica
- gastroenteritis
- common in scandinavia
- US colder regions

transmission
- fecal contamination, domestic animals
- water/milk
-meat

characterized by
- diarrhea
- fever
- abd pain
- bacteremia

Survives in refridgerator while other org don't = isolation

similiar - les severe dx caused by Y. pseudotuberculosis

Abx reccommended

Front 230

differentiating enterics

Back 230

McConkeys Agar
lactose positive = pink colonies = E.coli
lactose negative = colorless colonies = salmonella shigella

Salmonella-Shigella agar
- black ppt from HS production = salmonella

Front 231

Vibrios

Back 231

gram neg rods
comma shaped
facultative anaerobes
oxidase positive
simple nut requirements
readily cultivated

Front 232

V. cholera

Back 232

causes cholera
third world
US - uncommon - traveler, ingestion of sea food

- found in feces of an infected individual and ends up in the water supply if sewage untreated => transmitted by drinking cont water - survives in fresh and salt water
- food after water contamination

once in the gut the org adheres to epithelium w/o penetration - adhesion to microvilli

cholera toxin - choleragen secreted = contains 2 types of subunit A and B
- B binds to gangliosides = allowing internalization of the A subunit
- provides channel for A
- A catalyse ADP- ribosylation
- regulator complex - activates adenylate cyclase
- overproduction of cAMP = stimulates massive secretion of ions and water into lumen

dehydration and death w/o tx = Abx therapy (including tetracycline)
- vaccination only partially effective - ot generally recommended - used in international travelors

Front 233

Vibrio parahemolyticus

Back 233

- raw sea-food
- grows best in high salt
- not common in US
- diarrhea - non bloody
- not as severe as cholera

Aeromonas and Plesiomonas areother water-borne org causing GI dx

Front 234

Vibrio vulnificus

Back 234

-wound infections

most common vibrio infection in US

Front 235

campylocbacter and helicobacter

Back 235

gram neg rods

curved or spiral

genetically related

Front 236

campylobacter jejuni

Back 236

pleomorphic

transmissions-
- infects the intestinal tract of animals - chickens, cattle, sheep

transmitted in milk and meat products

isolation - grows best at 42 deg C and is microaerophilic

sx
1. diarrhea
2. dysentery common
3. malaise
4. fever
5. abd pain
6. usually self limiting
7.abx occasionaly
8 bacteremia- sml minority

invades gut lumen bu t generally lesss so than shigella

assoc w/ Guillan Barre syndrome (rare neurologic cond

Front 237

helicobacter pylori

Back 237

stomach mucosa
ulcers

chhronically lives in and on stomach mucosa of man

ulceration leads to increase risk of cancer

culture = urease -> NH4 + CO2

- direct detection of urease which generates ammonia annd carbon dioxide
- imp in neutralizing stomach acid (ammonia)
- large amts produced = directly detected in mucosa sampled afterendoscopy

- CO2 derived from labeled urea 13C or 14C labeled CO2 detected in breath after feeding labeled urea

Abx eliminates org peptic ulcers heal and relapses are generally avoided

Front 238

Spirochetes

Back 238

gram neg
- long, thin, helical, motile
- axial filaments - locomotion - between peptidoglycan layer/outer membrane - runs parallel

1. treponema
2. borrelia
3. leptospira

Front 239

Treponema pallidum

Back 239

syphillis

transmission - genital/genital or inutero or during birth

chronic and slowly progressive
3rd most common STD

primary lesion - chancre
- 10-60 dyas
- area of ulceration/inflammation
- many orgnaisms

secondary - 2-10 weeks later
- systemic spread
- flu like sx
- skin, particuraly
- many orgnaisms = higly infectious

tertiary
- several years later - rare - only if not tx
- skin
- CNS
- delayed hypersensitiveity
- few organisms - control by immune response - extremely difficult to detect spirochetes

Not culturable - missing krebs cycle and other metabolic pathways
- microbiol diagnosis of primary syphillis by:
1. dark field microscopy
- actively motile organisms
- brightly lit against dark back drop
- light shines at an angle
- refleced from thin organisms
- enters objective

2. conventional light microscopy
- light shins through
- not visualized
3. fluorescence microscopy - antibody staining

Secondary and tertiary syphilis diagnosis by:
Serological methods - serum Ab to cardiolipin - result from tissue inj and autoimmunity to self components - other dx result in anti-cardiolipin Ab - false positives are common
- specific diagnosis
- ab to against treponemal ag - more expensive - used only after positive cardiolipin Ab

No vaccine but Abx therapy used - penicillin G

third world = bejel, yaws, and pinta

Front 240

borrelia burgdorferi

Back 240

lyme dx

tick vector= Ixodes scapularis aka ixodes dammini - transmitted by tick bite (mice and deer)

sx -
- erythematous skin rash a few days after bite
- transient bacteremia -> severe neurological symptoms or poly artheritis= months to weeks later
- cardiac problems in minority

- abx initiated early = cure but if late = ineffective (penicillin or tetracylcine)

diagnosis -
- serum Ab to B.burgdorferi
- labatory strains - grow extremely slow, tissue culture media, not bbacteriological media
- pts body fluids/tis sample almost never grown
- but acutely Ab may not be detected and most ppl dont know that they've been bitten or had a rash

etiology of artheritis - a reactive arthritis similar to Reiter's syndrome and rheumatic fever

resembles rheumatodid arthritis

Front 241

Relapsing fever

Back 241

less than 100 cases in US
assoc w/bacteremia
caused by
Borrelia hermsii (rodent host - tick)
B. recurrentis (human host - lice)

IR = dx relapses
Ag expressed change and dx reappears
difficult to culture - no serological test
detected by blood smear(microscopically)

Front 242

Leptospirosis

Back 242

less than 100 cases a year in Us

Sx = flu like or sever systemic dx
also - zoonotic infection

transmitted in water contaminated w/infected urine from wild animals (including rodents)
- taken in in farm animals through broken skin when swimming

Infects kidney, brain and eye

most readily culturable of pathogenic spirochetes
= diagnosis by serology

Front 243

Neisseria gonorrhoeae

Back 243

Found only in man

causative agent of gonorrhea - 2nd most common veneral dx
- causes an effusion of PMN
- smear = gram negative cocci present in cells

dissemination - gonococci
- gonococcal arthritis - septic arthrits
- dermatitis

abx therapy - beta lactamse resistant cephalosporin = ceftriaxone

resistant strains- common, produce beta lactamases which destroy penicillin

no vaccine - strains are highly variable in external Ag - outer membrane and pili as well as surface Ag

pili/outermembrane prot involved in adhesion of organism to genital epitheliup

outermembrane proteins include Opa (opacity proteins) - colonies are opaque

produces IgA protease (also produced by N. meningitidis) - involved in successful colonization
- LPS and PG =tis inj

PCR-based assay commonly used for clinical diagnosis w/o culture - dual test w/chlamydia

Front 244

Neisseria

Back 244

- gram neg
- diplococci - pairs of cocci
- oxidase positive = produce cytochrome oxidase) = flood plate w/ dye that on oxidation changes color

Culture in choclate agar - contains heated blood - brown color - modified one most commonly used = Thayer Martin - selective = presence of Abx that stop rowth of many bacteria

Front 245

N. meningitidis

Back 245

resides only in men

usually sporadic cases - mostly young kids

outbreaks in adults or crowded conditions - army barracks, dorms

upper resp tract infection by binding of pili -> invades bloodstream -> brain

2nd most common cause of meningitis (pneumococcus most common)

fatal if untx but responds well to abx

detectable in CSF - gram neg diplococci w/ PMN or antiigenically
- culture on Thayer Martin essential for definitive diagnosis

abx = penicillin

vary antigenically - sero-grouped w/anti-capsular Ab - capsule imp pathogenesis factor = inhibition of phagocytosis

vaccine that targets most common capsular Ag widely used

Front 246

streptococci

Back 246

faculative anaerobe
gram positive
usually chains - sometimes oairs
catalase negative

IDed by lancefield groups - carbohydrate Ag - groups include one or more species
- A, B, D are frequent (A most common infectious dx - pharyngitis)
- C, G, F are less frequent
- streptococcus pneumoniae and streptococcus mutans (viridians streptococci -detal carries) do not posses Ag

hemolysis rxn - sheep blood agar
- alpha - partial hemolysis - green color
- beta - complete clearing
- gama - no lysis - white colonies

Group A and group B streptococci are beta hemolytic
Group D are usually alpha or gamma
streptococcus pneumonaie and viridians are alpha hemolytic

IDed by hemolysis rxn + one biochem characteristic

Front 247

Group A streptococcus

Back 247

S. pyogenes

affects all ages - peak incidence at 5-15 years of age

non-invasive - pharyngitis - suppurative = rheumatic fever
- skin infection, impetigo

invasive bacteremia = S. saureus - lower frequency
- toxic shock-like syndrome
- "flesh eating bacteria
- pyrogenic toxin = superag, non specific activation of T cells = cross-link Ag presenting cells MHC and T cell receptor = cytokine production

serious complications (rheumatic fever and bacteremia primarily affect those w/underlying defect in IS = infants, elderly, immunocomporomised

Front 248

Rheumatic fever

Back 248

non-suppurative dx of the heart occur after initial pharyngitis subsides of group A streptococcus
S. pyogenes

inflammatory dx
life threatening
chronic sequalae
- fever
- heart
- joints

M protein cross reacts heart myosin = autoimmunity

group A streptoccoci cell wall Ag poorly digested in vivo - persist indefinatly

early termination of throat infections w/penicillin = decreases the incidence of subsequent rheumatic carditis

Front 249

scarlet fever

Back 249

characteristic rash rash
erythrogenic = phage encoded

group A streptococci

Front 250

Acute glomerulonephritis

Back 250

immune complex dx of kidney

usually observed after pharngitis
group A streptococci

Front 251

bacteremia and toxic shock due to streptococcal infection

Back 251

invasive forms of streptococci

include:
1. rash
2. fever
3. edema
4. necrotizing myositis and fascitis

strains that often produce pyogenic toxins A, B, C - superag

dx uncommon but progress quickly - few days =- life threatening

pyrogenic toxin and erythogenic toxin = same protein

Front 252

major pathogenesis factors of group A streptococci

Back 252

Adhesion = lipoteichoic acid in cell membrane
and Fibriae on cell exterier (F-protien)
- binds to epithelial cells via fibronectin

M protein - anti-phagocytic
- found in fimbriae
- binds fibrinogen from plasma and blocks binding of complement to underlying peptidoglycan
- vaccine fear that would cross react and cause rheumatic carditis
- distinct protective cross reactive epitopes found = vaccine made
- vary antigenically btw strains - immunity to one M protien = doesn't equal immunity to all s. pyogenes

M typing along w/other Ag (t and R) were primarily used for serotypiong but now replaced by sequencing the gene coding for M protien

- strains can be mucoid or non mucoid
- mucoid - prominent capsuls - inhibit phagocytosis - assoc w/invasive bacteremias
- neutralizing Ab reactive w/M protien elicit phagocytosis -= killing

Front 253

isolation and identification of group A streptococci

Back 253

1. direct detection w/o culture - Ag extracted from throat swab
- Ag bind w/Ab specific to group A streptococcal carbohydrate = agglutination of Ab coated beads = results w/in minutes

2. testing colonies
a. lancefield grouping of isolated beta hemolytic colonies
b. colonies are beta hemolytic and procuce an enzyme (pyrriolidonyl amidase) that in the presence of appropriate substrate produces a red product
c. colonies are beta hemolytic and growth inhibited by bacitracin

3. test pt serum for Ab to streptolysin O or other streptococcal Ag
- imp if delayed clinical sequelae occur

Front 254

beta hemolysis

Back 254

caused by 2 hemolyins (streptolysins)
1. O - inactive in presence of oxygen = stabbing of the plate increases intensity of hemolysis = cytotoxin - chloesterol binding induced pore formation
2. S - insensitive to oxygen

Front 255

Group B streptococcus

Back 255

S. agalactiae

- neonatal meningitis
- septicemia
transmission from normal vaginal flora of mom to infant

Identification - beta hemolysis
- hydrolysis of hippurate
- CAMP rxn - i

produce a factor that increases beta hemolysis of S. aureus indicator strain

Front 256

group D streptococcus

Back 256

growth on bile esculin agar
- black ppt - derived from esculin
- many other bacteria will not grow in the presence of bile

- divided into groups whether it will grow on 6.5% saline (enterococci) and those that will not (non-enterococci)

Front 257

enterococci

Back 257

group D streptococcus that grows on 6.5% saline

distalntly related to other streptococci
- genus Enterococcus
- gut flora
- urinary tract infection - fecal contamination = LESS COMMON THAN E. COLI
- opportunistic infections - endocarditis (intra abdomina, septicemia)

