Block B Mip

Front 1

nitrous acid

Back 1

mutagen that yields point mutations

Front 2

5-bromo-2-deoxyuricil

Back 2

mutagen that yields point mutations

Front 3

Antibiotic

Back 3

against life

Front 4

antimicrobials are NOT

Back 4

1. antipyretics - reduce fever
2. antihistamines
3. Decongestants

Front 5

the perfect antimicrobial

Back 5

1. kills the offending microbe
2. doesn't kill all the microbes
3. doesn't kill the patient

Front 6

Resistance to Quinolone (antibiotic)

Back 6

increased in Pseudomonas aeroginosa and Gram Negative Rods

Front 7

Appropriate use of Antibiotics

Back 7

1. make sure you have a bacterial infection
2. evidence that the treatment makes a difference
3. Narrowness of spectrum
4. Appropriate Drug Characteristics
5. Appropriate Length of Treatment

Front 8

Perfect Antimicrobial

Back 8

1. Kills the offending microbe by attacking vital components/processes
- cell wall
- protein synthesis
- DNA replication
- special environments necessary for growth

2. Doesn't kill other microbes

3. Doesn't kill the host

Front 9

Antibacterial Targets

Back 9

1. the cell wall
2. making the cell wall
3. cell membrane
4. protein synthesis
5. DNA/RNA synthesis

Front 10

Antibacterial Targets—The Cell Wall

Back 10

1. cell walls are made of peptidoglycan
2. Antibioticss that act on cell wall synthesis can be classified into 2 groups
- Beta- lactams
-Glycopeptides

Front 11

β-lactams

Back 11

a. Penicillins
b. Cephalosporins
c. Carbepenems
d. Monobactams

Front 12

Glycopeptides

Back 12

a. Vancomycin
b. Ramoplanin*
c. Dalbavancin*
d. Oritavancin*

Hint 12

Dr. Vo

Front 13

Antibacterial Targets—Making of the Cell Wall

Back 13

1. Bacitracin (used topically),
2. Fosfomycin, and
3. D-cycloserine (used in TB infections)

Front 14

Antibacterial Targets—Cell Membrane

Back 14

1. Daptomycin (newly detailed drug that is effective against gram positive organisms)

2. Polymyxins (binds to gram negative membranes)

Front 15

Antibacterial Targets—Protein Synthesis

Back 15

1. Aminoglycosides
2. Oxazolidinones
3. Tetracycline/Glycycline
4.Chloramphenicol
5.Macrolide/Azalide/Ketolide
6. Lincosamide
7. Streptogramin

Front 16

Aminoglycosides

Back 16

a. Streptomycin—important in treating TB infections
b. Gentamycin—most common one used in hospitals
c. Tobramycin
d. Amikacin

Hint 16

Sgt. A

Front 17

Oxazolidinones

Back 17

Linezolid- Zyvox is the form detailed on us

Front 18

Tetracycline/Glycycline

Back 18

a. Tetracycline
b. Doxycycline
c. Minocycline
d. Tigecycline

Hint 18

TDTM

Front 19

Macrolide/Azalide/Ketolide

Back 19

a. Erythromycin
b. Clarithromycin
c. Azithromycin (i.e. Z-pak)
d. Telithromycin

Hint 19

CATE

Front 20

Lincosamide

Back 20

Clindamycin

Front 21

Streptogramin

Back 21

Quinopristin-Dalpopristin

Front 22

Quinolones

Back 22

the suffix floxacin means a quinolone

1. Ciprofloxacin
2. Leyofloxacin- very common
3. Gatifloxacin- kills people so not used
4. Moxifloxacin- massively detailed
5. Grepafloxacin- kills people so not used
6. Yada yada yada floxacin

Front 23

Folate antagonists

Back 23

cannot make DNA
Tremethoprim-sulfamethexozole

Front 24

Nitroimidazol

Back 24

destroys DNA via an oxidative process

Metronidazole

Front 25

Rifamycin

Back 25

targets RNA

Rifampin—important drug for TB

Front 26

Beta- lactams
(how they function - ez only)

Back 26

inhibit transpeptidase - the enzyme involved in cross-linking

Front 27

Glycopeptides
(function)

Back 27

inhibit both transpeptidase and transglycosidase

Front 28

Beta - Lactams
(How it works)

Back 28

1. irreversibly binds the transpeptidase enzyme and does not allow cross-linking to occur

2. bond between the two alanines is formed by transpeptidase
- this is similar to the bond found in the beta-lactam ring that opens up and binds to the transpeptidase --> irreversibly inactivating it

Front 29

Transpeptidase
(another name)

Back 29

1. also termed Penicillin Binding Protein

Front 30

Beta - Lactams
(structure and classes)

Back 30

1. a molecule with a 4 membered ring

2. various classes of β-lactams
a. Monobactam
b. Penicillin- five membered ring attached.
c. Cephalosporin/Cephamycin- six membered ring
d. Clavulanic
e. Thienamycin
f. Carbapenim

Front 31

Two parts of Beta-lactam antibiotics

Back 31

1. Usually a five-carbon ring - all the classes have a house except Monobactam.

2. Where the mechanism of action takes place (the β-lactam bond between the N and Carbonyl group is found in the garage)

Front 32

Clavulanic acid

Back 32

a very poor β-lactam. It does, however, bind certain transpeptidases very well

Front 33

Gram-positive resistance to Beta-lactams

Back 33

1. produce beta-lactamase
2. alter the structure of transpeptidases/PBP
3. increase the amount of Transpeptidase/PBP

Front 34

Treatment with B-lactamase production

Back 34

1. treat with antibiotic that is not sensitive to beta-lactamase

2. combine treatment with beta-lactamase inhibitor

Front 35

Treatment with altered transpeptidase/PBP target

Back 35

1. increase beta-lactam dose in order to force the issue

2. choose another drug that does not bind transpeptidases/PBPs

Front 36

Gram- negative resistance to B-Lactams

Back 36

1. produce B-lactamase
2. Decrease porin concentration in outer membrane
- B-lactams must first penetrate the outer membrane via porins

3. express efflux pumps on outer membrane

4. alter the structure of transpeptidase/PBP

Front 37

Beta-lactamase

Back 37

1. structurally mimics transpeptidases/PBPs

2. β-lactamase therefore sequesters β-lactams and allows the transpeptidases/PBPs to carry out their cross-linking functions in cell wall synthesis

3. In most cases, the affinity between the β-lactam and β-lactamase is greater than between β-lactam and transpeptidase/PBP

4. β-lactamase is very efficient – once it binds to and inactivates one β-lactam, it will release and bind/inactivate another β-lactam

Front 38

β-lactamase inhibitors

Back 38

1. Clavulanic acid
2. Sulbactam
3. and Tazobactam

Front 39

Hemophilus influenzae

Back 39

1. common cause of Otitis Media

Front 40

Piperacillin + Tazobactam (Zocin®)

Back 40

broad spectrum antibiotic very similar to the Carbapenems

carbapenems are structurally similar to β-lactams and are also β-lactamase resistant

Front 41

Membrane efflux bacteria --> must be gram negative

Back 41

pseudomonads

augmentin won't work

Front 42

altered transpeptidases/PBPs Resistant Bacteria

Back 42

Streptococcus pneumoniae

Front 43

Vancomycin

Back 43

1. a glycopeptide

2. hydrogen bonds to the D-alanyl-D-alanine motif of the peptidoglycan pentapeptide chain
-essentially covering up the active site for transpeptidase/PBP and preventing peptidoglycan cross-linking

3. works in the same step of cell wall synthesis as the β-lactams, however instead of binding to the transpeptidase/PBP (as β-lactams do) it binds to the D-alanyl-D-alanine motif of the peptidoglycan (i.e. the target site for transpeptidase/PBP).

4. gram-positive spectrum only

5. slow killing antibiotic

Front 44

Fosfomycin

Back 44

1. is active against the cell wall of bacteria

2. Licensed for single-dose therapy for UTIs

3. Broad spectrum for gram-positive and gram-negative organisms in the urinary tract

4. Possible use in enterohemorrhagic E. coli (EHEC) infections because most other antibiotics make this condition worse.

Front 45

Cycloserine

Back 45

A. Used primarily in multi-drug resistant tuberculosis

B. Must be given in combination with other drugs to prevent development of resistance

Front 46

Bacitracin

Back 46

A. Reduces the numbers of S. auereus carriers (NT Note: 30% of us carry S. aureus in oral and nasal mucous membranes.)

B. Gram-positive spectrum

C. Poorly absorbed from the intestinal tract

D. Typically given as a topical ointment mixed with neomycin and polymyxin for use against mixed bacterial flora on surface lesions

Front 47

Cyclic Lipopeptides

Back 47

A. Active against the cell membrane of organisms

B. Daptomycin and Polymyxin

Front 48

Daptomycin

Back 48

a. Causes cell membrane depolarization

b. Gram-positive spectrum

c. Drawbacks: unable to use for Lung, Urinary tract, or CNS infections

d. Side effects: reversible myopathy
i. Since daptomycin is not specific for bacterial cell membranes only, host cell membranes can also be targeted and subsequently depolarized.
ii. Tissues most dependant on a functional cell membrane polarity are muscle and nerve tissue.

Front 49

Polymyxin

Back 49

a. Binds to lipopolysaccarrhides (major constituent of the outer parts of gram-negative bacteria) and also causes membrane depolarization, which kills the organism.

b. Gram-negative spectrum

c. Side effects similar to daptomycin (myopathies) due to host cell membrane targeting

d. This is a “drug of last resort” due to its toxic nature and broad spectrum.

Front 50

Vancomycin is used for

Back 50

1. against β-lactam-resistant, gram-positive organisms (e.g. Methicillin-resistant S. auereus)

2. for patients with penicillin allergy

3. against intestinal enterocolitis due to C. difficile infection
a. vancomycin is administered orally due to the intestinal nature of this infection (it is not readily absorbed across intestinal membranes)
b. IV administration for systemic infections

Front 51

Resistance to vancomycin

Back 51

1. increasing due to its frequent use against MRSA

2. Organisms can develop an extremely thick cell wall that essentially traps vancomycin molecules outside and away from where the transpeptidase/PBP works

2. The vancomycin-resistant organism can change the amino acid structure of their cell wall (the last D-alanine of the pentapeptide chain changed to a lactate — D-alanyl-D-alanine  D-alanyl-D-lactate), thus preventing vancomycin from binding.
- NO CURRENT METHOD AROUND THIS RESISTANCE
- Many species of Enterococcus (particularly E. faecium) utilize this resistance mechanism
- In many patients with vancomycin-resistant S. Auereus infection, the resistance is due to a co-infection with Enterococcus.

Front 52

Reactions to vancomycin treatment

Back 52

1. Anaphylaxis (red man syndrome)

2. Ototoxicity

3. Nephrotoxicity

4. True allergy

Front 53

Ramoplanin

Back 53

a. Approved for use in Europe
b. Given orally
c. Spectrum: C. difficile
d. Has different target site than vancomycin but still prevents the cross-linking of the peptidoglycan pentapeptides in the cell wall.

Front 54

Dulbavancin/Oritavancin

Back 54

a. Newer drugs still being developed

b. Benefit of this glycopeptide is that it only needs to be given intravenously once a week, whereas vancomycin requires daily IV administrations.

Front 55

80 S ribosome

Back 55

Eukaryotic cells

Front 56

Gram Stain

Back 56

1. Step 1: Crystal violet

2. Step 2: Grams Iodine
- mordant - complexes with crystal violet and fixes dye in cytoplasm

3. Step 3: Decolorizer
- alcohol or acetone

4. Step 4: Safranin Red

Front 57

Staphylococcus aureus

Back 57

1. Gram +
2. looks like clusters of grapes

Front 58

Escherichia coli

Back 58

Gram -

Front 59

Acid Fast Staining organism characteristics

Back 59

1. have a component to their cell wall called mycolic acid, which makes their cell wall impermeable to the primary stain.