-most common E. (S.) faecalis

often resistant to many common abx - including vancomycin - terminal D-ala replaced by D-lactate

alpha or gamma hemolytic

Front 258

Group C and G streptococci

Back 258

occasonially cause human dx

particullarly pharyngitis

- rarely group F

Front 259

Minute colonly streptococci

Back 259

various groups (may be A or C or other groups) or non groupable. hemolysis
- genetically distinct from large colony (S. pyogenes)

- group A minute colony doesen't cause rheumatic fever

Front 260

Viridans streptococci

Back 260

- diverse species including S. mutans
- commonly found orally
- cause endocarditis after release into bloodstream from tooth extraction
- involved in dental carries
- alpha hemolytic
- negative for any other test
- non groupable

Front 261

Streptococcus pneumoniae

Back 261

Leading cause of pneumonia
- particularly young and old
- member normal flora, nasopharynx
- replication and spread after damage to upper resp tract (after the flu)
- also causes middle ear infections in the young
- bacteremia
-meningitis

- pairs of cells - diplococci
- alpha hemolytic - no group Ag

- vaccination - highly effective
- direct gram staining - detection of capsular Ag i nCSF - diagtnostic - limited sensitivvity
- grows well on sheep blood agar

pneumolysin - degrades RBC under aerobic conditions

autolysin - identified by solubility in bile
- autolysin (PG degrading enzyme) released by bile from cell membranes (from lipoteichoic acid) and binds to a choline- cont teichoic acid attached to PG
- autolysin then digest the bacterial cell wall by resulting in lysis of the cell
- techioic acid - C polysaccharide - ppt a serum globulin fraction present in inflammatory states (C-reactive protein)

also IDed by susceptibility to optochin

pathogenesis
- teichoic acid - complement activation
- large number of inflammatory cells at infection site

tx = ,pst strains susceptible to penicillin - resistance common - Vancomycin alternative

Front 262

S. pneumoniae capsule

Back 262

prominent - virulent strains

carb Ag vary greatly in structure among strains

anti-phagocytic
immunization is primarily against capsule

capsular vaccine is highly recommended for susceptible individuals- elderly and young

immunity is serotype specific - vaccine directed against a mixture of capsular Ag of most virulent strains (polyvalent)

Front 263

quellung rxn

Back 263

appropriate type-specific anti-sera the capsule on isolated bacteria can be fixed and becomes visible microscopically
useful in microbial identification

S. pneumoniae

Front 264

staphylococci

Back 264

gram positive
faculative anaerobes
grape like-clusters
catalase positive
major components of normal flora of skin and nares

Front 265

staphylococcus aureus

Back 265

most common cause of opportunistic infection both in hospoital and community acquired:
1. pneumonia
2. osteomyelitis
3. bacteremia
4. endocarditis
5. abcesses/boils
6. other skin infections

abx therapy
- resistant to penicillin - penicillinase - degrades beta lactam abx
- resistant to methicillin - modified penicillin binding protein
- methicillin resistant S. aureus (MRSA)

Vancomycin - current drug of choice - resistance observed but rare

hospital infection control - MRS serious problem - monitoring by PCR of nasal swabs
- eradication by antibiotics - whole body anisepsis

Food poisoning
- not an infection
- food contaminated by humans - growth of bacteria - production of enterotoxin
- onset and recovery occur w/in few hours
- V/n diarrhea and abd pain

Toxic shock syndrome
- after super tampon use - now off market
- fever
- rash
- desquimation
- vomiting
- diarrhea
- toxic shock toxin involved - organism doesn't disseminate but toxin does

ENterotoxin and toxic shock toxin both super ag

Scalded skin syndrome in babies - exfoliative toxin

lytic exotoxins
- alpha toxin
- beta toxin (sphingomyelinase C)
- gamma toxin
- delta toxins - detergent like
- leucocidins
hyaluronidase = tissue degrading enzyme -aids in spreading of orgainsim

free protein A binds to Ig and complement blcoking Fc and complement receptors inhibits phagocytosis

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identification of S. aureus

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beta hemolytic on sheep blood agar
mannitol fermentation
golden pigment often
coagulase positive
phage typing rarely used

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Staphylococcus epidermis

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less common cause of oppurtunistic infections that S. aureus
- mediator of nosocomial infections - catheters, shunts, artificail heart valves/ joints

major member of skin flora

identification
- non-hemolytic on growth of sheep blood agar
- doesn't ferment manitol
- non pigmented
- coagulase negative

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staphylococcus saprophyticus

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UTI
- coagulase negative speicies
-not usually differentiated from S/ epidermidis

human skin several staphylococcal species - also cause dx - also coagulase negative

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to determine Streptococcus/ Staphylococcus and what kind ....

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once discovered gram neg
1. Catalase test
positive = staphylococcus - clusters
negative = streptococcus - pairs and chains

staphylococus
then do coagulase tests
+ = S. aureus - beta hemolytic - mannitol yellow
- = S. epidermidis - non hemolytic- mannhitol white

Streptococcus
hemolytic test
Beta: bacitracin + = > S. pyogenes (group A)
CAMP/Hippurate + => S. agalactiae (group B)
Alpha: optochin/bile solubility + => S. pneumoniae
Gamma or alpha: bile esculin + / 6.5% NaCl -> group D enterococcus
Gamma or aloha: bile esulin positive/ 6.5% NaCl negative => group D non-enterococcus

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obligate anaerobes

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bacteria that can't survive in the presence of high oixidation pot/high oxygen content
- no ox phos
- use fermentation
- killed by oxygen
- lack - superoxide dismutase, catalase, peroxidase

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polymicrobic anaerobic infection

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many species in human flora
grow simultaneously - opportunistic conditions

strict anaerobes - grow when there is tissue inj - limitation of blood supply = opportunistic growth of obligate anaerobs

often more than one species infects the same site
= simultaneous infection w/facultative anaerobe - encourages growth of obligate anaerobes

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Endogenous vers exogenous infection

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sources
normal human flora = endogenous = non- spore formers - anaerobs
environment - soil = exogenous - anaerobic spore formers - clostridia

nonspore formers rarely produce exotoxins in contrast to spore formers

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sites of anaerobes in normal flora

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intestine - major site
95-99% total bacterial mass
- most common forms of infections after abd surgery or other gut injury
1. enterobacteriaceae facultative anerobes- commonly cause dx - low numbers in gut flora and then
2. B. fragilis - strict anaerobes - much less commonly cause dx - high nubmers in gut flora
both minor components of gut flora

mouth

genitourinary

infectuous dx - sites throughout body
- mm, cutaneous/sub-cutaneous necrosis, abceses

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problems in identification of anaerobic infections

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1. often from normal flora - sample contamination can confuse
2. if air gets into the sample during sampling or transportaiton to lab - org may not be isolatable
3. slow growth of org - inefficiency of fermentation - isolation takes several days or longer

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laboratory identification of anaerobes

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1. biochemical kits - sustrate utilization
2. gas chromatography - volatile fermentation products - short chain FA/ alcohols

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anaerobic non-spore-formers of clinical importance

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gram neg rods
1. Bacteroides -= B. fragilis
2. fusobacterium
3. porphyromas, prevotella

gram positive rods
1. actinomyces
2. bifidobacterium
3. eubacterium
4. lactobacillus
5. mobiluncus
6. Propionibacterium

Gram positive cocci -
1. peptostreptococcus
2. peptococcus

gram neg cocci
1. veillonella

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Bacteroides fragilis

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major dx causing strict anaerobic non spore former

prominent capsule - anti-phagocytic
- abcess formation

endotoxin
- low toxicity
- structure different than other LPS
- beta lactamase

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anaerobic spore-formers

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Clostridia

- gram positive, rods
- human intestine
-soil

1. C, botulinum
2. C. difficil
3. C. perfringens
4. C. tetani

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Clostridium tetani

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commonly found in soil - contamination of wounds = tetanus

exotoxin - tetanospasmin - binds to ganglioside receptors on inhibitory neurons in CNS
-> stops nerve impulse transmission to mm = rigid/ spastic paralysis - continued severe mm contraction and spasms -= fatal (resp failure)
- an A-B toxin A chain is a peptidase
- glycine neurotransmitter
-can break bones

non invasive - remains local in wound

vaccination of infants w/tetanus toxoid (DPT diptheria, pertussis and tetanus)

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C. perfringens

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causes wound colonization after soil - gas gangrene - fecal contamination too
- swelling of tissues
- gas release - fermentation products
- tissue destruction

primarily seen in times of war

alpha toxin (lecithinase, phospholipase)
- primary entity involved in tissue destruction - tissue degrading enzymes
- Perfringolysin ) - cholesterol binding cytotoxin - synergistic effect
- myonecrosis
- destruction of BV
- anaerobic environment created
- death can occur w/in 2 days w/o tx - systemic spread

tx - effective abx therapy, anti-toxin, debridement = amputation/death rare

IDed in lab by production of lecithinase
- significant cause of food poisoning by enterotoxin producing strains

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C, botulinum

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rare but fatal form of food posioning = Botulism

- potent exotoxin - botulinum toxin - binds to receptors on peripherial n (ach nt) and inhibits nerve impulses = flaccid paralysis = death resp/cardiac failure
- A-B toxin A chain = peptidase

doesn't grow in gut but preformed exotoxin from prior germination of spores present in inadequately autoclaved canned food = NOT an infection

wound botulism can occur but rare

infection w/C. botulinum = neonatalo botyulism - uncommon = predominant form of botulism
- colnization occurs - limited normal flora to compete

tx - anti-toxin and abx therapy for neonates

botulinum toxin used as a biological warfare agent - not live agent = chemical attack

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C. difficile

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norm flora of int altered by abx therapy - multiply and pseudo membranous colitis

produces exotoxin A - enterotoxin w/cytotoxic activity

exotoxin B - cytoxin - secondary role

therapy - discontinuation of implicated antibiotic (ampicillin)
severe cases - vancomycin

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pseudomonas aerginosa

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gram negative rod
aerobic
polar flagella
oxidase positive
majority of human infections

common in enviro - water, air, soil - water loving commonly transmited in air

host infected
- burns and wounds - destruction of bv limits access of phagocytosis
- after use of cytotoxic drugs in cnacer therapy
- alteration of resp epithelium in CF -> pneumonnia

identification
- pigments = pyocyanin (blue-0green)
- pyoverdin (green-yellow, fluorescent
- biochem rxns - cultures have fruity smell

pathogenesis - slime layer is antiphagocytic
- toxin A- AdP ribosylates EF2
- like diptheria toxin but not as potent

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Other related opportunists related to p. aerginosa

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burkholderia
stenotrophomas
acinetobacter
moraxella

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mycobacterium tuberculosis

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obligate aerobe
- acid fast rods
Tuberculosis, TB, consumption
-major human dx - healthy ppl
- prob -assoc w/AIDS and multidrug resistance

transmission - man- man via airborne droplets

primarily infects lungs but distributed systemically w/in macrophages and survives intracellulary by inhibition of phagosome/lysosome fusion

cell mediated immunity
- infiltration w/macrophages and lymphocytes
- cause granulomas (tubercles)

skin testing
- delayed hypersensitivity w/ tuberculin (protein purified derivative PPD)
- positive test doesn't indicate active dx - just exposure to organism = x-ray

mycobactin - a siderophore

cord factor - damages mitochondria

diagnosis - acid fast bacteria in sputum
- cultured grow slowly producing distinct non-pigmented colonies after 2+ weeks
- differentiated from other mycobacteria by production of niacin
= PCR for rapid diagnosis

tx - extensive time periods - 9 mo or longer since organism grows slowly and may become dormant
- 2 + abx (rifampin and isoniazid, ethionamide, ethambutol) - minimizes possibility for resistance

vaccination - BCG vaccine - attenuated strain of M. bovis - not effective
in US low incidence
vaccination not practiced, immunization interferes w/diagnosis

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M. avium - M. intracellulare complex

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rarely infects man
now recognized as leading bacterial opportunists assoc w/AIDs

multiple drug resistance

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M. leprae

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causative agent of leprosy
in 3rd world

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M. bovis

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zoonotic cause of TB
rarely seen in US b/c erradication of infected catal and pasteurizaiton of milk

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TB and drug resistants

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multiple drug resistant
- resistant to all first line dx
extremely drug resistant
- resistant to some of second line drugs
- nearly untreatable

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mycobacterium leprae

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causative agent of leprosy (Hansen's dx)

chronic dx leads to disfigurament
rare in Us common in 3rd world
- effective abx therapy recently initiated - incidence way down

infects skin, because it growth at low temp - ulcers, resorption of bone, worsened from careless use of hands b/c of nerve damage
- strong affinity for nerves

tuberculoid - few organisms
- active cell mediated immunity

lepromatous l- many organisms
- immuno-suppression by organism

carried in armadillos and mouse footpads

IDed
- lepromin used in skin testing
- acid-fast strains - skin biopses

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mycobacteria and AIDS

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M. avium - much less virulent than M. tuberculus
- doesn't infect healthy ppl just AIDS pt
- when CD4 count is greatly decreased