Front 60

Steps of Acid Fast Stain

Back 60

1. Primary dye - carolfuchsin red

2. Decolorizing Agent - HCL + alcohol
- can't wash away stain from acid fast organisms

3. Methylene blue - to visualize non acid fast organisms

Front 61

Capsule

Back 61

1. typically composed of high molecular weight polysaccharides
- exception to this is the Bacillus anthracis capsule, which is composed of polypeptides.

2. important virulence factors
- protect against complement
- antiphagocytic

3. poor antigens - polysaccharides in the capsule are T-cell independent (TI-2) antigens
-decreasing the formation of memory B cells and accounting for the susceptibility of infants

4. facilitate the adherence of bacteria to surfaces

Front 62

Klebsiella pneumonia

Back 62

patient starts to cough up rusty sputum

bronchial pneumonia

Front 63

glycocalyx

Back 63

less organized form of a capsule that resembles a polysaccharide film over the surface of bacterial cells

Front 64

S-layer or slime layer

Back 64

even less organized than a glycocalyx and appears as a matrix of fibers on the bacteria external surface.

Front 65

LPS

Back 65

1. in outer membrane of Gram - bacteria

2. made of repeating sugar residues (O-antigenss) attached to core sugars

3. The core sugars are in turn attached to a disaccharide-diphosphate with fatty acid moieties (Lipid A)

Front 66

Porins

Back 66

1. also known as outer membrane proteins (OMPs).

Front 67

Cell wall

Back 67

1. also known as the peptidoglycan layer, or the murein layer

Front 68

Periplasmic space

Back 68

1. found only in Gram-negative bacteria

2. bound by the internal surface of the outer membrane and the external surface of the cytoplasmic membrane.

3. This space contains multiple enzymes, including enzymes that degrade some antibiotics and enzymes for peptidoglycan synthesis.

Front 69

Common pili (fimbriae or type IV pili

Back 69

mediate adhesion/attachment to host eukaryotic cells with specialized tip structures that recognize specific carbohydrates.

Front 70

Sex pili

Back 70

modified to transmit DNA from one bacterial cell to another in a process called conjugation.

Front 71

Pili functions

Back 71

1. mediating adhesion

2. inhibiting phagocytosis

3. highly antigenic

Front 72

Bacillus anthracis toxin

Back 72

encoded in a virulence plasmid

Front 73

Mesosomes

Back 73

1. invaginations of the cytoplasmic membrane that are involved in cytoplasmic septation.

2. where you make the dividsion between daughter cells

Front 74

Endospores
(overview)

Back 74

1. resistant to desiccation, light, heat, many disinfectants, radiation, antibiotics, etc.

2. can be killed by autoclaving

3. endospores can get into tissues and germinate when the environment is favorable

4. DO NOT PICK UP A GRAM STAIN
- will look like a clear zone

Front 75

Medically important spore-forming bacteria

Back 75

1. Bacillus
2. Clostridium

Front 76

Endospore
(structure)

Back 76

1. core which is made up of a copy of genetic material
2. very little water
3. a few enzymes
4. covered by a double-layer of peptidoglycan with dipicolonic acid.
-acid compound binds calcium, creating a calcium shell around the whole endospore.

Front 77

Vibrio

Back 77

1. people with impaired iron metabolism are susceptible to Vibrio infections

2. some bacterial toxins are activated in the presence of iron

Front 78

Metabolic parsimony

Back 78

metabolizing and producing toxins that provide the most energetically efficient benefit to the organism

Front 79

Sterilization

Back 79

1. Autoclaving
2. Dry heat
3. UV or ionizing radiation
4. Gas vapors

Front 80

Autoclaving

Back 80

121 degrees celcius
15 PSI
20 minutes

the only thing it doesn't kill is prions

denaturation process

Front 81

Dry heat

Back 81

160 degrees celcius
2 hours

Front 82

UV or ionizing radiation

Back 82

damages nucleic acids

Front 83

Gas vapors

Back 83

alkylate proteins in DNA to kill all forms of life

Front 84

Disinfection

Back 84

1. reducing the organism burden such that incidence of infection is also reduced

2. Effectiveness affected by: pH, contact time, presence of organic matter, temperature

Front 85

Lysol

Back 85

disinfectant

phenolic compounds that denature proteins

Front 86

bleach

Back 86

disinfectants

chlorox and other chlorine compounds that oxidize sulfhydryl groups

Front 87

Antiseptics

Back 87

1. inhibit or eliminate microbes that are in/on living tissue

2. will kill spores with prolonged contact time

Front 88

Common antispetics

Back 88

1. Ethyl or isopropyl alcohol - denatures proteins

2. Iodophors - denautre proteins
- Povidone iodine

Front 89

PCBs

Back 89

polychlorinated biphenyls - probable human carcinogen

Psduomonas detoxify them for us

Front 90

Aminoglycoside

Back 90

bind to 30S ribisome an dkill by blocking initiation of peptide chain

Front 91

Macrolides

Back 91

bind to 50S ribosomal subuints and prevent peptide chain elongation

Front 92

Rifampin

Back 92

1. an anti TB drug
2. blocks RNA synthesis by interfering with RNA polymerase

Front 93

Peptidoglycan production

Back 93

NAG and NAM made in the cytoplasm and transported across the membrane by a lipid carrier

subunits are polymerized and then crosslinked

Front 94

Vancomycin

Back 94

inhibits the polymerization step of peptidoglycan

Front 95

Bacitracin

Back 95

inhibits lipid carrier recharging for transporting peptidoglycan

Front 96

episome

Back 96

plasmid integrated into the host's chromosomes

Front 97

Cefazolin (IV)
Cephalexin (PO)

Back 97

Spectrum
1. Strep/Staph
2. Enteric GNR

Side Effects
1. Immunologic
2. Seizures

Front 98

Cefuroxime (IV/PO)

Back 98

Spectrum
1. Cefazolin + Haemophilus

Side Effects
Cefazolin +

Front 99

Ceftriaxone IV
Cefotaxime IV
Cefixime PO

Back 99

Spectrum
1. Strep/Staph
2. Enteric GNR
3. CSF OK

Side Effects
1. Biliary effects +
2. Cefazolin

Front 100

Ceftazidime IV
Cefepime IV

Back 100

Spectrum
1. Enteric GNR
2. PSeudomonas
3. CSF OK

Side Effects: Cefazolin +

Front 101

Cefoxitin IV
Cefotetan IV

Back 101

1. Spectrum
Cefazolin +
anaerobes

2. Side effects
Cefazolin +

Front 102

Penicillin G (IV)
Penicillin V (PO)

Back 102

Spectrum:
1. Streptococci (good coverage; examples of use: pharyngitis, cellulitis)
2. Treponema (the agent of syphilis)
3. Oral anaerobes (used by dentists)

Side Effects:
1. Immunologic (can get anaphylaxis-type I hypersensitivity or serum sickness-type III hypersensitivity.
2. Seizures If you give a patient too much Penicillin, it can cross-react with GABA (a neurotransmitter) and cause seizures.

Front 103

Ampicillin (IV)
Amoxicillin (PO)

Back 103

1. Narrow spectrum; used more often than penicillin because it has good bioavailability (levels in the blood can be easily predicted)

Spectrum
1. Pen +
2. Haemophilus (pediatricians deal with this a lot because it is a cause of otitis media)
3. Listeria- can cause meningitis

Side Effects:
1. Pen +
2. Rash :ex. Pt comes in w/ mono and gets sore throat and rash all over the body after ampicillin. It’s due to interaction of the mono with ampicillin.

Front 104

Nafcillin (IV)
Oxacillin (IV)
Dicloxacillin (PO)

Back 104

Very specific for staphylococci. Very good, especially with MRSA. They are resistant to β-lactamase. Because S. aureus produces β-lactamase, these are the preferred Antibiotics to use for S. aureus infections.

Spectrum: Staphylococci

Side Effects
1. Pen+
2. Nephritis

Front 105

Ticarcillin (IV)
Piperacillin (IV)

Back 105

They are sensitive to β-lactamase but are great at killing pseudomonas.

Therefore, they are frequently given in combintation with β-lacatamase inhibitors. Used often due to resistant issues (”hard to kill bugs”)


Spectrum:
1. Amp +
2. Enteric Gram Negative Rods (GNR)
3. Pseudomonas (imp for patients in intensive care)

Side Effects:
Pen+

Front 106

Imipenem (IV)
Meropenem (IV)
Doripenem (IV)

Back 106

1. More often used in people who are dying and have widespread infection

2. spectrum
Streptococci
Staphylococci
Enteric GNR
Acinetobacter
Pseudomonas
Anaerobes
(CSF OK)

3. Side Effects
Immunologic
Seizures

Front 107

Ertapenem (IV)

Back 107

Streptococci
Staphylococci
Enteric GNR
Anaerobes
(CSF OK)

Side effects: Immunologic and seizures

Front 108

Aztreonam (IV)

Back 108

1. Only goes after GNR and pseudomonas

2. spectrum:
Aerobic GNR
Enteric GNR
Psuedomonas
NOT Anaerobes
NOT Gram Pos.
Affects pseudomonas and acinetobacter

3. side effects
immunologic
seizures

4. monobactam

Front 109

prokaryotic ribosome

Back 109

70S consisting of 50S and 30 S subunits

Front 110

30 S subunit

Back 110

binds to mRNA and initiates protein synthesis

Front 111

50 S subunit

Back 111

1. binds tRNA and catalyzes peptide bond formation

2. P and A sites are common locations for antibiotic action

Front 112

P site

Back 112

the donor peptidyl site, where the growing peptide chain is fixed

Front 113

A site

Back 113

the acceptor aminoacyl site, where peptide bond formation occurs.

Front 114

Good sites for anti-ribosomal Abx

Back 114

1. P site
2. A site
3. 50S tunnel - where Manufactured proteins exit during protein synthesis

Front 115

Anti ribosomal Abx methods of action

Back 115

1. inhibit initation
2. inhibit elongation
3. cause mis-reading resulting in the production of non- or poorly- functioning proteins

4. most of the anti-ribosomal Abx bind reversibly to the ribosome, and therefore are susceptible to efflux and other resistance mechanisms

Front 116

Bacteriostatic
(drug examples)

Back 116

1. Macrolide,
2. azalide,
3. and ketolide antibiotics

Front 117

Aminoglycosides
(Mechanism)

Back 117

1. Binds irreversibly to the 30S subunit, which has two functions:
a. Blocks chain elongation resulting in a 90% reduction of protein synthesis
b. Causes misreading of the mRNA resulting in non-functioning proteins

2. Bacteriocidal

3. Spectinomycin is listed as a bacteriostatic aminoglycoside on the Abx Table, but was not discussed in class

Front 118

Amingoglycosides
(Properties)

Back 118

1. contact dependent killers

2. 2. Have a ‘Post-antibiotic effect’: the bacteria is inhibited by the Abx even when levels are diminished

3. Serum levels should be monitored:
a. The peak level in serum determines its effectiveness (i.e. concentration dependent)
b. The trough (i.e. the level preceding the next dose) is important in determining accumulation in the body.
i. Accumulation may cause renal toxicity and failure

Front 119

Aminoglycosides
(spectrum)

Back 119

1. Gram - Rods
2. Not anaerobes - they don't work well in anaerobic conditions
3.Gram + cocci (must be in combination with other Abx- (e.g. beta-lactam Abx or vanco))

Front 120

Streptomycin

Back 120

1. aminoglycoside

2. used to treat Tuberculosis (TB) in the past, and recently again for resistant TB;

3. also used to combat F. tularensis and Y. pestis infections

4. In combination with beta-lactam Abx: for treatment of Enterococcus

5. Not used as much now due to its ototoxicity

Front 121

Gentamycin

Back 121

1. aminoglycoside

2. most commonly used

3. spectrum: Gram -, but not anaerobes

4. one of the two work horses

Front 122

Tobramycin

Back 122

1. aminoglycoside

2. has particular affinity for Pseudomonas

3. typically used for blood stream and UTIs

4. Also used in combination for many organisms including Enterococcus

Front 123

Amikacin

Back 123

a. Used for multidrug resistant Gram – rods (GNR).

b. Can be used in substitution for Streptomycin

c. enzyme modification tends NOT to affect Amikacin - why it's used for Abx resisitant GNRs

Front 124

Aminoglycoside Resistance

Back 124

1. Enzymatic modification
2. Altered ribosomal target
3. Decreased permeability
4. Efflux pumps

Front 125

Aminoglycoside Resistance
(Enzymatic Modification)

Back 125

1. Bacterial enzymes change the Abx to an inactive form.

2. This is the most common and important resistance mechanism for Aminoglycosides

3. enzyme modification tends NOT to affect Amikacin

Front 126

Aminoglycoside Resistance
(altered ribosomal target)

Back 126

1. the bacterium changes its ribosome so the drug can’t bind

2. may cause ribosomal malfunction, so it has its cost

3. an uncommon resistance against Aminoglycosides

Front 127

Aminoglycoside Toxicity

Back 127

1. Ototoxicity: results in hearing loss and/or tinnitus; vestibular damage leads to vertigo

2. Nephrotoxicity

Front 128

Aminoglycoside Ototoxicity

Back 128

1. results in hearing loss and/or tinnitus;

2. vestibular damage leads to vertigo

3. Idiosyncratic or dose-dependent
a. Idiosyncratic/genetic origin may result in immediate and permanent deafness with one dose. This complication may be the result of genetic disposition, as incidence has been observed in families with mutations in mitochondrial ribosomal genes. Therefore you may want to get a family Hx of reactions to this drug if possible; seen in some Asian families (particularly among Chinese)
ii. Mechanism: Altered NMDA receptors in brain and cochlea result in reactive oxygen species that damage the host’s mitochondria.
iii. Dose-dependent ototoxicity is probably due to chronic use of aminoglycosides

Front 129

Aminoglycoside Nephrotoxicity

Back 129

a. Dose-dependent and length-dependent; occasionally idiosyncratic

b. Prolonged exposure- Mechanism: binds megalin in proximal tubules resulting in calcium channel disruption and cation influx. Accumulation results in damage to kidney in proximal tubule

Front 130

Linezolid

Back 130

1. an oxazolidinone

2. Mechanism: Inhibits 50S from binding

3. Properties:
a. Administered IV or PO
b. Bacteriostatic (Abx Table)

4. Spectrum:
a. Gram + , Abx resistant bacteria:
i. Methicillin-resistant Staphylococcus aureus (MRSA)
ii. Vancomycin-resistant Enterococcus faecium, but NOT E. faecalis. (Abx Table)

4. Has “good lung penetration” (LYN, Abx Table, ppt.)

5. Resistance: Alteration of ribosomal binding site so Linezolid can’t bind
a. Resistance seen with long-term use
b. Has been noted with increasing frequency in the last five years

5. Toxicity:
a. Hematologic- Bone marrow toxicity; particularly thrombocytopenia with long-term use.
b. Neuropathy- due to mitochondrial toxicity
c. GI irritation (Abx table)
d. Cytopenias with long term use (Abx table)

Front 131

Tetracyclines and Glycyclines
(Mechanism)

Back 131

1. Binds reversibly to the 30S subunit, preventing tRNA binding to the A site

2. Have chelating action (Abx Table)

Front 132

Tetracyclines and Glycyclines
(Properties)

Back 132

1. There are four rings, with a ribosomal binding side and metal binding side.
a. “Good old fashion tetracycline” should not be taken with milk and/or calcium-rich foods, because Ca2+ will bind to metal binding site and the Abx will not be absorbed.

2. Are being used more commonly as S. aureus infections increase, and the apprehension to over-use Linezolid.

3. Long acting: Thereby reducing incidence of non-compliance

4. Bacteriostatic (Abx Table)

Front 133

Tetracyclines and Glycyclines
(spectrum)

Back 133

very broad, including Gram -, Gram +, anaerobes; including Chlamydia

Front 134

Tetracycline

Back 134

1. PO

2. Broad spectrum; frequent dosing (QID)

3. Major indication is for acne

4. Resistance is widespread, so it is rarely used

Front 135

Doxycycline

Back 135

1. A tetracycline

2. Broad spectrum; BID dosing

3. VERY EFFECTIVE AGAINST INTRACELLULAR BACTERIA

4. IV/PO

Front 136

Minocycline

Back 136

a. Broad spectrum; BID dosing

b. Very effective against S. aureus; commonly used for skin infections

c. IV/PO

d. a tetracylcine

Front 137

Tigecycline

Back 137

a. Very broad spectrum; BID dosing

b. Particularly useful against resistant bacterial strains

c. Binds more tightly to the ribosome than tetracycline (PO), therefore shows less resistance via efflux.

d. Does NOT treat Pseudomonas.

e. IV only

f. actually a glycycline - slight modification of tetracycline

Front 138

Tetracycline Resistance Mechanisms

Back 138

1. Efflux Pump
- main resistance mechanism
- particularly effective if tetracycline is not binding to the ribosome strongly.

2. Ribosomal protection
- bacterial organism produces a molecule that is homologous to the ribosomal protein that tetracycline is supposed to bind. This molecule has a higher affinity for tetracycline, thus inhibiting its binding to the ribosome
- Since tetracycline binds reversibly, presence of this molecule can actually pull tetracycline off of the ribosome, then work together with the efflux pump to get it out.

3. Modification of Abx: altering tetracycline

4. Modification of Abx target: altering the ribosome

Front 139

Tetracycline and Glycycline Toxicity

Back 139

1. bind metals, which may cause teeth and bone malformation in the fetus

2. contraindicated in children under 8 years of age, but again, if facing a high risk illness, they may be the best alternative (e.g. Rocky Mtn. Spotted Fever).

3. ring structure captures photons, which can cause photosensitivity reactions (e.g. sunburns)

Front 140

Chloramphenicol

Back 140

A. Mechanism: reversibly binds 50s, blocking the A site

B. Properties: A very old, very cheap, broad spectrum, bacteriostatic Abx: used commonly in developing countries

C. Spectrum: Broad spectrum activity

Front 141

Chloramphenicol Resistance

Back 141

1. Chloramphenicol Acetyl Transferase (CAT) enzyme adds acetyl groups to Chloramphenicol, so it can’t bind the A site.

2. Resistance is increasing

Front 142

Chloramphenicol Toxicity

Back 142

1. Dose-dependent
- reversible anemia due to bone marrow suppression; suspend treatment if this occurs.

2. Idiosyncratic (dose independent)
- irreversible aplastic anemia - requires bone marrow transplant. Therefore it is rarely used in the U.S.

Front 143

Macrolide/Azalide/Ketolide
(Mechanism)

Back 143

1. reversibly binds the 50S in its tunnel region, thereby inhibiting peptide elongation

2. Accumulates inside cells, particularly phagocytes, making them effective Abx against intracellular pathogens

Front 144

Macrolide/Azalide/Ketolide
(Properties)

Back 144

1. Anti-inflammatory effects as a result of its modulation of phagocytic response: Therefore it can be helpful in treating certain inflammatory disease states (in addition to its role as an Abx)

2. Bacteriostatic (Abx Table)

3. Complex ring structures
-the basic structures of Macrolide, Azalide, and Ketolide are the same, but the base structure is modified; this results in differences in resistance.

Front 145

Pneumonia caused by Strep

Back 145

macrolide may help because of its anti-inflammatory response

Front 146

patients with cystic fibrosis

Back 146

those given a macrolide (azithromycin) in combination with a drug against Pseudomonas have better lung function due to reduced inflammation.

Front 147

Macrolide/Azalide/Ketolide
(spectrum)

Back 147

1. Broad spectrum, but mostly Gram +

2. Gram – bacterium are susceptible in theory, but have developed resistance to these drugs

Front 148

Erythromycin

Back 148

1. (IV/PO)

2.Macrolide/Azalide/Ketolide

3. Effective against respiratory intracellular pathogens and Gram + bacteria

4. Also against Gram – organisms (e.g. Helicobacter pylori, Campylobacter) and intracellular pathogens (e.g. Mycoplasma, Chlamydia, Legionella)

5. QID dosing; therefore reduces compliance, and as a result, is not commonly used.

6. Resistance is increasing

Front 149

Clarithromycin

Back 149

1. Macrolide/Azalide/Ketolide

2. Less resistance than Erythromycin due to stronger ribosomal binding

3. Spectrum: Same as with Erythromycin
i. In addition, it is effective against atypical Mycobacteria infections and therefore commonly prescribed for HIV+ patients

4. BID dosing

5. PO

Front 150

Azithromycin

Back 150

1. Macrolide/Azalide/Ketolide

2. (IV/PO);

3. commonly known as Z-Pack (manufactured by Pfizer)

4. Can be given as a single-dose; particularly effective for those with Chlamydia infection

5. Daily dosing; less GI discomfort

Front 151

Telithromycin

Back 151

1. Macrolide/Azalide/Ketolide

2. PO

3. Resists efflux pump; does not induce methylation

4. Daily dosing; good against respiratory pathogens, however….

5. Liver toxicity is a major problem with this drug. Problems were not seen in original studies.
i. May be pulled off the market soon due to its toxicity

Front 152

Macrolide/Azalide/Ketolide
(Resistance)

Back 152

1. is common among Gram – bacteria
2. Resistance among Gram + organisms is increasing due to the increasing use of Z-packs,

3. Mechanisms of resistance:
a. Efflux pump
b. Altered binding site - Methylation of sites on the ribosome to prevent macrolide binding
- Induced- when Abx is present
- Constitutive- occurring all the time
c. Altered tunnel morphology- not common

Front 153

Macrolide/Azalide/Ketolide
(Toxicity)

Back 153

1. Causing GI problems (this group of Abx increases motility and peristalsis which can lead to nausea and vomiting), and reversible hearing loss; discontinue treatment in these cases

Front 154

Clindamycin

Back 154

1. a lincoamide

2. Binds in the same general area as macrolides

3. Spectrum
i. Gram positive (streptococci (strep) and staphylococci (staph)) and anaerobic (increasing resistance with the anaerobes) organisms
ii. Use for oral infections as well as strep and staph skin infections

4. Resistant to the effects of the efflux pump BUT NOT alteration of the ribosome target

5. Turns off toxin production

6. inducible methylation

Front 155

Clindamycin
(Side Effect)

Back 155

ii. Clostridium difficile colitis

• Killing all of the anaerobes and gram positives in the gut (normal flora) with this drug causes only resistant bacteria to live.

Many C. difficile are resistant to Clindamycin and this leads to colitis

Front 156

Streptogramin (side effects)

Back 156

(“mitochondrial toxicity type things”)
i. Myalgias
ii. Arthalgia

Front 157

Streptogramins (Quino/Dalpo)

Back 157

a. Large molecules that target the same area as the macrolides and Clindamycin

b. Inhibit chain elongation of the peptide at the ribosome

c. Class used in animal feed

d. IV formulation

e. Gram positive spectrum (especially resistant ones) but not Enterococcus faecalis

Front 158

Resistance to Streptogramins (and in general to antibiotics

Back 158

i. Efflux
ii. Modification of drug
iii. Modification of ribosome

Front 159

Clindaymycin
(inducible methylation)

Back 159

1. Doesn't induce methylation of target ribosomes quickly

Front 160

Erythromycin
(inducible methylation)

Back 160

an excellent inducer of the methylase gene (erythromyocin ribosome methylase- erm gene).

Front 161

D test (double disk diffusion)

Back 161

1. uses Erythro’s induction of the erm gene

2. streak plate with organism and put one disk of erythromycin and one disc of Clindamycin on plate

3. you will see a zone of inhibition (where Clindamycin was able to kill the organism) and a cut off (the zone looks like a D) where Erythromycin induced methylation which causes Clindamycin not to be an effective killer.