M. tuberculosis
- infects both healthy ppl and AIDS pts
- earlier stage of dx than M. avium and more symptomatic
- systemic dx more common than just pulmonary
- lesions often lepromatous = non-granulomatous

tx- w/abx
m.avium involved need long term regimeno f multiple drug regimins - b/c doesnt always respond to same abx as M.tuberulosis

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other species of mycobacterial

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infect occasional immuno-compromised host
not transmitted man- man

presnece or absence of pigment
slow or fast growth rates - "RUnyon groups"

cellular FA profiles
mycolic acid profiles
genetic markers

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mycolic acids

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mycobacteria
- longest chain length
- strongly acid fast

nocardia
- intermediate chain length
- weakly acid fast

corynebacteria
- shortest chain length
- not acid fast

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Corynebacterium diptheriae

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gram positive rod
strict aerobe
pleomorphic - club shapped

member of normal flora of pharynx - less common on skin
- overgrowth upper respiratory tract
- pseudomembrane - formed locally can cause chocking
- bacteria do not spread systemically
- toxin disseminates exotoxin- diphtheria toxin - over a period of a week = systemic and fatal injury
- B binds to host cell
- A inhibits prot syn
- ADP ribose moiety (NADH) attaches to a rare AA diphthamide present in EF2
- EF2 inhibited
- not syn if iron present - iron-repressor complex forms - inhibits expression of tox gene
- receptor common in cells of heart and lung - those sites particularly affected

thick gray coating over back of throat - eventually expand down airway and if not tx die from suffocation

tx - anti- toxin
non immune - injection of abx
gene for toxin on bacteriophage - tox gene

corynebacteria not infected w/phage do not cause diptheria

immunization - rare dx - still in normal flora - carrier state - if stop vaccinating it will come back
- immunity monitored w/ Schick skin test - ability to neutralize toxin

identified on Loeffler's medium
- stain for polyphosphate granules - polyphosphate granules (babes-ernst bodies ) - pink
- rest of cell = blue
- metachromatic

tellurite agar - black colonies from ppt of tellurium on reduction by bacteria

exotoxin production - in vivo, in vitro

should not be confused w/ diphtheroids
- other corynebacteria
- propionibacteria
- found in normal flora

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legionella

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- facultative intracellular pathogen
- gram negative rod
- req specialized media to grow - cysteine = charcoal yeast extract agar
- stains poorly w/gram stain
- transmitted via contaminated aerosols
- no person to person transmission

first discribed outbreak of pneumonia among group of legionnaires at convention

another flu-like form - pontiac fever

ubiquituous aquatic sprophyte causes epidemics and sporadic infections

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Legionella of clinical importance

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legionella - one genous - 50 species
- 1/2 of specidees implicated in human dx

1. legionella pneumophilia
- 90% of all cases of legionellosis
- majority of all confirmed cases caused by serogroupw 1-6

2. legionella micdadei
- most common after L. pneuophilia
- stain weakly acid fast on primary isolation but loses this property when grown in vitro = NO RELATIONSHIP TO MYCOBACTERIA

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microbiology of legionella

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will not grow on standard sheep blood agar

grows on buffered charcoal yeast extract agar (BCYE)
1. L-cysteine essential for growth
2. so is iron

colonies are small w/ground glass appearance - 1-3 mm

poorly staining w/ gram stain
slender rods

Growth conditions
1. 35 degrees C
2. 3-7 days

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laboratory diagnosis of legionella

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1. culture from norm sterile tissues

2. detection of L. pneumophilia Ag in urine - only valid for serogroup 1 organisms (good for community infections b/c it is the one responsible for the majority of these cases - not so good for nosocomial)

3. seroconversion - 4 fold or greater rise in specific serum antibody titer L. pneumophilia

4. direct fluorescent antibody staining

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legionnaires Dx

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worldwide - sporadic, epidemic community-acquired pneumonia, and nosocomial infections

exposure - stagnant water
- water based aerosols
- air conditioning cooling towers,
- whirlpool spas
- sauna or mister
- hot water towers

a nationally notifiable dx

clinical presentation - 2 distinct clinical dx
1. legionnaire's dx
- incubation period 2-10 days
- pneumonia
- 15-75% mortality
- erythromycin

2. Pontiac fever
- incubation period 1-2 days
- flu like
- milder - no mortality
- self limiting

pathogenesis
- phagocytosis into monocytes - binding to complement receptors
- inhibit phagolysosome fusion
- replication w/in phagasome
- lysis of the phagosome leads to apoptosis and release of the organism
- sensitized TH1 cells and IFN- gamma crucial for elimination of legionellae
- humeral immunity little effect

surivivval - environment
- amoebae - intracellular agent
- biofilms

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Bordetella

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strict aerobe
gram neg
small cocobacillus - singly or in pairs
transmission by aerosolized droplets
non invasive
strictly human pathogen

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Bordetella of clinical importance

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1. bordetella pertusis - whooping cough - most common pathogen in this genus
- toxin mediated

2. bordetella parapertusis = milder form of whooping cough or subclinical - mild pharyngitis

3. bordetella bronchiseptica = resp dx in dog = kennel cough, swine and lab animals
- rarely causes human dx but can cause bronchiopulmonary symptoms in severly immunosuppresed

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microbiology differentiation of bordetella

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1. growth characteristics
a. B. pertussis
- doesn't grow on common labatory media
- bordet-gengou agar - hemolytic
- nonmotile coccobacillus
- oxidizes AA
- slow growing
- strictly aerobic
0 extremely small


B. parapertussis and B. bronchioseptica
- grows on common labortory media
- sheep blood agar
- urease
- MacConkey agar
-doesn't ferment carbs
- differentiate these two by
Parapertusis doesn't have oxidase or motility where bronchioseptica does

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Diagnosis of bordetella

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sx are characteristic
labatory diagnosis by nasopharyngeal secretions
- culture on bordet-gengoumedium
- incubation for 10-14 days
- grows sml transparent hemolytic coloniese on agar w/blood
- slow growth rate makes direct fluorescent Ab testing on nasopharyngeal specimens a good diagnostic tool
- PCR if avaliable sensitive and specific
-slide agglutination w/specific Ab also used

serologically B. pertusis distingusihed from B. parapertusis and B. bronchiseptica

after 4 weeks of infections cultures are negative

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Whopping Cough

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B. pertusis

endemic dx in US - periodic epidemics every 3-5 years and frequent outbreaks

most less than a year old

coughing illness lasting at least 2 weeks w/ one of the following characteristics
1. paroxysms of coughing w/inspiratory "whoop"
2. posttussive vomiting w/no other apparent cause

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progression of whooping cough

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aerosol droplets access via inhalation -> colonizes cilia of resp epithelium
- incubation period 7-10 days
- mild sx - rhinitis
- mild cough
-sneezing
=== catarrhal stage = lasts 1-2 weeks
- propagation of organism increasingly compromises cilliary fn = increased frequency and intensity of sx
- organism can be recovered in large numbers from pharyngeal cultures
- severity and duration of dx can be reduced by abx tx
- pt highly contagious and not very ill
- can be mistaken for common cold
- slight fever less thatn 100.4

- after 2 weeks dx progresses to paroxysmal stage
- characterized by gradually increasing prolonged and paroxysmal coughing
- ends in characteristic inspiratory gasp
- recurs at variable intervals - often every few minutes and interferes w/ oral intake
- swallowed mucus may induce vomiting - resulting in severe dehydration and wt loss
- hypoxia during prolonged attacks may lead to seizure, hypoxic encephalopathy or coma
- leukocytosis

during paroxysmal stage B. pertussis can rarely be recovered and abx have no effect on progress of dx
- mediated by a variety of soluble toxins

cough episodes gradually decrease after 2-4 weeks and pt recovery can take 3-16 weeks = convalescent stage - recovery followed by immunity
complications = pneumonia - due to other bacterial pathogens, otitis media and meningo-encephalitis, anorexia, dehydration

complications from severe paroxysms -
1. pneumothroax
2. epistaxis
3. subdural hematomas
4. hernias
5. rectal prolapse

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pertussis among adolescents and adults

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dx often milder than in infants/kids

infection may be asymptomatic or may present as classic pertusis
persons w/mild dx transmit infection
older persons often source of infection

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pertusis pathogenesis

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2 stages resp colonization - no sx - positive clutures
toxin mediated
- exotoxins - controlled by central locus
- bvs - two component signal transduction system to sense the environment and regulate gene

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colonization of B. pertusis

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mediated by filamentous hemagglutinin and pertussis toxin

filamentous hemagglutinins - not exotoxins - dominant adhesion
- req for tracheal colonization
- highly immunogenic
- primary component of acellular pertussis vaccines
-assoc w/lipo-oligo- saccharides which are involved in the binding of the organism to ciliated epithelial cells

pertussis toxin (pertussigne - AB- type exotoxin - 5 subunits 1 A subnit and 2-5 complex of B subunits
- major cause of abnorm cough
- toxin secretedx into extracellular fluid and cell bound
subunits S2 and S3 also fn as adhesions and bind bacterial cell to host

S1 subunit of pertussis toxin - ADP-ribosyltransferase acts by covalent addition of ADP riobose to the GTP binding Gi protein = prevents deactivation of adenylate cyclase = large amts of cAMP = increase mucus secretion and the disruption of many cellular fns
- causes lymphocytosis - enhanced insulin secretions
increased IgE synthesis
increased histamine production and endotoxin sensitivity
- inhibits mitongenicity for T lymphocytes and inhibits chemotaxis, phagocytosis and resp burst - as well as impairing NK cell killing

Fimbriae
- req for persistent tracheal colonization
- component of ome acellular pertussis vaccines
-req for protective immunity to infection

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Pertussis is primarily a toxin mediated dx

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1. pertusis toxin
2. adenylate cyclase toxin
3. dermonecrotic (heat-labile toxin
4. tracheal cytotoxin
5. lipopolysaccharide endotoxin - like other gram neg bacteria - pyrogenic, mitogenic, can activate and induce TNF production in macrophages

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pertussis toxin

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1. pertusis toxin AB toxin - 6 prot subunits
- binds to ciliated epithelial cell via B subunits
- A acts locally as ADP ribosyltransferase - ADP ribose to membrane bouynd inhibitory GTP binding protein = inhibits adenylate cyclase
= constitutive activation of adenylate cyclase
- S2 binds exclusively to ciliary lactosylceramide
- S3 binds to leukocytic gangliosides
Effects:
1.. T cell lymphocytosis with decreased mitogenicity
2. increased insulin secretion
3. histamine sensitization
4. Increased IgE production
5. impaired phagocyte fn
6. ADP -ribosylates G proteins
7 strong adjuvant

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adenylate cyclase toxin of B. pertussis

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exotoxin acts locally to inhibit phagocyte and NK fns
- inhibits superoxide generation and induces apopiosis of macrophages
- helps the organism initiate infection

only active in presence of calmodulin

catalyzes conversion of ATP -> cAMP

orginally ided as hemolysin - lysed RBC
increase in cAMP caused by this is short lived

secreted invasive toxin

directly penetrate human phagocytes and binds

pore forming toxin

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dermonecrotic heat labile toxin of B. pertusis

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causes inflammation and local necrosis adjacent to sites where B. pertussis is located

very strong vasoconstricter

causes extravasation of leukocytes

in assoc w/tracheal cytotoxin causes necrosis of tracheal tissue

activates Rhao

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tracheal cytotoxin of B. pertusis

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PG-like molecule binds to ciliated epithelial cells, preventing the ciliated cells from beating - ciliostasis

disaccharide tetrapeptide monomeric by product of PG syn

increases IL-1 and nitric oxice production

virulence factor not reg by bvg

causes extrusion and destruction of ciliated epithelial cells

destruction contributes to sx

extrusion leads to mucus plugs -= pulmonary obstructions - atelectasis

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Type III secretion system of B. pertusis

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allows Bordetella to translocate effector proteins directly into host cells
req for persistent tracheal colonization
inhibits host immune response
induces necrotic cell death

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pertussis tx

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erythromycin
vaccine - killed bacterial cell suspension DTP vacccine
immunity wanes after 5-10 years

multicomponent acellular vaccine - contains pertussis toxoid, filamentous hemagglutinin and the 2 types of fimbriae

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Haemophilus

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- small- short - pairs or short chains
- non-motile
- pleiomorphic
- gram neg
- coccobacilli
- growth culture req:
1. exogenous hemin (oxidized ferroprotophorphyrin) ( X factor)
2. nicotinamide adenine dinucleotide NAD ( V factor)

- transmitted via resp droplets or direct contact w/contaminated secretions
- normal flora of human resp tract and oral cavity

H. influenzae most common pathogen

H influenzae type b polysaccharide capsule - most virulent

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haemophilus species of clinical importance

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1. type B. H. influenza
- meningitis
- epiglottitis
- bacteremia
- cellulitis

2. non typable H. influenzae
- otitis media
- sinusitis
- tracheobronchitis
- pneumonia

3. H. parainfluenzae
- pneumonia
- endocarditis

4. H. aphrophilus
- pneumonia
- endocarditis

5. H. ducreyi
- genital chancre - STD

6. H. aegyptius
- conjunctivitis
- brazilian purpuric fever

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haemophilus - species identification

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- small faintly-staining gram neg coccobacillus filamentous rods

- grow on choclate agar

- does not grow on 5% sheep agar - only around colonies of S. aureus - satellite phenomenon

- growth w/ 5% CO2 is enhaced

- X and V factor requirements using X, V, and XV factor impregnated paper strips on mueller-hinton agar

H. influenzae - req X and V
H. aegyptius - req X and V
H. ducreyi - req only X
H. parainfluenzae - req only V
H. aphrophilus - req neither one

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HH. influenzae

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IsoVitaleX -enriched choclate agar
- req 2 erythrocyte factors for growth - X (hemin) adn V (NAD)
- 5% CO2 enhances growth
- flat grayish brown colonies

- strains are divided on the basis of capsular polysaccharides (a-f) or the absence of a capsule - non typabpe)
- type b capsule composed of polyribose-ribitol phosphate (PRP)

diagnosis - culture - culturing and isolating bacteria from normal sterile body site
- serotype testing - distinguishes encapsulated strains from unencapsulated strains
- Ag detection - type b capsular ag can be detected in urine, blood, and CSF

- 95% of invasive dx caused by type b
-carrier rate for type b 2-4%
carrier rate for non-typabable 50-80%

-type b colonizes the nasopharynx
- nontypable colonizes nasopharynx, trachea, and bronchi
- lipooligosaccharide largely responsible for inflamation
- colonizes healthy kids and adults - spread by direct contact, secretions or aerosols
- invasive H. influenzae dx is a nationally notifiable dx

resp infections w/nontypable H.influenzae are assoc w/underlying cond (SF, COPD, malignancy

type b - mild upper resp dx (runny nose, low grade fever, and headache) -> followed w/in 1-3 days by meningitis -> invasive org enters circulation and crosses BBB - rapidly progressiong - death - timely tx
-could also cause septic arthrits, cellulitis, pneumonia, and epiglottitis (obstruction of airway and suffication)

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H. influenze immunization

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vaccine is the b capsular polysaccharide - polyribosyl-ribitol-phosophate PRP covalently bound to tenanus toxoid

incidence falledn 99% post vaccine

pre immunization - serotype b most common invasive species

post -immunization
- most cases in unvaccinated or incompletely vaccinated kids
- non-encapsulated and serotype f are most common ( septic arthritis, osteomyelitis, cellulitis, pericarditis,, pneumonia)
- kids - pneumonia and meningitis less common
- most infections ~2/3 are attributed to nontypeable strains

- S. pneumoniae - otitis eida and then nontypable Hi most common
- sinusitis, chronic bronchitis, and purulent bacterial conjunctivitis

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H. aegyptius

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unecapsulated
invasive infections :
- purulent conjuctivitis (Mortality up to 70%)
-

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H. parainfluenzae

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low virulence w/sporadic cases of endocarditis and bacteremia

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H. aphrophilus

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uncommon cause of subacute endocariditis and brain abcesse

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H. influenzae pathogenic mechanism

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1. encapsulated organisms penetrate the epithelium and invade blood capillaries directly

2. antiphagocytic polysaccharide capsule is major pathogenesis factor

3. LPS lipid A comonent of cell wall (major role in non-capsule strains)

4. all virulent strains produce neuraminidase and IgA protease
-no exotoxins

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H. influenzae tx

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abx for type B meningitis and epiglottitis
- cefotaxime sodium OR
ceftriaxone sodium OR
ampicilin
- in combination w/chloramphernicol

3 Hib conjugate vaccines availible in US

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H. ducreyi

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extracelluaar pathogen

major cause of huma genital ulcer dx - chancroid in dev countries - Asia, africa, latin america
less common in US
- assoc w/ sexual transmission of HIV virus

presents as single or multiple painful necrotizing ulcers at site of infection - accompanied by painful swellling and suppuratiion of regional LN
- lesions are usually not indurated
- males =- most ulcers found on prepuce near frenulum or in coronal sulcus
- infection generally asymptommatic in women but most lesions are found at entrance of vagina

inculbation 3-14 days after exposure
- followed by a tendure papule that becomes pustular then ulcerates over the course of 2 days
papular stage 0 tender papule - tiny erythematous zone - 4-7 days post exposure
pustular stage - lesions on prepuce, fraenulum, glans or anus in men, vulva, cervix or perianal are a in women
- ulcerativve stage- ruptures - irregular ulcer w/many projection and depression
- yellow or grey purulent exudates that bleeds easily
w/o tx = chronic take up to 3mo to heal

fastidous organism and lab diagnosis made by isolation from exudates and serology
- strained smear shows gram neg short rods in parallel row of sml rods in chains

incidence in 2--5 17 cases

pathogenic factors - PG assoc lipoprotein, adhesive pili, and cytolethal distending toxin

Abx = axithromycin, ceftriaxone, ciprofloxiacin, or erythromycin cure it

Complications
- phimosis - inability to retract distal foreskin
- deep, necrotic and gangrenous skin ulceration due to secondary bacterial infection
- unilateral lymphadenopathy 50% of cases
- affected LN may become tenter and painful buboes
- buboes may rupture and form inguinal ulcers

hard to culture
only req factor X on choclate aggar 33 deg C w/5% CO2

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H. aegyptius

Back 327

acute contagious conjunctivitis - pink eye

brazilian purpuric fever in children
- high fever
- hemorrhagic skin lessions
- septicemia
- vascular collapse
- hypotensive shock
- death w/in 48 hrs



AKA Koch-Weeks bacillus
- non encapsulated invasive organims

Front 328

H. aphrophilus

Back 328

normal flora of oral and resp tract - organism can cause endocarditis and pneumonia

slow gorowing - blood cultures for 2 weeks - clinical suspicion of endocarditis w/neg blood cultures after standard 5 days

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HACEK organisms

Back 329

H- haemophilus aphrophilus
A = actinobacciluus actinomycetemcomitans
C = cardiobacterium hominis
E - eikenella corrodens
K = kingella kingae

Front 330

zoonosis

Back 330

dx primarily of animals which can be transmitted to humans as a result of direct or indirect contact w/infected animal populations

Front 331

brucella

Back 331

primarily a dx of animals

common where significant dx among domestic animals

predilection for organs rich in erythritol - breast, uterus, placenta, epidiymis - - causes infertility, sterility, mastitis, abortion, or carrier state in non-human animals

common names = undulant fever
malta fever
mediterranean remittent fever

can go through intact skin

faculative intracellular bacteria

unpasturized cheesses from areas of high risk - particular risk for tourists

2 types of ppl get it
1. ppl in close contact w/infected animals (slaughterhouse, workers, vets, farmers, dairy workers) - direct contact or inhalation - b. abortus and b. suis
2, ppl who ingest unpasteurized dairy products contaminated w/brucella - B. melitensis

4 diff species infect human
B. abortus (cattle)
B. suis (swine)
B. melitensis (goats/sheep)
B. canis (dogs)

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morphology and physiology of brucella

Back 332

poorly staining sml gram neg coccobacillus
grows slowly 7 days at 37 deg C

on subculture - min og 48 h growth

aerobic growth on choclate agar and sheep blood agar

WILL NOT GROW on MacConkey or Eosin methylene blue agar

apoears mostly as single cells and look like fine sand

nonhemolytic and nonmotile
strict aerobs except some strains of B. abortus req 5% CO2 on primary isolation

catalase, oxidase, and ureased positive
- urease test suseful for characterization

B. suis and B. melitensis strains produce a rapid rxn that can be observed w/in 5 min of inoculation on a Christensen's urea slant - other species positive rxn after overnight

B. melitensis colonies - slowly growing on standard lab media 0 -usually not visible at 24 hr - pinpoint, smooth, translucent non hemolytic at 48 h

Front 333

epidemiology of brucellosis

Back 333

all US Puerto rico and virgin islands - free of bovine brucellosis - B. abortus
- enzootic in elk and bison in the greater yellowstne national park area

49 statse free of swine brucellosis B. suis
- Texas
- enzootic in feral sqine in SE

100- 200 cases seen in US - worldwide more

2010 -= total of 115 cases
- california 26 cases
- florida and arizona 9 cases each

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Human brucellosis

Back 334

sx can appear up to 2 mo after exposure

acute phase -
< 8 weeks from illness onset - pt presents w/nonspecific and flu-like symptoms
- including - fever - intermittent (undulant)
- sweats
- malaise
- anorexia
- headache
- myalgia
-back pain
- chills
-fatiuge
-wt loss
- arthralgias
- non productive cough

Advanced dx <1year after onset
symptoms
- undulant fever
- arthritis
- epididymo-orchitis in males

chronic dx > 1year from onset
- mimic miliar TB w/ suppurative lesions in liver, spleen and bone
- recurrent fevers
- arthritis
- depression
-chronic fatigue syndrome
- may lead to gramulomatous hepatitis
- peripheral arthritis
- leucopenia
-thrombocytopenia
-meningitis
- endocarditis

depends on organism
B. abortus - mild suppuurative febrile infection - complications rare

B. canis - mild suppurative febrile infection - complications rare

B. suis - prolonged dx which may lead to the formation of destructive lesions in the lymphoreticular organs and kidneys

B. melitensis - severe recurring dx - high incidence of serious complications

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pathogenesis of brucella

Back 335

survives as facultative intracellular pathogens w/in reticuloendothelial system

following penetration of mucosal epithelium - inhalation/ingestion routes, abraded skin or conjunctiva
-> bacteria transported via macrophages to regional LN = acute lymphadenitis
- inhibits myeloperoxidase -H2O2 halide antibacterail system in neutrophils hampering degranulation

in Macrophage inhibits phagosome lysosome fusino allowing bacteria to survive and multiply
- systemic spread and multiplication of brucella in LN, spleen, liver , BM, mammary glands, and sex organs via macrophages
_> once migrate to other organs - form granulomas and/or micro abscesses
- ability of survival in macrophages resp for est of chronic infection
DONt produce exotoxins

LPS doesn't activate the alternative complement pathway


pot bioterroirist agent

Front 336

diagnosis of brucella

Back 336

symptoms - undulant fever, myalgia, athralgaia

history - contact w/animals or consumption of unprocesed
material from infected animals

serological agglutination tests - serrological testing SAT - 4 fold rise in SAT titer btw acute and convalescent phase

culture - culture positive blood, bone, tissue, or abcess fluid - fastidious organisms grow very slow

Front 337

prevention and tx of brucellosis

Back 337

tx = tetracycline, doxycycline or trimethoprimsulfamethoxaxole in combo w/rifampin or gentamicin for 6 weeks

control via animal vaccination and avoidance of infected materials

Front 338

Francisella tularensis

Back 338

Tularemia

primary reservoirs are rabbits, deer, and rodents (in US rabbits and muskrats)
- isolated from over 100 wild animals
- humans acquire via insect bites ( primarily ticks but also deaer flies, mites, black flies or mosquitos
- or by handeling infected animal tissue, inhalation of aerosols , or ingestion of contaminated food or water = exposure in lab settings

gram neg coccobacilli
- low infectious dose 10-15 bacilli will cause dx in humans if inhaled or introduced intradermally but very large doe for oral route of infection
- 2 species F. tularensis - type A and Type B
- nonmotile
-encapsulated
- pleomorphic cocobacillus (short rod)
- grows poorly on most lab media
-requires glucose and cysteine for isolation
- will grow on choclate agar and buffered charcoal yeast extract agar
- aerobic - slow growing 48 hr at 35-37 degrees
- colonies very small white to gray to bluish gray
-req sulfhydryl (cysteine, IsoVitaleX) supplementation for growth
- won;t grow on MacCFonkey or EMB plates
- oxidase negative
-weakly catalase positive
- urea negative
- nitrate negative
0 beta lactamase positive
- satellite or XV test negative - unlike Haemophilus

endemic in US
- majority of cases occur May- September
- mostly in rural areas
- 124 cases in 2010 - ark 19, missouri - 18, kansas - 16

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Tuleremia

Back 339

incubation period 3-10 days w/ range of 1-21 days
clincal manifestation divided into 5 groups
1. ulceroglandular form - most common (45-85%)
- painful ulcerating papule which has necrotic center and raised periphery develops at site of infection
- fever
- tender regional lymphadenopathy
- flu like sx (chills, myalgias, malaise, arthralgias, headache, and anorexia)