4. If the erm gene is not there and the mechanism of the resistance to Erythromycin is through the efflux pump then you will have a complete zone of inhibition around the Clinda disk

5. If you are D test positive then you are going to have potential failure with Clindamycin because of the methylation that can occur granting the organism resistance

USE ERYTHRO TO SEE IF BACTERIA HAVE METHYLATION GENE THAT CAN BE INDUCED QUICKLY

Front 162

Nucleic Acid targets

Back 162

1. Quinolones
2. folate metabolism - trimethoprim sulfa
3. Rifampin

Front 163

Quinolones
(overview)

Back 163

1. prevents DNA replication

2. has a DNA binding side, a stacking side, and 2 enzyme binding sides
- There is a base Quinolone structure and then the side chain identifies its spectrum, pharmacokinetic characteristics, and toxicities
- are like beta lactams in that there is a base structure and side groups which determine specificity (in this case which DNA Gyrase or Topoisomerase genes are more susceptible).

3. Quinolones all end in “-floxacin

4. Popular since they are inexpensive and have good tissue penetration.

Front 164

Quinolones
(Mechanism)

Back 164

1. Concentration dependent killers – More drug = more killing

2. IV and PO forms

3. Increasing resistance due to mutations in the target genes. The Gyrase and Topo genes have mutations in the binding site which allows the organism to replicate its DNA without drug interference.

Front 165

Quinolone
(Side Effects)

Back 165

1. increased incidence of tendon rupture (especially with extended use).

2. There is also a fear of bone deformities if used for children or pregnant women.

3. Also, there are risks of QT prolongation in the heart.

4. many of them but they are thinning themselves out as they come on the market and side effects are discovered… then they are taken off of the market

Front 166

Ciprofloxacin

Back 166

1. the first very useful quinilone.

2. a gram negative spectrum including Pseudomonas but there is increasing resistance to it.

3. also used for Anthrax (B. anthracis) and STD’s except syphilis and possibly gonorrhea.

4. most potent with gram negative rods.

5. There is urinary excretion (can use for UTI’s)

6. and it’s given BID

Front 167

Levofloxacin

Back 167

1. one of the most popular quinolones

2. can be used for respiratory infections and urinary infections

3. a gram negative spectrum (for Pseudomonas only at high doses).

4. good for respiratory pathogens like Legionella, Mycoplasma, and Chlamydia.

5. Also used for UTI’s since it is excreted in the urine.

Front 168

Gatifloxacin

Back 168

1. decreasing in use and is not as important. s

2. spectrum is similar to Levofloxacin but is used even less for Pseudomonas and used more for gram positive and anaerobes.

4. It has urinary excretion

5. uses daily dosing.

6. Might prolong QT length, also some issues with diabetes.

Front 169

Moxifloxacin

Back 169

1. has the same spectrum as Gatifloxacin

2. has less urinary excretion with daily dosing.

3. detailed as the drug for respiratory tract infections and not so much for UTI’s.

4. A lot of it is being used!

Front 170

Clinafloxacin

Back 170

probably not come to market but as you get more quinolones the spectrum will target less gram negatives and more respiratory pathogens since there are many more respiratory infections that they can be used for.

Front 171

USE QUINOLONES SPARINGLY

Back 171

1. great drugs but are subject to much abuse!

2. There is decreasing susceptibility of UTI’s to quinolones.

3. Only 75% of Escherichia coli from UTI’s are susceptible to quinolnes at a local hospital when it should be upwards of 90%.

Front 172

Trimethoprim-sulfa

Back 172

1. a folate antagonist that works through a two step inhibition to stop folinic acid synthesis

2. spectrum is broad (but does not include strep or Pseudomonas). It can be used for Pneumocystis.

Front 173

Trimethoprim-sulfa
(side Effects)

Back 173

1. (because of the ring structures) include a rash with phototoxicity.

2. It used to be given for travelers diarrhea.

3. erythema multiforme which is a particularly serious condition.
- It can rarely go to toxic epidermal necrolysis which causes the skin to slough off completely.

4. Renal toxicity is common (especially in patients with preexisting problems).

5. Hepatitis is another problem.

6. In high doses there might be hyperkalemia because it will block renal excretion of potassium. So liver and kidney function along with potassium levels are often tested when using this drug.

7. Increasing resistance in E.coli. (75% are resistant to quinolones.)

Front 174

Drugs that inhibit Dihydropteroate synthetase

Back 174

Sulfa, PAS, and Dapsone

Front 175

Drugs that inhibit dihydrofolate reductase

Back 175

trimethoprim

Pyramethamine

Front 176

Rifampin

Back 176

1. An RNA polymerase inhibitor with a broad spectrum for staph and Mycobacterium

2. It develops a high intracellular concentration

3. Resistance can develop rapidly. A single mutation can cause resistance so this is why it is ALWAYS GIVEN IN COMBINATION!

4. Side effects are
- hepatitis,
- orange secretions/urine (which is a way to monitor patient compliance) which are not harmful,
- and induction of P450 which alters metabolism for many molecules. Always check patient’s drugs for cross reactivity!

Front 177

Rifabutin

Back 177

1. a rifampin-like drug that has less P450 induction.

2. It is often used for HIV for this reason

Front 178

Rifapentin

Back 178

not often used in this country. (Not important)

Front 179

Metronidazole

Back 179

1. comes into the cell and be modified by PFOR before it can cause DNA fragmentation.

2. Spectrum
- anaerobes and
- C. difficile
- as well as Amoebae (Giardia, Entamoeba, and Trichomonas).

3.PO or IV

4. It has good tissue penetration.

5. Side effects include:
- the antabuse reaction. So alert your patients that will be outpatient to not drink alcohol or they will get sick!
- Can also cause neuropathy
- as well as a metallic taste (dysguesia)
- and black urine (not common).

Front 180

Nitrofurantoin

Back 180

1. The mechanism of action is unclear but it is thought to work in a similar way to Metronidazole in that it gets absorbed and changed (reduced) by PFOR to cause oxidative injury.

2. It is useful for lower urinary tract infections since it concentrates in the urine.

3. Spectrum
- gram negatives
- NOT including Proteus or Pseudomonas.
- also useful for Enterococcus.

4. Side effects include
- pulmonary infiltrates/fibrosis
- and eosinophilia.

5. It is used more often now because of Vancomyocin resistant Enterococcus infections.

Front 181

Mupirocin

Back 181

1. Topical application

2. It is very good against gram positives including Staphylococcus.

3. Frequently used for boils or impetigo

4. It binds tRNA-isoleu to inhibit protein synthesis

5. There is increasing resistance to Mupirocin.

6. MRSA epidemic is trying to be controlled. Mupirocin can be used in part for this.

Front 182

Staphylococcus

Back 182

1. characteristic look of grapes

2. cooci; thus round

3. Gram +

4. major species
i. Staph. epidermidis
ii. staph aureus
iii. staph saprophyticus

5. Two categories
i. coagulase positive
ii. coagulase negative

6. all are catalase positive

Front 183

other organisms that staph is related to

Back 183

1. Enterococcus faecalis,

2. Listeria monocytogenes,

3. Bacillus subtilis,

4. Clostridium botulinum,

5. and Escherichia coli

Front 184

Staph. aureus

Back 184

Coagulase positive staph

Front 185

S. epidermidis

Back 185

1. Coagulase-negative Staph

2. most common

Front 186

S. lugdunensis

Back 186

1. Coagulase-negative Staph

2. one of most virulent and can cause disease similar to S. aureus

Front 187

S. saprophyticus

Back 187

1. Coagulase-negative Staph

2. often involved in UTIs

Front 188

coagulase test

Back 188

If you take plasma and put it in a test tube, S. aureus will clot the plasma and thus it is termed coagulase positive

Front 189

Beta Hemolytic

Back 189

1. S. aureus is Beta-Hemolytic, as are most all of Staph species

2. it will appear yellow on the plate

Front 190

Alpha (partial) hemolysis

Back 190

appears green on the plate

Front 191

Gamma hemolysis

Back 191

presents with no color due to no hemolysis

Front 192

catalase

Back 192

1. all staphylococci are catalse positive

2. an important virulence factor

Front 193

Staphlyococci
(Locations)

Back 193

1. Present in nose, axilla, groin, needle users, pets, people with skin problems

2. Transmission via people in close quarters, sports teams, prisons

3. Transfer of particles from nose to parts of body and room is rampant and environmental transmission is something very important to keep in mind

4. Colonization stays fairly low until grade school levels then it spikes and slowly declines as we age
i. Men are more colonized than women

Front 194

Biofilm

Back 194

1. a key virulence factor for staphcocci

2. nutrients can flow under the top of the "mushroom" and pieces can shed off

3. develops a matrix within itself and other organisms to live in a community

Front 195

Staph Typing

Back 195

1. Phage typing- different types of phage attach to different strains of staph

2. MultiLocusEnzymeElectrophoresis- types different enzymes as enzymes move differently depending on strain; old and labor intensive but is the gold standard for typing

3. PulseFieldGelElectrophoresis- chromosomal DNA banding patterns on gel correlate with strain

4. MultiLocusSequenceTyping

5. StaphProteinA typing- virulence factor with a lot of mutations

6. Ribotyping- rRNA types differ among strains

Front 196

Staph Virulence factors

Back 196

1. biofilm

2. catalase positive

3. adhesins

4. toxins

5. Protein A

6. invasins

7. microcapsule

Front 197

staph cocci adhesins

Back 197

cell bound proteins that attach to fibrin, fibronectin, or damaged tissue

Front 198

staph cocci Toxins

Back 198

releases toxins that lead to cell membrane damage, toxic shock, exfoliation, or emesis

Front 199

Protein A

Back 199

Binds the Igs by the Fc portion to prevent bacteria from being recognized by Abs

Front 200

Staph cocci Adherence

Back 200

1.clumping factor

2. coagulase + Fibronectin binding proteins - act together to cause clotting and then allowing organism to settle in

3. Biofilm - takes about 24 hours from the time you bind the surface for the biofilm to form, and allows staph to live on prosthetic devices

4. Adherence model
i. bacteria is attracted to the surface through Van der Waals forces or hydrophobic interactions and can also bind to receptors

ii. Bacteria aggregate and clump and biofilm begins to form which replicates, remodels, and spreads

Front 201

Extracellular life to avoid immunity

Back 201

1. Use of Protein A to bind Igs

2. Capsule- helps prevent opsonization and phagocytosis along with binding of the Fc receptors

3. Toxins

Front 202

Staph cocci toxins

Back 202

1. Exotoxins (enzymes, hemolysins, leukocidins)
• These destroy tissue, RBCs, and WBCs causing inflammation

2. Superantigens (cytokine production, enterotoxins)
• “overreaction” by the immune system as there is a stimulation of a very large # of T cells and cytokine release

3. Teichoic acid (cytokine production, leukocyte)

Front 203

Intracellular life of staphylococci

Back 203

1. It can hang out in the phagolysosome until it produces an alpha-toxin which causes the cell to lyse and releases the replicated staphylococcus which infects more cells and cycle continues

2. Catalase is important in this process because it is what helps it live in this environment without being destroyed

Front 204

small colony variant

Back 204

hangs out in the phagocyte for months or even years producing no alpha-toxin until a mutant arises that finally produces an alpha-toxin and kills the cell and spreads
i. These are harder to culture (and form small colonies) and harder to kill

Front 205

Structural (cell wall bound) virulence factors

Back 205

1. Peptidoglycan,

2. capsule,

3. biofilm,

4. clumping factor,

5. fibronectin binding protein,

6. protein A,

7. collagen binding protein,

8. teichoic acid

Front 206

Exoproteins and Virulence

Back 206

i. Hemolysins- damage tissue at infection site

ii. Proteases- destroy tissue

iii. Coagulase- causes clumping, enhances fibrin deposition and abscess formation, correlates with virulence

iv. Spreading factors- destroy extracellular matrix
• Hyaluronidase- degrades proteoglycans
• Staphylokinase- degrades fibrin

v. Lipases and protease V8 destroy host defense

vi. Enterotoxins- products of lysogenic conversion

Hint 206

HPC SLE

Front 207

Review of Superantigen story:

Back 207

1. APC produces IL-1 and TNF which induces fever;

2. CD4 produces IL-2 and INF which causes nausea, vomiting, diarrhea, rash, red mucous membranes;

3. another good symptom is capillary permeability and desquamation;