2. glamdular - w/o ulcer

3. typhoidal - sepsis - bacteriemia
-fever, chills, headache, myalgias, malaise, sore throat, and anorexia
- distinguished by clinical findings of - high fever
- splenomegaly
-hepatomegaly
- commonly also have assoc GI and pulmonary sx as well s typical flu like sx
- can result from pulmonary or GI tularemia
-likely bioterrorism presentation

4. pneumonic - results from exposure to aerosolized particles of F. tularensis - hematogenous spread
- pt often present w/ community acquired atypical pneumonia nonresponsive to conventional abx therapy

5. oculoglandular
- inoculation of the conjunctiva
- unilateral, purulant conjunctivitis
- perauricular, submandibular or cervical lymphadneopathy

6. oropharyngeal/GI - ingestion of infected meat or water
- primary dx confined to throat

assoc skin/mucous membranes and assoc lymphadenopathy

pneumonia is a complication in 30% of pts w/ulceroglandular tularemia and 80% of pts w/typhoidal tularemia

recovery and perminent immunity

Front 340

Pathogenesis of tuleremia

Back 340

facultative intracellular pathogen

capsule protects against complement killing

macrophage uptake
- bacterial surface polysaccharides
- serum complement
- complement C3 receptors

- LPS - O - Ag
- prevents maturation of phagosome

-multiply to high levels in cytosol
-bacterial release via apoptosis

Front 341

diagnosis of tuleremia

Back 341

Sx and history
difficult to visualize in direct smears by gram stain - but direct fluorescent antibiody staining will improve visualizaiton
- LN aspirates and sputum are cultured on chocolate agar or vuffered charcoal yeast extract agar - culture in cystein rich media

blood cultures often neg

serum ab titers of 1:160 or greater

notify lab personell if u suspect it b/c highly infectuous

grows vbery slowly - incubated for several days

serum ab testing most common

Front 342

tx of tuleremia

Back 342

streptomycin
gentamysin = alternative

live attenuated vaccine available but not completely effective
- avoid handeling infected animals watch for ticks and utilize clean water supplies

Front 343

Yersinia

Back 343

3 strains cause human dx
Y. pestis
Y. enterocolitica
Y. oseudotuberculosis

Y. enterocolitica and Y. pseudotuberculosis = severe gastroenteritis

Y. pestis = plague

Front 344

Y. pestis

Back 344

- pleomorphic
- gram neg - bipolar staining
- faculative anaerobic
- optimal temp is 28 degrees C
- Grows well on standard labatory media - Sheep blood agar - non hemolytic
- non motile
- oxidase and urease ngative

single cells or short chains of plump gram neg rods
gram stain - in direct smears bacteiral cells may be inside or outside leukocytes
- gram spear morphology is suggestive but not specific for Y. pestis
- bipolar staining occurs when using Wayson or giemsa
staining

colony characteristics - on sheep blood agar - gray-white translucent colonies
- pinpoint, gray-white, non-hemolytic at 24 hrs

Front 345

Plauge

Back 345

Y. pestis - appear as single cells or short chians or clumps of gram negative rods
3 forms of clincial illnes
- Bubonic
- Septicemic
- Pneumonic - only one transmitted through aerosols

natural dx of rodents- fleas that live on rodents transmit the bacteria to humans in bubonic form - carried in fleas intestinal tract when feeding they regurgitate uncapsulated organisms - bacteria re-encapsulate and grow


dx occurs in many areas of the world including US 2010 - 2 cases both in organ
- endemic in desert southwest
- animal (sylvatic) plague occurs in number of western states in sml rodients or carnivors that feed on them
- most cases occur in summer
- human cases ( urban plague) - generally spread through rats

incubation period of 2-7 days then sx appear - bulk of non-capsular org are phagocytosed and destroyed by neutrophils
- few taken up by monocytes unable to kill them and org resyn their capsule and multiply
- encapsulated org when released from monocytes are resistant to phagocytosis and killing by neutrophils
- resulting infection spreads to the draining LN which become hot, swollen, tender, and hemorrhagic - fiben rise to the characteristic black buboes - bubonic plague

- inguinal, axillary or cervical Ln most common - grossly swollen and sore - Septicemia will occur in 80% of pts

Organism spreads to spleen, liver and lungs resulting in pneumonia

while in circulation organism causes diffuse coagulation resulting in intravascular thrombi and purpuric lesions all over body
-if untx infections has 90% mortality
- org are exhaled in cough droplets - infect other humans in close proximity and cause pneumonic plauge whcih is more difficult to control and has 100% = pneumonia progresses rapidly to dyspnea, cyanosis
- death from resp collapse/sepsis
80% become septic

pathogenic factors - exotoxins paly direct role

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septicemic plague

Back 346

primary or secondary
- secondary from bubonic or pneumonic forms
- 100 % mortality if untx

- severe endotoxemia
- systemic inflammatory response syndrome
- shock, disseminated intravascular coagulopathy (DIC)
- adult resp distress syndrome

Front 347

Y. pestis virulence determinants

Back 347

3 virulence encfoded plasmids
- virulence is up -reg at 37deg C
- capsule F1 ag

Yersinia outer proteins (Yops)
- 11 diff prot encoded by palsmids
- essential for pathogeneiss
- antiphagocytic
- inhibit producition - proinflammatory cytokins
- tumor necrosis factor
-cytotoxin
- inhibition of platelet aggregation
- inhibit phagocyte migration and engulfment
- target dendritic cells, macrophages, and neutrophils but do not affect T and B lymphocytes

Envelope F-1 Ag
- glycoprotein capsul expressed at 37 deg C
- not expressed in flea host
- anti phagocytic
-Ab to F1 are protective

Plasminogen activator (fibrinolysin) = plasminogen activator - fibrinolysis - promotes the dissemination of the organism
- plasmid encoded proteins
- copagulase too - coagulase produced at 28 degres but not 32 degrees

Front 348

diagnosis of plauge

Back 348

based on appearance of buboes
- diagnosis confirmed by culture of LN aspirate
- extreme caution warranted in handling the specimen - highly infectious
- grows well on most standard lab media
- fluorescent ab testing available

Front 349

plague tx

Back 349

susceptible to a variety of abx
- streptomycin
- tetracycline
- doxycycline

- pneumonic plague contageous and isolation recommended

- an effective formalin killed vaccine available but recommended only for ppl at high risk
-dx is internationally quarantined - and reporting of cases is mandetory
- control of urban plague is based upon flea and rodent control

Front 350

Listeriosis

Back 350

nationally notifiable dx

listeria - 6 species only 1 of which is a human pathogen
- L. monocytogenes (human pathogen)
- caused by the ingestion of contaminated foods resulting in an acute febrile gastroenteritis

in pregnant women - spontaneous abortiona and mild flu like illness

neonatal dx - contracted transplacentally or during delivery

can cause meningitis and sepsis in the elderly and immunocompromised

3 categories of listerosis
1. adult dx
2. dx in pregnant women
3. fetal dx

in normal adult
- acute febrile gatroenteritis
sx - body aches
- fever and chills due to bacteriemia
- headache
- n/v
- watery diarrhea
- pain in joints and mm

illness 24 hr after ingestion and usually lasts 2 dyas

considered possible etiology in outbreaks of febrile gastroenteritis when routine cultures fail to yield pathogen

- one of the leading causes of bacterial meningitis in pts w/cancer and renal transplant recipients

elderly- sx may go unnoticed = bacteremia high fever hypotension - sepsis - > endocarditis

neonatal can occur in two forms
- in utero - acquired infection - granulomatosus infantiseptica - abcesses and granulomas in multiple organs -> results in abortion

post delivery - 2 presentations
- early onset - w/in first 5 days after exposure on vaginal delivery and is assoc w/sepsis and meningitis

late onset - occurs btw 5 days -3 weeks after delivery = purulent meningitis or meningo-encephalitis w/sepsis

Front 351

L. monocytogenes

Back 351

gram positive coccobacilli in pairs or short chains

- facultative anaerobe

- facultative intracellular pathogen

- motile (end-to-end tumbling at 25 deg not 37 degrees

- weak beta-hemolytic on sheep blood agar

- can grow and replicate at 4 degree C and high salt concentration
-- grow at low temp - common means to select for it

Front 352

cources of listeriosis

Back 352

humans can be intestinal carriers 1-5%

found in feces of mammalian, avian, fish and crustacean species

isolated from soil, silage and other enviro sources

food sources raw veggies, unpasteurized milk, soft cheese, and meats

nosocomial transmission - neonatal nurse

Front 353

pathogenesis of listeria

Back 353

internalins
- InlA resp for uptake into epithelial cells and req for crossing the intestinal and placental barriers
- InlB mediates entry into a variety of cell types and plays a role in invading human placenta in conjunction w/InlA

organism binds to E-cadherin on non-phagocytic cells via InlA = taken up into phagolysosomes
- low pH environment activates listeriolysin O (beta hemolysin - virulent strain only, oxygen labile, antigenic, disrupts phagosome) an exotoxin and 2 phsopholipase C enzymes
- phsophatidylinositol specific phospholipase C
- lecithinase (phosphatidylcholine phospholipase C)
- bacteria released into cytosol
- once in cytoplasm bacteria undergoes rapid division and becomes encapsulated by short actin filaments that reorganize into a long tail extending from only one end of the bacterium - facilitates movement to surface of cell

at cell periphery protrusions - filopods are formed that can penetrate neighboring cells and allow bacterium to move int o adjacent cells

readily killed by activated macrophage

Front 354

diagnosis and tx of lissteriosis

Back 354

indicated when blood and CSF monocytes observed - org isolated on most lab media
- isolation of org from blood or spinal fluids

tx - penicillin (ampicillin) or in combo w/gentamycin

Front 355

erysipelothrix rhusiopathiae

Back 355

Infection is occupationally related
Fishermen
Butcher
Veterinarians
Contact with animals, their products or wastes
Three types of human infection:
Localized cutaneous
Generalized cutaneous
Septicemic which is associated with endocarditis

Gram positive
Microaerophillic bacillus
Thin, pleomorphic
Non-motile
Non-encapsulated
Non-sporulating

Grows well on most laboratory media.
After 48 hours colonies are small to pinpoint.
Colonies are non-pigmented and transparent.
The α-hemolysis will develop after two days

Front 356

sources of erysipeliod

Back 356

Acquired through skin abrasions
Inflammatory violaceous lesion at the infection site (usually fingers or hand)
Lesion is pruritic and painful
Lesion is non-supporative
. It lacks suppuration and thus is distinguishable from staphylococcal erysipelas

Front 357

erysipeloid of hand

Back 357

Well-demarcated, violaceous, cellulitic plaque
No scales or vesiculation
Occurred following cleaning fish
The site was somewhat painful, tender, and warm.

. Erysipeloid is an inflammatory skin lesion (cellulitis), on fingers or hand. After 2 to 7 day incubation period lesions develop which are well-defined, slightly elevated, with a violaceous zone which spreads peripherally as discoloration in the central area fades. The pain is severe and may be described as a burning, throbbing, or itching sensation

The infection will resolve in 3 to 4 weeks without antibiotic treatment and sooner if antibiotics are administered. Systemic effects are uncommon.

The diffuse cutaneous form is rare. The cutaneous lesion progresses proximally
from the site of inoculation or appears in other areas. Blister formation may occur. The patients often have systemic manifestations such as fever and joint pains, but blood cultures are negative. The clinical course is more protracted, and recurrences are not uncommon. Systemic E. rhusiopathiae infections are infrequent.
.
The virulence factors include hyaluronidase and neuraminidase.

Front 358

diagnosis and tx of erysipeloid

Back 358

The organism can be isolated from biopsy or tissue aspirates. The organism is not fastidious and can be grown in nutrient broth. Subculture on blood agar yields small α-hemolytic colonies.

Treatment and control: Erysipeloid is easily treatable with penicillin, but inherently resistant to vancomycin.