4. also leads to B cell suppression which allows bacteria to thrive and continue cycle eventually leading to shock

Front 208

Enterotoxins

Back 208

1. super antigens

2 Neurotoxins

3 Damage gut

4 Toxic Shock Syndrome Toxin-

5. Exfoliative Toxin- chromosomal or plasmid genes; could be a protease as well and could induce host cell metalloproteinases in skin

Front 209

Toxic Shock Syndrome

Back 209

new DNA regulated by oxygen exposure and low Mg++

Front 210

Antibiotic Resistance
(staphlyococci)

Back 210

1. Beta-lactamase

2. Vancomycin resistance (VRSA)

3. Efflux pump

4. Erm ribosome methylation- altered antibody binding site

5. Quinolone resistance

Front 211

Quorum sensing

Back 211

Gram-positive organisms produce a peptide that is basically a pheromone and release it and a receptor is responsible for recognizing the peptide

Front 212

Quorum sensing
(staphylococci)

Back 212

1. Agr molecules can induce activation or inhibition of Staph organisms
i. an inducer (peptide) binds its receptor and causes signal transduction which activates DNA binding proteins, ultimately turning on (or inhibiting) gene expression)

2. Agr inhibition potential theory
i. improper fit leads to inhibition while proper fit leads to induction, other species may inhibit the Staph in a competitive inhibition manner
a. ideally this is a good target for treatment because manipulation of these switches could allow you to turn off the disease causing genes

3. over time an Agr negative strain will continue to produce cell wall protein and not make the switch to exotoxin production
i. This shows the Agr system is very important to the organism in its virulence

Front 213

Host Defenses

Back 213

A. Phospholipase A2- kills bacteria particularly in eyes and secretions
B. Phagocytosis- complement or antibody chemotaxis of neutrophils, opsonization occurs, intracellular killing of bacteria via production of oxygen radicals

Front 214

Conditions leading to S. aureus infections

Back 214

A. Skin damage: burns, cuts, sutures, cannulas

B. Reduced chemotaxis: burns, diabetes, cancer

C. Reduced phagocytosis: diabetes, neutrophil defect, immunoglobulin defficiency

D. Age: very old and very young

Front 215

Sites of infections

Back 215

A. Brain and Eye

B. Endocarditis

C. Scalded skin syndrome (toxin)

D. Pneumonia- generally had a respiratory tract infection

E. Food poisoning (toxin)

F. Toxic Shock Syndrome

G. Pyoderma- soft tissues

H. Bone/Joint infection

Front 216

Staphylococcus aureus Pyodermas

Back 216

1. pus forming infection of the skin, superficial processes

2. Folliculitis

3. Faruncles

4. Carbuncles

5. Impetigo

6. Paronychia

7. Cellulitis

8. Eye infections

Front 217

Folliculitis

Back 217

1. hair follicles infected, usually related to multiple organisms which include s. aureus

2. Usually you host defense mechanism take care of this, as soon as the pus is drained, it heals (LYN).

Front 218

Faruncles

Back 218

boil

Front 219

Carbuncles

Back 219

multiple skin lesions (boils/faruncles) connected by sinuses in the connective tissue (a honeycombing effect)

Front 220

Impetigo

Back 220

1. crusting vesicle formation of the skin, very superficial.

2. S. aureus and S. pyogenes are the two major causes

Front 221

Paronychia

Back 221

infection of the nail bed. Usually on sides or underneath

Front 222

Cellulitis

Back 222

1. spreading connective tissue infection, usually below the epidermis. May start superficially as one of the above that spreads deeper

2. If infection involves the fascia, its called "fascitis" – the single serious pyoderma Dr. Fig mentioned is necrotizing fascitis – a surgical medical emergency

Front 223

Eye infections

Back 223

1. Stye – eyelid gland infection (hordeolum)

2. Blepharitis – eyelid infection

3. Keratitis – corneal infection, can be severe, may lead to blindness

Front 224

Metastatic Staphylococcus infections

Back 224

1. diseases affecting deeper structures and are of greater clinical concern.

2. spread
a. Skin --> blood --> heart/bones/brain
b. sinuses (from the pesky staph colonies in the nose_ --> brain

Front 225

the most important complication of a Staphylococcus aureus pyoderma

Back 225

Spread of infection from skin or nose colonies

Front 226

Osler's nodes

Back 226

1. manifestations of the infection,

2. septic emboli resulting from endocarditis,

3. often tender

Front 227

Janeway lesions

Back 227

also embolic lesions but nontender

Front 228

S. aureus in the bones

Back 228

comparison of joint spaces, at 0 and 35 days of infection – note obvious destruction of L2 vertebra, bone growth (exotoses) on L2/L3, and significant compression of joint space. (slide 74)

Front 229

Staph food poisoning

Back 229

1. "Picnic-sickness:" classic example (LYN)

2. S. aureus grows in protein-rich foods (mayo, milk eggs, etc.), reaching nearly a million or more CFU per gram.

3. Staph from nose --> hands --> Auntie Mae's chicken salad --> into your tummy = some q.t. time with your toilet

4. Toxin is released into food

5. "Ingest toxin for lunch and vomit for supper

Front 230

Staph toxin released into food

Back 230

1. Causes a super antigen reaction and is toxic to gut and stomach nerves

2. Multiple serotypes, lysogenic phage products

3. Heat stable 60º for 30 minutes

Hint 230

Think, that you're eating it... so it's an enterotoxin because you want it to be toxic to the gut... which is a superantigen

Front 231

Course of staph food poisoning

Back 231

1. Will have vomiting and diarrhea in 2-6hrs – fast process after ingestion of food

2. NO fever and after approximately 24 hrs, patient recovers without therapy, except if dehydrated (a cause of concern in the very young and old).

Front 232

Toxic shock syndrome

Back 232

Another super-antigen mediated phenomenon, stimulating uncontrolled immune response, systemic actions

Front 233

Toxic shock syndrome
(Manifestations)

Back 233

1. Skin manifestations

2. Fever – early on until day 2

3. Pain – persisting throughout

4. Hypotension – until day 4, due to cytokine production

5. Confusion – due to cytokine production

6. Headache - early

7. Diarrhea – during first week

Front 234

Toxic shock syndrome
(Skin Manifestations

Back 234

1. erythroderma (redness of skin) – day 1 to 2 

2. erythematous membranes – day 2 thru 4, peaking at day 3

3. desquamation – five days later

4. leads to eventual hair and nail loss (60 days out)

Front 235

Strawberry tongue

Back 235

1. bright red, looks like a strawberry, indicates a toxogenic process

2. seen in TSS, but also in scarlet fever (a streptococcus disease) and Kawasaki disease

3. caused by erythrematous membranes

Front 236

TSS incidence has dropped due to

Back 236

discontinuation of super-absorbant tampons.

Front 237

Scalded skin syndrome

Back 237

1. release of S. aureus exfoliative toxin,

2. usually seen in babies

3. See massive sheaths of skin lost, not very common but extremely devastating because it involves the loss of an important part of the innate immune system – the skin barrier.

4. Toxin produced during a rather limited infection from either a plasmid or chromosomal toxin gene, this condition is typically reversible with antibiotic therapy

Front 238

Exfoliative Toxin A and B.

Back 238

1. Exfoliative Toxin A: 24 KDaltons, stable @ 100C, labile EDTA and chromosomal DNA

2. Exfoliative Toxin B: 24 KDaltons, labile @ 60C, stable EDTA and plasmid DNA

Front 239

Other serious infections

Back 239

1. Joint infections – septic arthritis
a. Most common cause of septic arthritis is S. aureus infection

2. Muscle infections – pyomyositis (abscess in the muscle)

3. Bacteremias

4. Arteritis – inflammation/infection of artery

5. Pneumonia – nosocomial, occasionally community-acquired (classically post-influenza)

6. Meningitis/brain abscesses – from both embolic phenomenon or directly from nasal sinuses

7. Device related infections – device contaminated from surface of skin or human manipulation with S. aureus, production of biofilm on device leads to bacteremia in patient and infectious emboli flowing to other sites such as bones or brain.

8. Parotitis – usually seen in people who breathe with mouth open or have stones in salivary ducts, most common identified cause from S. aureus.

Hint 239

JMB and pulsless michael don't pair

Front 240

Antibiotic susceptibility of S. aureus

Back 240

1. Oxacillin or Nafcillin: drug of choice if they are susceptible (only 30% of strains in our pop. still susceptible, LYN)

2. Cephalosporin: used if another organism is possible or involved, will not be as good as prior two, but close.

3. Alternatives:
i. Minocycline, clindamycin, moxifloxacin, and other antibiotics usually are effective for MSSA strains - Not recommended for use routinely, should be spared because of resistance.

ii. Clindamycin, minocycline or sulfa-trimethoprim (usually w/ rifampin) for outpatient MRSA strains

iii. Vancomycin, Linezolid, Synercid, Daptomycin for serious MRSA infections
a. Know drug characteristics! For example, Daptomycin can't be used if infection is in lung or urine
b. Vancomycin is the "be all-end all," Linezolid good too, but developing some resistance. Daptomycin good but must note location of infection. Used only in serious infections because they work (little resistance…yet) and they are new, therefore, expensive (LYN)

Hint 240

Noa

Front 241

Treatment of Staph aureus

Back 241

1. Must treat for at least two weeks – less than this creates a greater chance of relapse

2. If prolonged infection, may treat for up to 6+ wks

3. Removal of devices, if possible. Why? Because of the biofilm. If a device is kept in, the focus of infection is retained and the infection will not be cleared.

4. Look for the pus and drain it! – First treatment for S. aureus carbuncle is complete drainage, not Abx. Open up that abscess with a knife even before Abx treatment. As a fourth year, it is important not to be timid when lancing the thousands of boils you'll be given. As Dr. Fig puts it – you gotta "filet" it. Don't worry though, we will get plenty of practice down the road in the wards.

5. Watch out for resistance!

Front 242

MRSA no longer hospital limited: increasingly more common

Back 242

1. About 40% of populace in parts of Australia

2. About 40% of populace in parts of Honolulu, including military (around '98-'99)

3. Nursing homes and outpatients (<75%) in staph infections

4. 1-3% colonization in general population, for someone who has never been in medical care – highly unlikely so colonization rate, in most, is a bit higher

Front 243

VISA fairly rare but emerging problem

Back 243

1. also termed glycopeptide-intermediate S. aureus,

2. this strain shows resistance to all glycopeptide abx's, including vancomycin,

3. was first found in Japan and now seen in hospitals in England, France and U.S

Front 244

Control of MRSA spread to community

Back 244

A. Colonized patient has MRSA in nose and creates a CLOUD of bacteria in the environment – which spreads out to three feet all around during a sneeze and seems to be the maximum distance for transmission, which is why classrooms/army barracks are now arranged with at least three feet between every chair/bed

B. Treating the nose of colonized patients may soon be done in an aggressive manner: reports show initial effectiveness
1. Mupirocin, a topical Abx, 80%-90% effective unless have some resistance, although re-colonization does occur
2. Lysostaphin, an enzyme currently in trials. (the enzyme is Staphylococcus simulans metalloendopeptidase, it functions as an antimicrobial agent– wikipedia)
3. In Europe and increasingly in the U.S. – "search and destroy"
a. Identify everyone w/ MRSA colonization and eliminate them (the colonies not the people! – decolonize the people) with Abx agents

Front 245

staph a. vaccine

Back 245

1. StaphVAX polysaccharide vaccine
a. Effective in dialysis patients
b. Phagocytosis
c. Prevents bacteremia - Preventing invasion not colonization. Idea of using targets other than preventing the infection all together, a carbuncle is OK, no big deal but let's keep the infection out of the blood – where we get the bigger problem

2. Other toxin or adhesion targets may be possible.

Front 246

S. epidermidis

Back 246

1. Normal flora of skin in high numbers, frequent contaminant of specimens

2. Opportunist, enter wounds mainly

3. Adheres to implants, forms biofilms (slime) - catheters, joint replacements, heart valve replacements with hardware

4. Release proteases and lipases – contribute to virulence

5. Major cause of prosthetic device infections

6. Almost always oxacillin-resistant. (in our population) so first tx of choice - Vancomycin

Front 247

Coagulase negative Staphylococcus

Back 247

1. S. epidermidis - most common

2. S. ludgenensis - ones of the most virulent
a. Can cause disease that looks just like S. aureus, important to know that a coagulase negative Staphylococcus strain can be as virulent as S. aureus when receiving culture results from lab – don't underestimate it.