Front 359

bacillus

Back 359

2 species cause human dx
B. antrhacis - bioterrorism
B. cereus - assoc w/ production of grains particularly rice

aerobic
gram positive rods
spore forming

present in soil

Front 360

Antrhax

Back 360

bacillus antrhracis

spores formed in culture, soil and tissues and exudates of dead animals
BUT not in blood or internal tissues of living animals

spores remain viable for extremely long periods - 50 years

transmission by contact w/infected animals or contaminated animal products ( working w/hides, wool, bone meal, by inhalation of spores( Woolsorter's dx) or by inggestion of diseased animals

primarily dx of cattle, sheep and goats

no person-to-person transmission of inhalation anthrax

NOt an invasive dx

3 distinct clinical presentations
- cutaneous - most common
- gastrointestinal = not major form of bioterrorism attack but cannot be dismissed
- pulmonary = route of chose for bioterrorism attack

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cutaneous anthrax

Back 361

accounts for more than 95% of human cases

spores enter through breaks in the skin, germinate and rapidly proliferate at the portal of entry

incubation - hours to 7 days

w/n a few days a papule emerges and becomes vesicular - sml itch raised area - ulcer surrounded by blister like lesion 24-48 hrs

rupture of this lesion - black eschar (painless ulcer) at the base surrounded by a zone of induration but no pus or pains are assoc

lesion is referred to as malignant pustule

lesion classically found on the hands, forearms or head

invasion of bloodstream leads to systemic dissemination of bacteria

profound edema around lesions

death 20% untreated; rare if tx

Front 362

pulmonary anthrax

Back 362

inhalation of B.antrhracis spores - phagocytized by alveolar macrophages where they germinate and replicate

the organisms released from dying cells and infect hilar LN -> marked hemorrhagic necrosis

fever, malaise, myalgia, and nonproductive cough

once in hilar LN may diseminate

respiratory disstress and cyanosis are manifestations of toxemia

death w/in 24 hrs from anthrax - significance in biol warfare

inhalational - incubation 1-6 days but can be as long as 43 days
gradual onset 1-6 days
- fever, nonproductive cough, mm pain, malaise

short period of improvement
abrupt dev of severe resp distress = dyspnea, diaphoresis, stridor, cyanosis, shick and death usually occur w/in 24-36 hr after the onset of resp distress

- mortality rate 100% despite aggressive tx

Front 363

gastrointestinal antrhax

Back 363

ingestion of meat derived from an infected animal - proliferation w/in GI tract, invasion of epithelium, and ulceration of the mucosa

organisms invade the mesenteric LN and desseminate into blood

initially vomiting and diarrhea followed by blood in feces
invasion of blood - profound prostration, shock and death

not seen in US

Front 364

culture characteristics of B. antracis

Back 364

incubated 35-37deg

cultures examined w/in 18-24 hrs of incubation

growth may be observed as early as 8 hrs after inoculation

grows well on sheep blood agar NOT on MacConkey agar

at 15-224 hrs isolated colonies are 2-5 mm
nn-hemolytic nonpigmented
- b.cerus is hemolytic

vegetative cells are in short chains 2-4 cells that are encapsulated
- large gram-positive rod
- capsule can be visualized microscopically using India Ink
- appear as a well-defined clear zone around the cells
- sproes are not generally present in clinical material
- CO2 levels w/in the body inhibit sporulation
- spores may be seen in material from wound eschars but not in body fluids

oval, central-to subterminal spores - green ovals

isolated from blood specimens - may be enough org in blood to see them on direct smears by gram stains
- appears as short chains of 2-4cells which may be encapsulated

swab specimens for cutaneous antrhax
sputum specimens
CSF specimens
nasal swabs NOT used to diagnose not accurate indication of dx

Front 365

Pathogenic mechanisms of B. antrhracis

Back 365

exotoxins
- plasmid encoded (pXO1)
- 3 components
1. protective Ag - fns as a ligand binding to surface receptor - antrhax toxin receptor is a type I membrane protein w/an extracellular von willebrand factor A domain - once bound the protective ag is cleaved into 2 fragments by cellular protesases (furin) - larger fragment self assoc into ring shaped heptomers that binds up 2 3 molecules of edema factor and or letal factor - complexes endocytosed and trafficked to endosomes - low ph = conformational changes in PA that allow it to form a membrane spaning pore and translocates bound EF and .or LF across the membrane into cytosol

2. Edema factor - when inside the cells binds to calmodulin and complex acts as adenylate cyclase
- causes dramatic iincrease in cellular cAMP levels = upsetting water homeostasis and destroying the balance of intracellular signaling pathways
- responsible for edema in cutaneous anthrax

3 . lethal factor - zinc-dependent endopeptidase specific for 2 mitogen activated protein kinase kinases(MAPKKs_ - PA + LF inactivates MAPKKs inducing cell deal of macrophages
- 3 protiens individual - no known toxic activity Ab protective against agtigens prevent PA binding to cells and stop EF andLF entry


Capsule
- consists of polypeptide of D- glutamic acid that is encoded by a plasmid and is anitphagocytic
- not a good immunogen and even if any Ab produced not protective agianst this
- plasmid encoded pXO2

Front 366

anthrax tx

Back 366

most B.anthracis strains are sensitive to a broad range of abx
- penicillin, ciprofloxacin, or doxycycline

tx should be initiated early
= post exposure tx - start abx early - and stay on them for 60 days b/c cpore persistence in lungs and LN

diagnosis - by direct exmaination or culture - fresh smears of vesicular fluid from under the eschar, blood, spleen or LN aspirates
cultured org - gram positive long thin rods

quarantine NOT needed

current US vaccine approved for ppl 18-65
- 93% protective against cutaneous and may may also be protective against inhalation

approved for 6 dose regimen over 18 months w/yearly boosters
- 3 dose regimen (0,2, and 4 weeks) may be effective for post exposure tx)
- vaccine is a cell free filtrate that contains protective ag and alum
- preg women should not be vaccinated
limited availability

Front 367

B. cereus

Back 367

found in soil
enterotoxin in food or produced in GI tract
colonies are beta hemolytic

dx
1. food poisoning
- 2 types
a. emetic (commonly found in rice)
- n/v abd cramps
- self limiting recovery w/in 24 hrs
- incubation 1-5 hrs
b. diarrheal
- incubation 1-24 hrs
- profuse diarrhea w/abd pain and cramps
- fever and vomiting uncommon

2. eye infections (foreign body trauma) = severe keratitis, endoopthalmitis, panopthalmitis

pathogenesis
- 3 enterotoxins ided
1. hemolysin a tripartite toxin - hemolytic, cytotoxic, dermonecrotic, and vascular permeability activities
2. nonhemolytic enterotoxin a tripartite toxin
- enterotoxic and cytotoxic
3. cytotoxin
- toxin cim to Beta-toxin of clostridium perfringens

Cereulide or emetic toxin - single heat-stable peptide toxin - resembles staphylococcal enterotoxin

tx- symptomatic

Front 368

anthrax tx

Back 368

most B.anthracis strains are sensitive to a broad range of abx
- penicillin, ciprofloxacin, or doxycycline

tx should be initiated early
= post exposure tx - start abx early - and stay on them for 60 days b/c cpore persistence in lungs and LN

diagnosis - by direct exmaination or culture - fresh smears of vesicular fluid from under the eschar, blood, spleen or LN aspirates
cultured org - gram positive long thin rods

quarantine NOT needed

current US vaccine approved for ppl 18-65
- 93% protective against cutaneous and may may also be protective against inhalation

approved for 6 dose regimen over 18 months w/yearly boosters
- 3 dose regimen (0,2, and 4 weeks) may be effective for post exposure tx)
- vaccine is a cell free filtrate that contains protective ag and alum
- preg women should not be vaccinated
limited availability

Front 369

B. cereus

Back 369

found in soil
enterotoxin in food or produced in GI tract
colonies are beta hemolytic

dx
1. food poisoning
- 2 types
a. emetic (commonly found in rice)
- n/v abd cramps
- self limiting recovery w/in 24 hrs
- incubation 1-5 hrs
b. diarrheal
- incubation 1-24 hrs
- profuse diarrhea w/abd pain and cramps
- fever and vomiting uncommon

2. eye infections (foreign body trauma) = severe keratitis, endoopthalmitis, panopthalmitis

pathogenesis
- 3 enterotoxins ided
1. hemolysin a tripartite toxin - hemolytic, cytotoxic, dermonecrotic, and vascular permeability activities
2. nonhemolytic enterotoxin a tripartite toxin
- enterotoxic and cytotoxic
3. cytotoxin
- toxin cim to Beta-toxin of clostridium perfringens

Cereulide or emetic toxin - single heat-stable peptide toxin - resembles staphylococcal enterotoxin

tx- symptomatic

Front 370

bioterrorism

Back 370

intentional or threatened use of viruses, bacteria, fungi, or toxins from living organims to produce death or dx in humans, animals, or plants

Front 371

why biological attacks

Back 371

1. easy to obtain
2. inexpensive to produce
3. environmental stability
4. aersol distribution
5. delayed recognition/response
6. perpetrators escape easily
7. susceptible populations
8. catastrophic public health cosequences
- mass casualties overwhelm medical systems
- high morbiditidy, mortality
- contagious

Front 372

biological agents of highest concern

Back 372

1. B. anthracis - only one thats been used
2. Y. pestis
3. F. tularensis
4. Botulinum toxin
5. Variola major (sml pox)
6. filoviruses and arenaviruses (viral hemorrhagic fevers)


b/c
- cause dx via aerosol
- organisms fairly stable in aerrosol
- susceptible civilian populations
- high morbidity and mortality
- some w/person-to-person transmission (smallpox, plague, VHF)
- difficult to diagnose and/or treat
- previous development for biological warfare

Front 373

3 categories of bioterrorist agents

Back 373

category A
- easily transmitted
- easily disseminated
- high mortality rate
- potential for major public heath impact
- req special action for public health preparedness
- bacterial agents = B. antrhacis, Y. pestis, F. tularensis

Category B
- moderate morbidity
- low mortality
- req specific non-standard diagnostic capacity
-moderately easy to distribute
-req enhanced dx surveillance
- bacterial agents = Brucellosis - brucella species, Q fever - Coxiella burnetii, Pstittacosis - chlamydia psittaci, Glanders - burkholderia mallei, Meliodiosis - burkholderia pseudomallei, typhus fever - rickettsia prowazekii
- water threats - cholera - vibrio cholerae, cyrptosporosis - cyrptosporidium parvum (PROTOZOA)
- food safety threats =
1. e.coli O157:H7
2. salmonella serotype typhimurium
3. salmonella serotype enteritidis
4. shigella sonnei
5. shigella flexneri, dysenteriae type 1
6. salmonella typhi
7. vibrio cholerae

Category C
- nnewly discovered dx
- easily obtained
- easy to make and distribute
- potential for high morbidity and mortality

Front 374

Types of bioterrorist events

Back 374

announced = overt
- straight forward victims aware they are being attaccked
- immediate response and results in early tx
- antrhax letters
- device - aerosol bomb, heating - air conditioning systems release


unannounced = covert
- victims not aware
- results in a delay of tx
- presentn to local health care providers w/sx of dx which are not endemic may have atypcial clincial presentation or an atypcial resistance pattern
- physcian may see acute cases in previously healthy populations, increases in fever presentations or sudden increases in resp or
gastrointestinal complaints
- food/water contamination
- aerosol release
- surface contamination
- zoonotic attack

Front 375

delivery system

Back 375

air- aerosol most effective dissemination method
- droplet size less than <10microm - 1-5 microm optimal

food
water
skin mucus membranes

Front 376

step 1 in preparing for a bioterrorism

Back 376

recognition of biological attack
-enviro detection not feasible
- onset of sx is delayed - incubation periods range from days to d=weeks
- sx may be nonspecific - initial presentation mimics flu
- sx may be acute - incapacitation, paralysis, coma, death

Maintain a high level of suspicion in a number of clinical situations
1. rapidly increasing dx incidence in norm healthy population - w/in hours or days
2. epidemic curve that rises and falls during a short period of time
3. unusal rise in number of ppl seeking care, esp w/fever, resp or gastrointestinal complaints
4. endemic dx rapidly emerging at an uncharacteristic time or in an unusual pattern (ex- dx usually spread by fleas in ppl who have no evidence of flea bites or no recent history of being near animals)

5. lower attack rates among ppl who have been indores compared w/ppl outdoors - esp in areas w/filtered air or closed ventilation systems

6. clusters of pts arriving from a single locale

7. large number of rapidly fatal cases
8. pt presenting w/dx that is relatively uncommon and has bioterrorism potenital - pulmonary antrhax, plague, small pox

9. concurrent reports of increased animal deaths

10 unusual age distribution

11. atypical dx presentation

Front 377

step 2 in preparing for bioterrorism

Back 377

develop and use epidemological tools

1. presence or lack of appropriate exposure history
2. travel to location that has high-consequence dx transmission
3. pathogens w/unusual antimicrobial resistance
4. routine surveillance and dx reporting mechanism

Front 378

food bioterrorism or natural event?

Back 378

being ablte to detect difference is difficult
farm to table process involves mi;lions of ppl who handle a variety of foods every day

everything we eat is reg by FDA except meat, poultry, and some egg products are reg by US dept of agriculture

Front 379

american academy of family physician suggestions

Back 379

1. Know how to contact local and state health departments.
2. Maintain contacts with local health officials.
3. Maintain reference materials on the diagnosis and treatment of agents of bioterrorism.
4. Develop a bioterrorism response plan for your office. Be prepared to use infection control practices.
5. Know the requirements for laboratory support.
6. Be aware of proper post-exposure management for patients and health care staff.
7. Develop skills in and resources for counseling patients to minimize the psychological consequences.