3. Treatment
a. Removal of device frequently necessary!! "gotta take out the hardware"
b. Vancomycin first choice, but others OK too:
i. Maybe linezolid, daptomycin, others as tested
ii. May add rifampin and/or gentamicin

4. Intravenous catheter infections – potential sources of contamination

Front 248

Where would you expect the bacteria to come from if you had IV catheter infection

Back 248

i. May have introduced the bug during insertion…
• Contaminated catheter –look for colonization on the tip, occurred pre-insertion
• Transcutaneous migration from the surface of skin – occurred at time of insertion


ii. Or from some other place that settled on the catheter already in place
• Hematogenous seeding from a distant site: preexisting bacteremia.
1. The inserted catheter in the vein elicits a foreign body reaction which cause fibrin acquisition, etc. creating an environment favorable for staph adherence

Front 249

S. saprophyticus

Back 249

1. 2nd most common cause of UTI in sexually active young women.

2. produces proteins that create adhesion to vaginal wall rather than in the nasal cavity as seen in S. aureus

3. adherence is the 1st step to virulence

4. Vaginal adherence accomplished by hemagglutinin

5. Organism spreads to urinary tract during sexual activity then to the bladder and causes cystitis (inflammation of the urinary bladder)

6. Adheres to urinary tract and releases urease

7. Treatment: fortunately is the same treatment as used to treat UTIs caused by other organisms (slide 110)
a. TMP-SMX
b. Quinolones

Front 250

E. coli (Escherichia coli)

Back 250

1. THE most common cause of UTIs

2. and we will see that not all strains of E. coli cause UTIs, only the ones that adhere to the vaginal wall

Front 251

hemagglutinin

Back 251

is particularly adept at adhering to vaginal epithelium which is why this organism is a major cause of UTI in sexually active women

Front 252

urease

Back 252

causes cell death and leads to kidney stone formation and damage to urinary tract

Front 253

S. Saprophyticus
(Mechanism cascasde)

Back 253

1. Vagina: anaerobic conditions --> hemagglutinin #1

2. colonization (no damage or disease) then during sexual intercourse: trauma causes bug to reach urinary bladder: aerobic condition

3. hemagglutinin #2 + urease --> infection + alkaline urine pH

4. tissue damage and (potentially) stone formation.

Front 254

Pyogenic bacteria

Back 254

1. a group of bacteria in which the hallmark of infectious process is the ability to produce pus

2. Body can also produce fever making this a pyrogenic response

3. Two basic groups:
i. Gram-positive—cause disease through production of exotoxins
a. Staphylococcus spp
b. Streptococcus spp

ii. Gram-negative—do not produce exotoxins; instead the disease process is a consequence of the host immune response to lipopolysaccharide (LPS)
a. Neisseria spp
b. Haemophilius spp

Front 255

Streptococcus

Back 255

1. can cause disease in man and many other mammals (can get some of these infections from animals)

2. Associated in gram-positive chains or as diplococci (pairs)

3. Primarily colonize the skin and mucosal surfaces

4. are generally non-invasive; however, they can become opportunistic pathogens. Some of these are part of the normal flora of the gut—if there is a break, then this can cause septicemia.

5. most dental disease is caused by streptococci

6. does not produce catalase

Hint 255

strEp = dEntal diseases

stAph produces cAtAlAse

Front 256

Streptococcus is responsible for a large number of diseases that may be grouped according to their pathogenic mechanisms

Back 256

1. Non-toxin mediated

2. Toxin and/or enzyme mediated

3. Dental associated

4. Host immune response—host responds to certain structures on the surface of the streptococci which are similar to structures that occur within the host (molecular mimicry).

Front 257

Classification of Streptococci

Back 257

1. Bacteriological Classification—primarily based on type of hemolysis exhibited by streptococci on sheep blood agar plates


2. Immunological Classification—divides streptococci into SEROGROUPS, based on the antigenic variation of cell surface associated structures

Front 258

Bacteriological Classification

Back 258

1. Beta (β) hemolytic streptococci—exhibit a CLEAR zone of hemolysis surrounding the individual colonies indicating COMPLETE lysis of the RBCs in the medium.

2. Alpha (α) hemolytic streptococci—exhibit a zone of partial/incomplete hemolysis
i. LYN: The zone around the colonies appears green due to the reduction of hemoglobin to methemoglobin.

3. Gamma (γ) hemolytic streptococci—there is no zone of hemolysis because the gamma hemolytic streptococci do not possess the hemolysin enzyme that lyses RBCs.

Front 259

Immunological Classification

Back 259

1. Classification is based on presence of a group specific carbohydrate (C-carbohydrate) or glycerol teichoic acid

2. Serogroups A, B, C, & G contain a C-carbohydrate
i. They are also beta-hemolytic

3. Serogroups N and D contain glycerol teichoic acid
i. Group D is part of the normal flora in your intestine that can get into the bloodstream with a perforation of the intestine. They can then attach to the heart muscle and you end up with subacute endocarditis (will give more details later).
ii. Group D is gamma-hemolytic

4. Each serogroup relates to a specific species (ex. serogroup A is a Streptococcus pyogenes—causes strep throat and rheumatic fever)

Hint 259

C carb = B hemolysis

Glycerol techoic acid = Gama Hemolytic

Front 260

Viridans streptococci

Back 260

1. Mostly alpha-hemolytic organisms (viridis = green) that do not have a C-carbohydrate or glycerol teichoic acid (can also be gamma-hemolytic)

2. Comprise many organisms that are members of the normal oral flora

3. S. mutans—responsible for caries.

4. The pneumococcus, Streptococcus pneumoniae, is a member of this group. It is a diplococcus

Hint 260

GAVE
- can be gamma hemolytic
- mostly alpha hemolytic
-Viridians

Front 261

Group A Streptococcus (AKA GAS) = Streptococcus pyogenes

Back 261

1. pus-producing

2. a beta-hemolytic streptococcus

3. has a C-carbohydrate on the surface—therefore, Group A

Front 262

Lysis of RBC's is caused by the secretion of 2 hemolysins

Back 262

1. SLO (streptolysin O)—oxygen labile and lyses RBCs in the interior of the agar plate
a. Important! SLO is highly antigenic and anti-SLO antibody titers are used to determine an antecedent streptococcal infection.

2. SLS (streptolysin S) – oxygen stable and is responsible for surface lysis of the RBCs
a. This is why it is good microbiological practice to undercut the sample when streaking for colony isolation. Also can enhance hemolytic activity by placing agar plate in a candle jar (jar with a candle in it that consumes all available oxygen).

Front 263

Diseases caused by S. Pyogenes

Back 263

1. Acute (suppurative) diseases

2. Non - suppurative sequelae

Front 264

Acute (suppurative) diseases

Back 264

1. symptoms appear soon after exposure to the organism (ex. pustules in throat, lesions in skin)

2. Organism causes diseases such as: pharyngitis, impetigo, erysipelas, cellulitis, vaginitis, scarlet fever, necrotizing fasciitis (flesh-eating bug), toxic shock syndrome

3. Organism may invade to cause bacteremia and septicemia (ex. necrotizing fasciitis)

4. Organisms can be cultured and treatment with antibiotics is effective

Front 265

Non-suppurative sequelae

Back 265

1. 2 serious diseases caused by streptococci pyogenes:

2. Acute Rheumatic Fever (ARF) & Post-Streptococcal Glomerulonephritis (PSGN)

3. Organisms usually cannot be cultured and antibiotic therapy is not effective
i. The process happens as an acute suppurative disease first (ex. throat infection or skin infection) --> you treat it or it may resolve itself --> then the patient begins to demonstrate symptoms (heart or kidney problems) several weeks later --> you swab but you don’t find the organism (you killed it with antibiotics or it resolved itself during the acute phase)
ii. The host has responded to a product of the s. pyogenes (we will go over this more later)

4. ASO titer (pre-pharyngeal infection)

Front 266

How does S. pyogenes cause disease

Back 266

1. Cell wall structures, enzymes and exotoxins contribute to its potential pathogenicity.

2. These components are implicated in the initial attachment of the organism to host tissues, spread of the organism, inhibition of phagocytosis, and the induction of host immune response to self tissue structures (molecular mimicry).

Front 267

S. pyogenes cell wall-associated structures associated with attachment

Back 267

1. M-protein is the most important

2. Lipoteichoic acid (LTA)

3. F-protein

Front 268

M- protein

Back 268

1. Extends from the cytoplasmic membrane thru the peptidoglycan layer (looks hairy, like fimbriae) [31].

2. Mediates attachment to epithelial cells via fibronectin.

3. Follow along with [32]. Consists of two main components:
i. The “opsonic antibody epitopes”—this part binds to your cells (epithelial cells)and produces an anti-phagocytic properties.
ii. Stalk which includes “cross-reactive antibody epitopes

Front 269

The “opsonic antibody epitopes”

Back 269

1. Highly variable binding domain (called M-types)

2. There are over 100 M-types

3. Highly antigenic—you will make antibodies to this region (ex. if you are exposed to M-type 25, you will make antibodies for M-type 25. Second exposure to M-type 25 will not result in infection. Exposure to M-type 75 will result in infection.) This is called type-specific immunity and is generated by the M-protein. As you get older, most sore throats are caused by viruses because you have built up a repertoire of antibodies that recognizes the M protein.

4. M proteins possesses anti-phagocytic properties—contributed by the opsonin antibody epitope domain by:
i. binds fribrinogen which masks C3b binding sites
ii. binds Factor H of the alternate complement pathway that can inhibit both C3 convertase and C5 convertase

Front 270

Stalk

Back 270

1. Quite constant between all the different types of Group A Streptococci.

2. The amino acid sequence in the region of the “cross-reactive antibody epitopes” is generally non-immunogenic because it is conformationally similar to the cardiac protein, tropomyosin (ie. most people do not make antibodies against this region).

3. However and unfortunately, some individuals can generate an immune response to this domain (autoimmune disease). The antibodies generated can bind to cardiac muscle protein (tropomyosin) and initiate and inflammatory response resulting in Acute Rheumatic Fever.
i. This has been shown to be genetic

Front 271

Lipoteichoic acid (LTA)

Back 271

1. Facilitates attachment of streptococci to fibronectin by a 2-way process

2. Helps orient the M protein

3. Is antigenic but does not confer immunity

Front 272

F-protein

Back 272

1. binds fibronectin, thus facilitating attachment and subsequent colonization

2. Like LTA and the M protein

Front 273

Quick Summary:

Back 273

1. The three cell surface structures which facilitate attachment of streptococcus to epithelial cells are: M protein, LTA and F protein.

2. Of the 3, only M protein confers immunity and the M-type is the basis of the concept of type-specific immunity.

Front 274

M-like proteins

Back 274

1. binds the Fc portion of IgG and IgA molecules thus making cells appear like self (disappears from immunological surveillance)

2. Analogous protein to Protein A in S. aureus

3. Binds α2-macroglobulin that can inhibit PMN proteases

Front 275

Plasminogen binding protein (PBP)

Back 275

1. binds plasminogen (major component of blood) which can then bind plasminogen activators (clot blasters) such as tPA, urokinase, and streptokinase that convert plasminogen to plasmin, a broad spectrum protease.

2. This may aid in the dissolution of host protein structures thus facilitating tissue spread in such diseases as necrotizing fasciitis, cellulitis and erysipelas

3. Plasmin is a potent activator of the alternate complement pathway; thus PBP may contribute to the inflammatory response

Front 276

Hyaluronic acid capsule

Back 276

is indistinguishable from ground substance hyaluronic acid so that encapsulated organisms tend not to be phagocytized

Front 277

C-carbohydrate

Back 277

1. basis for serogrouping

2. Immunogenic, but does not confer effective immunity (carbohydrates less effective than proteins in generating a memory immune response).