Front 380

family Mycoplasmatacea

Back 380

class - mollicutes - soft skin

2 genera that infect humans
1. Mycoplasma
species: M. pneumoniae, M. hominis, M. genitalium
2. Ureaplasma
species - U. urealyticum

Front 381

M. pneumoniae

Back 381

upper resp tract dx
tracheobroncitis - accompanied by acute pharyngitis 70=80% of infections
atypical pneumoia = walking pneumonia= 10% infections - mild dx but long duration
chronic asthma
pharyngitis

most common in school age children and youg adutlts bt everyone is susceptible - adutlts might be partially immune due to previous exposure
- not reportable dx
- 2 mil cases US anually - 100,000 hospitalizations
- no seasonal variation
- epidemics occurevery 4-8 years
- dx spread by close contact via aerosolized droplets

incubation - 2-3 weeks
- fever, headahe and malaise
- persistent dry nonproductive caugh
- patchy bronchopneumonai may precede symptoms
- acute pharyngitis may be present
- organisms persist - slow resolution - rarely fatla
- mm pain and GI sx usually not present

immunity - complement activation - alternative pathway
- phagocytic cells
- inflammatory cells migrate to site and release cytokines such as TNF - alpha, IL-1 and IL-6
- Ab IgA imp

l

Front 382

M. hominis

Back 382

pyelonephritis
systemic infections in immunocompromised
postpartum fever
PID

Front 383

M. genitalium

Back 383

nongonococcal urethritis
PID

Front 384

U. urealyticum

Back 384

nongonococcal urethritis
pyelonephritis
spontaneous abortion/premature birth

Front 385

Morphology and physiology of mycoplasmas

Back 385

smallest free living bacteria 0.2-0.8 microm - - mistaken for viruses

small genome size 800kbp - require complex media for growth

facultative anaerobes - except M.pneumoniae strict aerobe

lack cell wall, membrane contains sterols - resistant to penicillins, cephalosporins, vancomycin

grow slowly by binary fission = doubling time can be 16 hr for M genitalium, 6 hr for M. pneumoniae, 1 hr for ureaplasma

fried egg colonies
- except for M. pneumoniae colonies have granular appearance - mulberry shapped - may take up to 3 weeks to develop usually very small

ureaplasma species w/granular, urease-positive colonies abt 15-50 microm in diameter - extremely small aka T-strains - tiny strains

multiple shapes including round, pear shaped eveen filamentous

require complex media to grow - includign sterols - growth for membrane species

major antigenic determinants are glycolipids and proteins - some cross link w/human tis

Front 386

differentiate btw species of mycoplasms

Back 386

differentiated by their ability to metabolize - growth requirements

M. pneumoniae - glucose
M. hominis - arginine
U. urealyticum - urea (needs buffered media due to growth inhibition in alkaline media)

M. genitalium - difficult to culture

Front 387

Pathogenesis of mycoplasms

Back 387

adherence
P1 pili - M. pneumoniae - binds to sialic acid residues on host epithelial cell
- mvmt of cilia ceases - ciliostassis
- clearance mech stops resulting in cough
- M. genitalium uses MgPa adhesions to attach to epithelial cells

toxic metabolic products
- H2O2
- inhibition of catalase

immunopathogenesis
- activate macrophages
- M. pneumoniae stimulate B and T lymphocytes and induce formation of AutoAb reacting host tissues and teh I ag on RBC ( cold agglutins) - superag

- ureplasmas produce IgA protease

- mostly thought of as extracellular pathogens but now appreciated that M.pneumonaie and M. genitalium can be intracellular - affording protection from IS and abx

Front 388

Labatory diagnosis of M. pneumoniae

Back 388

microscopy - difficult to stain b/c absence of cell wall - eliminate other organims

culture - definitive diagnosis
- sputum usualy scant - or throat washings
- special transport medium needed - must suspect M.pneumoniae
= may take 2-3 weeks or longer, 6 hr doubling time w/glucose and pH indicator included
- incubation w/antisera to look for inhibition = not a typical test

serology
- complement fixation - 4-6 weeks, 4fold rise in titer (req collection of 2 samples 3-4 weeks apart)
- relatively insensitive - dont' peak until 4-6 weeks after infection
= ab may persist up to 1 year = sustained high titer = doesn't equal current infection

- cold agglutins - 1/3 - 2/3 pt, I Ag, appear first, not specific or insensitvie - Ab to agglutinate erythrocytes at 4deg C but not at 37 deg C - Not specific

Molecular diagnosis
- PCR based tests have been developed and tehse are expected to be diagnostic test of choice in the future - targets for amplification include 16 S rRNA, P1 adhesion gene, MgPa adhesion gene - relatively fast doesn't depend on culture or viable organism - should have good senesitivity and be specific for these slow growing and difficult to culture organisms

- ELISA - commercially available

Front 389

tx and prevention of M. pneumoniae

Back 389

tetracycline/doxycycline in adults or erythromycin in kids - newer fluoroquinolones in adults
- resistant to cell wall synthesis inhibitors

prevention- avoid closs contact
isolation is not practical due to length of illness
no vaccine although attempted

Front 390

family- chlamydiaceae

Back 390

genus chlamydia
- C. trachomatis - urogenital infections, trachoma, conjunctivitis, pneumonia, and lymphogranuloma venereum

genus - chlamydophila
0 C. psittaci - pneumonia (psittacosis)
- C. pneumoniae - pronchitis, sinusitis, and possibly tatheroslerosis

small obligate intracelluar parasites
- contain DNA RNA and ribosomes - genome size 1-1.24 Mbp

inner and outter membrane - like gram negative bacteria

LPS but no PG - cell wall not well characterized
- LPS has weak endotoxin activity
-Energy parasites - can't make ATP

Front 391

elementary bodies

Back 391

small 0.3-0.4 microm infectious form of chlamydiaceae

posses a rigid outer membrane - resistant to harsh environmental conditions
- Major outer membrane protein unique to species and variations in serovars
- disulfide linked proteins (OMP2) hihgly ocnserved - gives stability

bind to receptors on host cells and initiate infectino
- infect columnar epithelial cells but some also infect macrophages

non replicating non metabollically active

Front 392

reticulate bodies

Back 392

larger (o.8-1 microm) non-infectious intracellular fomr of chlamydis

metabolically active replicating form

possess fragile membrane lacking extensive disulfide bonds -characteristic of EB

Front 393

Developmental cycle of chlamydiaceae

Back 393

1. EB binds to receptor on susceptible cells
2.internalized by endocytosis/phagocytosis
3, inside the EBB reorganizce and become RB
4. chlamydia inhibit the fusion of the endosome w/lysosomes and resist intracellular killing
5. entire life occurs w/in endosome - replicating by binary fision and reorganization into EB
6. Cells and inclusions lyse w/ C.psittaci
- or inclusion is extruded by reverse endocytosis C. trachomatis and C. pneumoniae

Front 394

chlamydia trachomatis

Back 394

tracoma
inclusion conjunctivitis
infant pneumonia
ocular lymphogranuloma venereum
urogenital infections
reactive arthritis - Reiter's syndrome
lymphogranuloma venereum

biovars - trachoma, LGV< mouse pneumonitis
Serovars - serological varients - different MOMP A-L
- A, B, Ba, C = trachoma (tracoma biovar)
- D-K = Urogenitial tract dx (trachoma biovar)
- L1, L2, L2a, L2b, L3 - lymphogranuloma venerum (LGV biovar)

Infects nonciliated columnar, cuboidal and transitional epitehlium (macrophages in LGV)
- down reg Class I MHC
- infiltration of PMNs and lymphocytes
- lympohoid follicle formation
- fibrosis
- dx results from destruction of cells and host immune response
- no lasting immunity - reinfection results in inflammatory response and tissue damage

Front 395

Ocular infections due to C. trachomatis

Back 395

biovar trachoma
- world wide
-poverty and overcrowding
- endemic in Africa, Middle east, india, SE asia
- US _ american indians
-infection of kids
- transmission = droplets hands, contaminated clothing, flies, during birth
- damage to eyes not immediate

Front 396

genital tract infections from C. trachomatis

Back 396

biovar - trachoma - Most common STD in US
- est 2.8 mil cases/year in US - mostly underreported - 50 new cases/year world wide

-Biovar LGV
- humans only natural host
-prevalent in africa, asia and SA
- sporadiic in USA 300-500 cases/ year
- male homos

Front 397

Trachoma

Back 397

chornic or repeated syndrome
C. trachomatis A-C serovire/ biovar trachoma
- follicle formation on conjunctiva
- scaring of conjunctiva
- eyelids turn in and abrade cornea - ulceration, scarring, BV formation
- flow of tears impeded - secondary infections

Front 398

inclusion conjunctivitis

Back 398

C. trachomatis biovar - tracjhoma
assoc w/ genital chlamydia serovars D-K
- mucopurulent discharge
-corneal infiltrates, vascularization and scaring
neonates infection results from infected birth canal
- apparent 5-12 days after birth
- ear infection and rhinitis often accompany ocular dx

Front 399

infant pneumonia

Back 399

C. trachomatis biovar - trachoma
- assoc w/genital chlamydia serovars D-K
- infection arises from cont birth cannal
-wheezing cough and pneumonia but no fever
-often preceded by conjunctivitis

Front 400

ocular lymphogranuloma venereum

Back 400

infection w/LGV serovars L1-L3/ LGV biovar of C. trachomatis

oculoglandular conjunctivitis and assoc lymphadenopathy - infect macrophages

Front 401

urogenital infections from C.trachomatis

Back 401

biovar trachoma

females:
-asymptomatic 80%
-cervicitis, urethritis, and salpingitis
- postpartum fevere
- increased rate of premature delivery and ectopic pregnancy

Males -
- symptomatic 75%
- urethritis, dysurina and pyuria
- cause of nongonococcal uretrhitis 35-50%
- common cause of post gonococcal urethritis - might have both bacteria
sx appear 3 weeks after infection and abate by 12 weeks

Front 402

reactive arthritis

Back 402

aka reiter syndrome
- due to C. trachomatis
- conjunctiviits, polyarthritis and or genital.GI inflamation

assoc w/HLA B-27 (MHC class surface ag assoc w/certain autoimmune dx
50-65% C. trachomatis infection
80% have Ab to C. trachomatis

Front 403

lymphogranuloma venerum

Back 403

c. trachomatis biovar LGV
1st stage
- small painless vesicular rlresion at site of infection
- fever headache myalagia

2nd stage
- inflammation of draining LN
- fever, headache and myalgia
- buboes - rupture and drain
- proctitis
- genital ulcers or elephantiasis

Front 404

C. trachomatis diagnosis

Back 404

- iodine staining inclusions - glycogen
- need tissue to see not just puss
-not sensitive

culture - iodine staining inclusions
- infect cell lines
- most specific

iodine staining glycogen specific for C. trachomatis b/c other species of chlamydia do not contain glycogen and stain w/iodine

antigen detection 0 ELISA or IF
-group specific LPS
- stain specific outer membrane protiens to id serovar
- serology can't distinguish btw current or past infections
- detection of high titer IgM ab can be helpful to diagnose current condition

Nucleic acid proges
- several kits available
-sensitive and specific

Front 405

treatment and prevention of C. trachomatis

Back 405

tetracycline
macrolides
sulfonamides
vaccines- of little value since no immunity w/infection
-tx coupled w/improved sanitation
- safe sex practices
tx of pt and sexual partners

Front 406

Chlamydophila psittaci

Back 406

Psittacosis - parrot fever
- ornithsis - since all birds carry it

inhalation of organisms in bird dropping - person-to person -transmission is rare
-hematogenous spread to spleen and liver - local necrosis of tissue
- hematogenous spread to lungs and other organs
lymphocytic inflammatory response
- edema infiltration of macrophages, necrosis and occasionally hemorrhage
- mucuss plugs may develop in alveoli
- cyanosis and anoxia
- atypical pneumonia

50-100 cases a year in USA
- asymptomatic or symptomatic in birds - tissue, feces, feather
- primarily occupational dx - vets, poultry workers, zoo keepers, pet shop workers

incubation period - 1-2 weeks
-fever, chills, headache, noproductive cough, mild pneumonitis
recovery 5-6 weeks = uncomplicated

complicated = also sx- mental confusion, cyanosis, jaundice
- prolonged recovery -7-8 weeks

diagnosis -- serology - complement fixation test
- fourfold rise in titer
- rewuires paired samples

tx - tetracycline or erythromycin - sulfnamides do not work
- quarantine of imported birds
- control of bird infection - abx supplementation of food - may lead to resistant strains


asymptomatic infections are common
complicated cases - convulstions coma and death or carditis, hepatomegaly, splenomegaly