3. Antibodies to the C-carbohydrate have been demonstrated to be involved in the development of arthritis by generating an auto-immune response to joint polysaccharides.

Front 278

60kD Rheumatic Fever Associated Antigen (RFAA)

Back 278

this molecule has been implicated in the generation of antibodies that cross-react with cardiac tissue proteins that contribute to the pathogenesis of ARF in a manner similar to that for M protein

Front 279

Extracellular products of GAS

Back 279

1. Not toxins in the classical sense (e.g. diphtheria or tetanus toxin)

2. Interfere with phagocytosis, facilitate spread of infection

3. Nucleases

4. Streptokinase
a. Complexes with host plasminogen to activate plasminogen to plasmin.

5. Streptolysin—already mentioned earlier.

6. Exotoxins

7. C5a peptidase
a. Degrades C5a produced by either classical or alternative pathway to reduce inflammation and phagocyte recruitment.

8. IgA protease
a. Splits secretory IgA (sIgA) to prevent opsonization of streptococcus.
b. Important since many step infections involve mucosal surfaces.

Front 280

Nucleases

Back 280

1. DNAse A, B, C, and D—released from neutrophils and other host cells

2. Used to reduce the viscosity of pus and spread infection from abscesses.

3. Highly antigenic; anti-DNAse B titers are particularly useful in diagnosing APSGN.

1. The way you can detect an antecedent streptococcal infection is by looking for an ASO titer. This only works if you have a pharyngeal infection. If you get an impetigo infection, the SLO released by the streptococcus is absorbed by the lipids in the skin and is never presented to the immune system. This results in a blunted ASO titer. Therefore, look at the anti-DNAse B titer, because the DNAse B can get through the skin to generate an immune response. Bottom line: if you suspect a streptococcus skin infection, request a DNAse B titer instead of ASO titer.

Front 281

Exotoxins

Back 281

1. Three streptococcal pyrogenic exotoxins (SpeA, SpeB, and SpeC) are superantigens interacting with macrophages and T-cells to release IL-1, IL-2, IL-6, TNF-alpha, TNF-beta, and IFN-gamma.

2. SpeA and SpeC are encoded by lysogenic phages.

3. SpeA is indicated in the development of scarlet fever, necrotizing fasciitis, and toxic shock syndrome. Remember that s. aureus infection can also lead to TSS.

4. SpeB is present in all GAS, some strep G, and some strep C.
i. SpeB is a cysteine protease, which is responsible for massive tissue destruction and invasiveness.
ii. Associated with a highly virulent serotype M1.
iii. SpeB along with SpeA are thought to be highly involved in the spread of necrotizing fasciitis

Front 282

Non-suppurative sequelae

Back 282

1. Acute Rheumatic Fever (ARF) and Acute Post-Streptococcal Glomerulonephritis (APSGN)

2. Remember that it is a delayed reaction; the organisms themselves have disappeared

Front 283

ARF

Back 283

1. Jones Criteria [52]—used in the diagnosis of Rheumatic Fever.
NT note: He glossed over this Jones crap really fast. Don’t spend any time on it. Look at the mnemonics on [52]. This next part (D) is important.

2. The development of ARF requires antecedent infection with either group A or group G in the upper respiratory tract.
a. These are the only two groups that contain M-proteins (Group A has more than 100 M-types. Group G has only 1—M-type 12.
b. Remember, the stalk structure of the M-protein is what is contributing to the pathogenesis of ARF. It is inheritable.

3. See [54] for various theories which GAS elicits an inflammatory response that constitutes ARF

Front 284

Acute Post-Streptococcal Glomerulonephritis (APSGN)

Back 284

1. Can follow either a pharyngeal or skin infection. In the northern hemisphere, APSGN stems mostly from pharyngeal infections. However, in the tropics and sub-tropics (New Orleans included), most APSGN stems from an antecedent skin infection.

2. Associated with a very restricted number of M-types (found in groups A, C, and G). Therefore, you must be infected with a particular streptococcus with a particular M-type.

3. Occurs in epidemics

4. Many of the streptococci causing APSGN that comes from animals is in Group C.
a. People in Eastern Europe were getting APSGN drinking milk from infected cows.

5. Predominates in children and young adults—therefore, there is a possibility that immunity develops against whatever agent caused APSGN. This is an important difference between ARF (which can recur) and ASPGN.

6. Usually, damage to glomeruli is severe enough to require dialysis or transplantation.

7. Characterized by the abrupt onset of hematuria, proteinuria, fever, edema, oliguria, hypertension, headache, depression of complement factors (particularly those of the alternate pathway), and reduction of glomerular filtration.
a. If the disease is detected early enough, consumption of the alternate pathway is found. Later, consumption of the classical pathway components is also present.
i. So, early on you will see a decrease in C3 (especially C3b), whereas later in the disease C1, C2, and C4 would be reduced.
ii. An early biopsy would show C3 deposition in the glomeruli, but not Ig deposition.

Front 285

Theories to explain nephritis

Back 285

1. Circulating Ag-Ab complexes deposited in the kidney activates complement which damages the kidney.

2. Reaction of host antibody to implanted streptococcal antigens or to a modified glomerular antigen (neoantigen).

3. Initiated by the direct toxic effect of a streptococcal component and progressive disease stems from host response to new antigens.

4. Alternate theory: Nephritogenic streptococci have a unique streptokinase that has affinity for receptors in the kidney. If the streptokinase interacts with native plasminogen, it deposits in the kidney. The activation of complement produces C3b and an inflammatory response, damaging the kidney. Non-nephritogenic streptokinase is processed in the liver not the kidney.

Front 286

Streptococcus agalacticae

Back 286

1. Group B Streptococci

2. Beta Hemolytic

3. Part of the transient flora of the GI and lower GU tract of women

4. In patients of diabetes mellitus and peripheral vascular disease, it can cause skin infections in the lower extremities.

5. Primarily affects women and infants

6. Has few extracellular and cell wall associated virulence factors other than a capsule.

Front 287

Streptococcus agalacticae
(capsule)

Back 287

1. Capsule is the primary virulence factor that prevents phagocytosis.

2. Antibodies to the capsule promote opsonization which equals protection.

3. Within GBS, there are at least 7 capsular types (Although 2 of them are responsible for the 3 most common diseases).

4. If an organism has a capsule which is anti-phagocytic, you can make antibodies to the capsule; you basically have a vaccine. Many vaccines are based on capsules.

*Since there are at least 7 different capsular types, a‘cocktail’ vaccine is required to promote an antibody repertoire to these different types

Front 288

GBS is grouped into 3 Types of Disease

Back 288

1. Adult Onset

2. Early Onset Neonatal

3. Delayed Onset Neonatal

Front 289

GBS Disease: Adult onset

Back 289

1. Capsular Type II --> Adult GBS

b. Remember GBS is a part of the normal flora of the GI and lower GU tract (the GUT or Genitourinary tract) in women. 15-20% of the female population are carriers and this transient flora can give rise to Upper Respiratory Tract or URT infections.

3. When women give birth, it can be involved in Post-Partum Sepsis where GBS spreads from the vagina to surgical wounds resulting in septicemia which can lead to meningitis.

4. In women with uterine infections GBS can also cause Endometritis.

5. Additionally, 50-60% of infants borne to a carrier become infected.

6. Most common beta-hemolytic organism found in blood!
- GAS rarely invades the bloodstream.
- So if you do a blood culture and find a Gram(+), Catalase(-), chain-forming Coccus, it is likely GBS (LYN).
- Remember though that GBS rarely enters the blood stream. BUT if in a blood sample appeared Beta-hemolytic streptococci, it is more than likely GBS.

Front 290

GBS Disease: Early Onset Neonatal

Back 290

1. <5 days post-partum

2. Capsular Type III --> Early Onset and Delayed Onset Neonatal Meningitis

3. Caused by Vertical Transmission from mother

4. Risk Factors:
i. Mother was colonized with Type III GBS and has a low titer to GBS III
ii. Amniotic membrane rupture 18 hours before delivery

5. Result of GBS to Bacteremia, Septicemia, Pneumonia, and Meningitis

Front 291

Vertical Transmission

Back 291

i. Birth canal during delivery

ii. Premature rupture of membranes

iii. Disseminated maternal disease

iv. Aspiration of contaminated amniotic fluid

Front 292

GBS Disease: Delayed Onset Neonatal

Back 292

1. 60-90 days post-partum

2. Capsular Type III --> Early Onset and Delayed Onset Neonatal Meningitis

3. Caused by Horizontal Transmission (between caregivers and other infants; nosocomial)

4. To combat horizontal transmission of GBS, the mother can be given a vaccine against GBS. The resulting produced maternal antibodies will then confer passive immunity to the child. (LYN)

5. Results of GBS in Delayed Onset Disease results in the same pathologies: Bacteremia, Septicemia, Pneumonia, and Meningitis.

Front 293

Treatment for GBS is Vaccines

Back 293

1. Conjugate Vaccines

2. Development of a Polyvalent Vaccine

Front 294

Conjugate Vaccines

Back 294

1. Types II and III (are conjugated to tetanus toxoid)

2. Carbohydrates are poor in eliciting an immune response at an early age.
- This problem is solved by conjugating them to proteins.
- Therefore, the “conjugate vaccine” for GBS involved the” conjugation” to tetanus toxoid.

Front 295

Polyvalent Vaccine

Back 295

1. to all capsular types :

2. is still being developed. Again, the idea behind the use of carbohydrate capsule for vaccine is that many carbohydrates that are different from the body’s own carbohydrate, usually elicits an immune response, creating opsonizing antibodies specific for that particular capsule.

Front 296

4 GBS Diagnosis Methods

Back 296

1. Blood Agar Plate

2. Resistance: Bacitracin and STX

3. CAMP Test: GBS is CAMP(+)

4. Agglutination: using specific anti-group B antisera, tests for particular antigenic material

Front 297

Blood agar plate for GBS

Back 297

1. Colonies of GBS are usually large and mucoid with a relatively small zone of hemolysis.

2. A double zone of hemolysis may be observed on the blood plate if it is refrigerated after initial incubation.

Front 298

CAMP test for GBS

Back 298

1. GBS hemolysin by itself is NOT a powerful hemolytic agent. But when GBS hemolysin and S. aureus hemolysin work together, they produce a great amount of hemolysis.

2. CAMP test capitalizes on the synergistic hemolytic action of GBS hemolysin and Staphylococcal beta-lysin (sphingomyelinase C).

3. A single streak of suspected GBS is made perpendicular to but not touching a single streak of beta-lysin producing S. aureus.

4. If the organism is GBS there will be an arrowhead-shaped zone of synergistic hemolysis where the two streaks join.

Front 299

Group C Streptococci

Back 299

1. Humans (Streptococci Equisimilis)

2. C. Animals (Streptococci Equi, S. Zooepidemicus, S. Dysgalactiae)

3. Beta hemolytic

4. NOT associated with ARF (Acute Rheumatic Fever) - there are no M-protein structures.

5. Produces streptokinase as with GAS and GGS

Front 300

Streptococcus equi

Back 300

1. causes a disease called STRANGLES in horses

2. typified by the presence of a sore throat within 24hours

3. followed by the “eating through” of the horse’s neck by the bacteria

4. then followed by transmission to other animals

Front 301

S. Dysgalactiae

Back 301

causes bovine mastitis

Front 302

S. Equisimilis and S. Zooepidemicus

Back 302

1. can cross the species barrier and cause Post-Streptococcal Glomerulonephitis in humans.