Front 407

chlamydophila pneumoniae

Back 407

TWAR agent - twp isolates ended up being identical Taiwan TW-183 and acute resp isolate AR-39
atypical pneumonia = walking pneumonia
- also causes pharyngitis, bronchitis, sinusitis,
atherosclerosis

transmission - person to person spread by respiratory droplets

sx do not differ from viruses and mycoplasma pneumoniae

common infection
primarily in adults
most infections are asymptomatic
assoc w/crowded condtitions

tentative assoc w/atherosclerosis - org in aterial lesions
- antibodies to C> pneumoniae

mild or asymptomatic dx => pharyngitis, bronchitis, persistent cough and malaise - usually only a single lobe

diagnosis - serology - fourfold rise in titer in paired samples

tx- tetracycline or erythromycin
- difficult to prevent - no vaccine

Front 408

rickettsia
orientia
ehrlichia
anaplasma
coxiella

biology

Back 408

small obligate intracellular parasites - used to be considered viruses

- separate unreleated genera
-gram neg bacteria but stain poorly w/gram stain - coccobacilli - stain w/giemsa

- energy parasites - but nt obligate - have capacity to make ATP
- transport system for ATP is very efficient
- reservoirs - animals, insects, humans

- arthropod vectors except coxiella

origiinally thought to be part of same fam but now considered to be distinct unrelated bacteria

Front 409

replication of rickettsia and orientia

Back 409

infect endothelial cells in sml blood vessels - induced phagocytosis
- lysis of phagosome and entry into cytoplasm
- produce phospholipase
- replication and release via cell lysis = R. prowazekii or through local projections (filopodia = R. rickettsii- F actin in host assoc w/ R. rickettsii and actin help push bacteria through filopodia
O. tsutsugamushi exits by budding through the cell membrane and remains enveloped in host cell membrane until it infects other cells

Front 410

pathogenesis and immunity of rickettsia and orientia

Back 410

no known toxins or immunopathology
destruction of endothelial cells in multiple organs
- leakage of blood into tissues = rash
- organ and tissue damage

- humoral and cell mediated immunity imp for recovery
- Ab -opsonized bacteria re killed - CMI develops

Front 411

Rickettsia rickettsii

Back 411

Rocky mountain spotted fever
- detected by fluorescent Ab staining from punch biopsy - also by PCR based tests
= Weil - Felix test - agglutination of O ag of some rickettsial specis- no longer recommended
- serology - indirect fluorescent Ab test for Ab - latex agglutination test for Ab
Vector = hard tick= lxodid tick via saliva - prolonged exposure to tick is nec - bacteria ini gut and blood meal stimulates bacteria to divide - goes to salivary glands then to human

reservoirs - ticks - transovarian passage to eggs and rodents - humans accidently infected
- most common rickettsial infection in US - 2000 cases annual - south central US - high in NC and SC
not as frequent in rocky mtn states

most common from april-september
incubation period 2-12 days
- abrupt onset fever, chills, headache and myalgia
rash appears 2-3 days later in 90% of pts
- begins on hands and feetand spreads to trunk regardless of biine location (centripetal spread)
- palms and soles commonly have rash
- maculopapular but can become petichial or hemorrhagic

complications from widespread vasculitis
- GI , resp, seizures, coma, renal failure
- most common when rsash doesn't appear
- mortality in untx cases = 20%

tx, prevention and control
- tetracycliine (doxycycline) and chlorampheicol - relapse and side effects - prompt tx reduces morbidity and mortality
-no vaccine
-prevention of tick bites and prompt removal of ticks
- cant control reservoir

Front 412

Rickettsia akari

Back 412

Rickettsialpox
- sporadic infectionm in USA - urban areas
- vecto house mite
- reservoir - mite (transovarian transmission) and mice
- humans accidently infected

phase I - 1 week incubation perioid
- papule at bite site
- eschar formation

phase II - 1-3 weeks latere
- sudden onset of fever, chills headache myalgia
-generalized rash - papulovevsicular, crusts (rash resembles chickenpox)
- mild dx - fatalities are rare
- pox heal w/in 2-3 weeks w/no scaring

labatory diagnosis - not available except in reference labs

tx - tetracycline (doxycycline)
- contorl of mouse population

Front 413

Rickettsia prowazekii

Back 413

epidemic typhus
brill zinsser dx

assoc w/unsanitary conditions
- war, famine - aka camp fever
- vector human body louse - bacteria found in feces and when bite scratched bacteria infect

reservoir - primarily humans - endemic form
- no transovarian transmission in louse - bacteria kills louse

sporadic dx in southeeaster usa
- flying squirrels = reservoir
- vector - squirrel ectoparasites - fleas/ticks

incubation abt 1 week
- maculopapular rash progressing to petechial or hemorrhagic
- first on trunk and spreads to extremities - centrifugal spread
- complications - myocardiits, stupor, delirium

recoverty takes months - debilitating
mortality rate high 60-79% but may be because situation - famine

Bill-zinsser dx - recrudescent epidemic typhus - commonly seen in those exposed previously -maybe decades later
-similiar to epidemic typhus but milder - rash rare - high index of suspician needed for diagnosis

Weil-felix Ab (cross reactivity w/antigens on Proteus) not recommended
- isolation possible but dangerous
- serology - indirect flourescent Ab and latex agglutination tests
epidemic typhus - IgM followed by IgG abs
- Bill zinsser - IgG

tx- tetracycline (doxycycline and chloramphenicol
-louse control measures
- vaccine available for high risk populations

Front 414

Rickettsia typhi

Back 414

murine or endemic typhus

occurs world wide
vector- rat flea
bacteria in feces
reservoir - rats
-no transovarian transmission
normalcycle rat- flea- rat
humans accidently infected

incubation period 1-2 weeks
- sudden onset of fever, chill,s headache and myalgia
- rash in most cases
-b egins on trunk and spreads to extremities - centrifugal spread
mild dx=- resolves if untreated

serology - indirect fluorescent Ab test - not done in routine lab

tx - tetracycline (doxycyclien
-control rodent reservoir
- no vaccine

Front 415

Orientsia Tsutsugamushi

Back 415

scrub typhus
scrub - assoc w/terrain w/scrub vegatation

vector - chiggers - mite larva
- reservoir chiggers and rats
- transovarian transmission
- mornal cycle - rat-mite-rat
humans accidently infected

incubation 1-3 weeks
- sudden onsegt of fever chills headache and myalgia
maculopapular rash begins on trunk and spreads to extremities -
mortality rates 1-15%
lab diagnosis serology

tx- tetracycline (doxycycline)
no vaccine
- measure to avoid exposure to chiggers

Front 416

Rickettsia akari

Back 416

Rickettsialpox
- sporadic infectionm in USA - urban areas
- vecto house mite
- reservoir - mite (transovarian transmission) and mice
- humans accidently infected

phase I - 1 week incubation perioid
- papule at bite site
- eschar formation

phase II - 1-3 weeks latere
- sudden onset of fever, chills headache myalgia
-generalized rash - papulovevsicular, crusts (rash resembles chickenpox)
- mild dx - fatalities are rare
- pox heal w/in 2-3 weeks w/no scaring

labatory diagnosis - not available except in reference labs

tx - tetracycline (doxycycline)
- contorl of mouse population

Front 417

Rickettsia prowazekii

Back 417

epidemic typhus
brill zinsser dx

assoc w/unsanitary conditions
- war, famine - aka camp fever
- vector human body louse - bacteria found in feces and when bite scratched bacteria infect

reservoir - primarily humans - endemic form
- no transovarian transmission in louse - bacteria kills louse

sporadic dx in southeeaster usa
- flying squirrels = reservoir
- vector - squirrel ectoparasites - fleas/ticks

incubation abt 1 week
- maculopapular rash progressing to petechial or hemorrhagic
- first on trunk and spreads to extremities - centrifugal spread
- complications - myocardiits, stupor, delirium

recoverty takes months - debilitating
mortality rate high 60-79% but may be because situation - famine

Bill-zinsser dx - recrudescent epidemic typhus - commonly seen in those exposed previously -maybe decades later
-similiar to epidemic typhus but milder - rash rare - high index of suspician needed for diagnosis

Weil-felix Ab (cross reactivity w/antigens on Proteus) not recommended
- isolation possible but dangerous
- serology - indirect flourescent Ab and latex agglutination tests
epidemic typhus - IgM followed by IgG abs
- Bill zinsser - IgG

tx- tetracycline (doxycycline and chloramphenicol
-louse control measures
- vaccine available for high risk populations

Front 418

Rickettsia typhi

Back 418

murine or endemic typhus

occurs world wide
vector- rat flea
bacteria in feces
reservoir - rats
-no transovarian transmission
normalcycle rat- flea- rat
humans accidently infected

incubation period 1-2 weeks
- sudden onset of fever, chill,s headache and myalgia
- rash in most cases
-b egins on trunk and spreads to extremities - centrifugal spread
mild dx=- resolves if untreated

serology - indirect fluorescent Ab test - not done in routine lab

tx - tetracycline (doxycyclien
-control rodent reservoir
- no vaccine

Front 419

Orientsia Tsutsugamushi

Back 419

scrub typhus
scrub - assoc w/terrain w/scrub vegatation

vector - chiggers - mite larva
- reservoir chiggers and rats
- transovarian transmission
- mornal cycle - rat-mite-rat
humans accidently infected

incubation 1-3 weeks
- sudden onsegt of fever chills headache and myalgia
maculopapular rash begins on trunk and spreads to extremities -
mortality rates 1-15%
lab diagnosis serology

tx- tetracycline (doxycycline)
no vaccine
- measure to avoid exposure to chiggers

Front 420

ehrlichia and anaplasma replication

Back 420

infection of leukocytes - phagocytosis
-inhibition of phagosomelysosome fusion
- growth w/in phagosome- morula
lysis of cell

Front 421

Ehrlichia chaffeensis

Back 421

human monocytic ehrilchiosis

vector - tick
suden onset of fever chills headache and myalgia
- no rash in most pts 80%
leukopenia - thrombocytopenia and elevated serum transaminase
mortality rate low <5%

lab diagnosis - microscopic observation of morula in blood smears rare
- culture possible but rare
- serology is most common - DNA probes are available

tx, prevention and control
- doxy avoid ticks

Front 422

Ehrlicha ewigii
Anaplasma phagocytophilum

Back 422

human granulocytic ehrilchiosis and anaplasmosis

vector - tick

sudden onset of fever, shills, headache and myalgia
- NO rash
leukopenia, thrombocytopenia elevated serum transaminases
hospitalization common but mortality rates low <1%

lab - micro observation of morula in blood smears rare
- culture possible but rarely done
- serology most common
- DNA probes available

tx = doxy but rifamin can be used w/pts w/intolerance of doxy
- avoid ticks

Front 423

coxiella burnetii

Back 423

Qfever
id by fluorescent Ab stain

pathogenesis and immunity
- inhalation of airborn particles (infectious dose is very low; ticks are the primary vector in animals)
- multiplication in lungs and dissemination to other organs
- multiplication in lungs and dissemination to other organs
-pneumonia and granulomatous hepatitis isn severe cases
-in chronic dx immune complexes play a role in pathogenesis
-cell mediated immunity imp in recovery

phase (antigenic variation )inLPS ag exxpressed
- acute dx = Ab to phase II ag
- can be mild or asymptomatic- fever, chills, headache and myalgia, resp sx mild, hepato/spleno-megally, granulomas in liver

- chronic dx = Ab to both phase I and phase II
- typic presents as endocarditis on a damaged heart valve - poor prognosis

Stable spore like - small cell varients
- infects many animals including sheep, goats, cattle nad cats

- highg titers in placentas of infected animals

-persists in soil
-found in milk of infected animals
-no arthropod fvector
- dx of ranchers, vets and abettoir workers

lab diagnosis - serology - acute -Ab to phase II ag and chronic - Ab to both phase II and phase I

tx - acute - tetracycline
chronic - combo

vaccine available only used in austrailia

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replication of coxiella burnetti

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obligate intracellular pathogen - gram neg cell wall

infects macrophages

survival in phagolysosome

replication

lysis of cell

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bartonella

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small gram neg aerobic bacilli
difficult to culture

infect animals but do not cause dx in animals

insects are thought to be the vectors in human dx

some species infect erythrocytes and others attach to cells

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bartonella quintana

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trench fever - WWI trenches
= shin-bone fever
- 5 day fever reoccurs every 5 days

assoc w/ war famine, outbreaks among homeless
vector- body louse - organism found in feces
-reservoir - humans - no transovarian transmission
cycle - human-louse-human

infection may be asymptomatic or severe
suddene onset of fever, chills headache and myalgia
severe pain in the tibia
sx may appear at 5 day intervals
maculopapular rash may or may not develop on the trunk
- mortality rates very low but recovery can be lengthy

diagnosis - serology and PCR reference laboratories

tx- various abx - erythromycin or doxy
- control body louse

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bartonella henselae

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cat- scratch dx

acquired from cat bite or scratch and possibly from cat fleas - benign dx
-chronic regional lymphadenopathy

diagnosis - serology

tx - controversial since benign
if tx w/abx then azithromycin used