2. In Eastern Europe, it is associated with drinking unpasteurized milk.

Front 303

Group G Streptococci (GGS)

Back 303

1. Beta hemolytic

2. No species designation (just Group G)

3. Associated with ARF (has M12 protein) and PSGN

4. Epidemiologically associated with Caribbean basin

5. Produces Streptokinase

6. Primarily a human pathogen but can infect dogs (PSGS)

7. Can cause similar suppurative infections to GAS, even though it doesn’t have GAS’s enzymes

Front 304

Group D (enterococcal and non-enterococcal) Streptococcus

Back 304

1. Non-hemolytic or Gamma hemolytic streptococci

2. They are characterized by glycerol teichoic acid serogroup (not C-carbohydrate)

3. Distinguished from other streptococci by their ability to hydrolyze esculin and grow in the presence of 40% bile salts.
- The ability to grow in the presence of bile salts gives them the advantage to survive in the bile duct and intestine.

4. Members of normal flora which commonly inhabit the skin, URT, GIT, and GUT.
- The majority of infections result from invasion by these organisms.
- Thus, they can be regarded as opportunistic pathogens.
- For example: If they get into the blood stream, they have affinity for cardiac tissue and can cause Subacute Endocarditis.

Front 305

Group D Streptococci
(Divided into 2 groups)

Back 305

1. Enterococcus

2. Non-Enterococcus

Front 306

Enterococcus

Back 306

1. E. faecalis, E. faecium, E zymogenes

2. Salt tolerant (distinguishing factor)

Front 307

Non-Enterococcus

Back 307

1. S. bovis, S. equinis

2. NOT salt tolerant

3. Sensitive to Penicillin

Front 308

Enterococcus faecalisis

Back 308

1. Frequently associated with urinary tract infections, biliary tract infections, septicemia, and endocarditis (particularly in the elderly or patients undergoing manipulation of the GI tract and the GU tract).

2. Resistance to penicillin,
- thus treatment requires penicillin and aminoglycoside (gentamicin and streptomycin) synergistic therapy.
3. In addition, these organisms can be potentially troublesome in that they possess plasmids encoded for antibiotic resistance which can be transferred to other bacteria

Front 309

Alpha-hemolytic streptococci

Back 309

1. Viridans and Streptococcus Pneumonia

Front 310

Viridans

Back 310

1. Alpha hemolytic
a. Viridians is a term used to designate streptococci that are alpha hemolytic.
b. Many cannot be classified by the C-carbohydrate or glycerol teichoic acid serogroup scheme.

2. Many species

3. Colonize the oropharyngeal cavity (30-40% of the normal or transient flora)

4. May invade the bloodstream and become opportunistic infections causing
a. Subacute Bacterial Endocarditis
b. Meningitis
c. Intra-abdominal Infections

Front 311

Mutans Group

Back 311

1. Viridians

2. Species: S. mutans, S sobrinus, S. cricetus, S rattus, S. ferus, S. macacae, S. downei

3. Main Site: Tooth surface

4. Infections: Dental Carries

Front 312

Salivarius Group

Back 312

1. Viridians

2. Species: S. salivarius,
S. vestibularis


3. Main Site: Dorsum of the tongue

4. Infections: S. salivarius is a pioneer species in plaque formation. It produces extracellular polymers from sucrose to which other bacteria attach

Front 313

Anginosus Group

Back 313

1. Viridians

2. Species: S. constellatus,
S. intermedius, S. anginosus


3. Main Site: Gingival crevice

4. Infections: Dentoalveolar and endodontic infections

Front 314

Mitis Group

Back 314

1. Viridians

2. Species: S. mitis, S. sanguis,
S. gordonii, S. oralis,
S. crista

3. Main Site: Associated with dental plaque, tongue and cheek.

4. Infections: Dental caries, endocarditis.

Front 315

Mutans is pathologic

Back 315

A dentist will ask his patient if he or she has had rheumatic fever. If yes, then the dentist will prescribe prophylactic antibiotics. Why is this done? Because these bacteria can become opportunistic pathogens, enter the blood stream, and cause endocarditis.

Front 316

Streptococcus Pneumonia, aka Pneumococcus

Back 316

1. Alpha hemolytic

2. Lance shaped Diplococci surrounded with a capsule

3. Capsule is the primary virulence factor

4. Exclusively a human pathogen spread by aerosols

5. Member of the transient flora; up to 70% are carriers

Front 317

Steptococcus Pneumia
(disease fact)

Back 317

1. Most common cause of community acquired pneumonia, particularly in the elderly.

2. Primary cause of Otitis Media (infants and children most susceptible)

3. Most common cause of bacterial meningitis in all age groups- mortality rate of 40%.

4. Major cause of sinusitis

Front 318

Facts about acquired pneumonia

Back 318

1. (350,000-570,000 cases with about 40,000 deaths /yr) As you get old, immune system goes down and opportunistic pathogen can get foothold

2. disease usually results when defense mechanisms in the lung break down (ex: antecedent viral infection or whooping cough which can compromise cilia function).

3. Predisposing factors such as splenic dysfunction, alcoholism, anesthesia, congested heart failure, and immune dysfunction can contribute.

Front 319

Causes of otitis media

Back 319

i. S. pneumonia (>50%)

ii. Haemophilus influenzae (30%)

iii. S. pyogenes (10-15%)

Front 320

Causes of sinusitis

Back 320

i. S. pneumonia (30-40%)

ii. Haemophilus influenza (20%)

iii. Moraxella catarrhalis (20%)

iv. S. aureus (20%)

Front 321

Streptococcus Pneunomia
(Cellular components involved in pathogenesis)

Back 321

a. Capsule:

b. Attachment to epithelial receptor

Front 322

Streptococcus Pneunomia Capsule

Back 322

i. Also known as SSS (soluble specific substance)

ii. Main virulence factor (anti-phagocytic)

iii. Many antigenic types (>90), like M-protein, gives rise to Type Specific Immunity
• You can be immune to one type of one capsule, and not to a pneumococcus of another capsular type.

iv. Antibodies to the capsule provide protection by enhancing opsonization

v. The capsule is the basis of the vaccine which is a cocktail of 23 capsular types that represent 90% of the pneumoccocal antigenic types that cause disease.

Front 323

Streptococcus Pneunomia
(Attachment to epithelial receptor locations)

Back 323

i. In Bronchi

ii. In Eustachian Tube:
• Leads to Otitis Media

Front 324

Streptococcus Pneunomia
(Attachment to epithelial receptor locations in bronchi)

Back 324

• Evasion of phagocytosis by capsule

• Pneumolysin inhibits neutrophil respiratory burst. Pneumolysin also causes destruction of cilia which results in cough and secondary infection

• Chemotaxis interference

• Results in spread in lung by Neuraminidase and damage to alveolar tissue by Pneumolysin which causes cyanosis and bloody sputum

• Bacteremia that leads to septicemia, then meningitis. Bacteremia and septicemia will present with fever, shock (due to peptidoglycan and teichoic acid).

Front 325

Streptococcus Pneunomia Vaccines

Back 325

a. Capsular Cocktail representing 23 of the major virulent pneumococci

b. Not effective in children <2 and elderly: the groups at highest risk:

c. Idea of a conjugate vaccine? However the logistics of attaching all 23 capsular types problematic.

d. Possible new vaccine based on a cell wall protein, PspA which is present in all pneumococci; being tested. Because it is a protein it may prove to be very effective for use in children <2 years of age.

Front 326

Neisseria characteristics

Back 326

1. Gram negative, non-motile diplococci.

2. It is nonmotile

3. Often found within PMNs

4. May be regarded as facultative intracellular parasites

5. Colonize mucosal surfaces of mammals

6. Transmission via close human contact , environmental exposure is often lethal to the organism
* In contrast, Streptococcus and Staphylococcus remain viable in the environment for long periods

Front 327

General characteristics of neisseria

Back 327

1. Colonize the mucosal surfaces of mammals

2. Of the man species, 2 (N. meningitidis and N. gonorrhoeae ) are exclusive pathogens of humans

3. Gram-negative, non motile cocci, usually associated in pairs (diplocooci)

4. Very susceptible to exposure to the environment, thus require close or intimate contact for transmission

5. 2 kidney bean shaped cocci facing each other, appears like a “doughnut”

6. Gram negative pyrogen – cause disease by hyper-reactivity of our immune response to LPS
a. LYN: LPS causes endotoxic shock because of the cytokine cascade
b. Gram positive pyrogens however cause disease by elaboration of extracellular products/toxins

Front 328

The clap

Back 328

1. contracted by acquiring Neiseria infected PMNs, not organism

2. disable processes of PMNs

Front 329

N. meningitidis and N. gonorrhoeae

Back 329

1. pathogenic ones; humans are the only host

2. Others are members of the normal flora --> so they only become pathogens under rare circumstances

Front 330

CTA Test (Cystine Trypticase Agar Test)

Back 330

1. Neisseria spp are differentiated by their ability or lack of ability to utilize specific sugars

2. CystineTrypticaseAgar (CTA) is the basal medium most commonly used to determine carbohydrate utilization by the Neisseria. To this basal medium is added a single carbohydrate source such as glucose, sucrose, maltose, lactose.

3. After inoculation with the suspected organism and incubation for at least 24 hours, the medium is examined for a change in colour from to RED to YELLOW. This colour change is caused by the accumulation of acid which is detected by the pH indicator, phenol red which is included in the basal medium

Front 331

N. gonorrhoeae

Back 331

only ferments glucose

Front 332

N. meningitidis

Back 332

1. ferments both glucose and maltose

** N. MeninGitidis = Maltose and Glucose. N. Gonorrhoeae = Glucose

Front 333

N. flavescens

Back 333

ferments none of them

Front 334

N. lactamica

Back 334

ferments glucose, maltose, and lactose

Front 335

N. sicca

Back 335

ferments glucose, maltose, and sucrose

Front 336

N. gonorrhoeae (aka Gonococcus) Disease

Back 336

1. get infected anywhere just use your imagination,” but 2 main routes

2. Oropharyngeal Infection

3. Anal/Genital Infection

4. Gonococcal Disease of the Infant

Front 337

N. gonorrhoeae - oropharyngeal infections

Back 337

1. pharyngitis = individual with sore throat- remains highly infectious

2. Without treatment – can be linked to systemic spread
i. But in most cases it is self limiting

3. Potential results of systemic spread:
a. Arthritis,
b. Endocarditis,
c. and in rare cases Meningitis

Front 338

N. gonorrhoeae - Anal/Genital Infection

Back 338

1. Local irritation and discharge

2. Male – often symptomatic with painful urination and purulent urethral discharge
i. “Knows for damn sure that he has it”

3. Female – may be asymptomatic and remain infectious, organism can spread systemically
i. Ectopic pregnancy – can be caused by N. gonorrhoeae or Chlamydia
• This results from gonococcal-mediated Pelvic Inflammatory Disease- infection of the uterus (endometritis), fallopian tubes (salpingitis) and/or ovaries (oophoritis)

Front 339

Gonococcal Disease of the Infant

Back 339

1. may contract conjunctivitis during vaginal delivery from an infected mother

2. Known as opthalmia nenoatrum

3. Causes conjunctivitis and may end up in blindness

4. Sulfur Nitrate or Erythromycin Eye Drops – used to prophylactically treat against either a gonococcal or Chlamydia infection contracted during delivery
i. NT Note: called Ophthalmia neonatorum – this eye infection can damage the cornea and result in blindness
ii. Up to 50% of patients infected with N. gonorrhoeae are concurrently infected with Chlamydia

Front 340

Neisseria Spp. Characteristics

Back 340

1. Do not elaborate extracellular products that contribute to pathogenesis

2. An IgAse is produced that has limited immunological significance

3. Pathogenesis is primarily mediated by outer membrane components

4. N. gonorrhoeae does not possess a capsule
- A major detriment to developing a vaccine

5. Pili – mediate attachment to non-ciliated epithelial cells

6. Blebs (Slide 12) – outer membrane fragments that soak up soluble antibodies

Front 341

IgAse

Back 341

1. cleaves soluble IgA

2. Only found in pathogenic Neisseria (ie. N. gonorrhoeae and N. meningitidis)

3. Has limited immunological significance

Front 342

Outer membrane Protein Porins

Back 342

1. Proteins I, II and III Tetramer

2. Protein I – mediates invasion

3. Protein II – strengthens attachment

4. Protein III – maintains the structural integrity of the channel

Front 343

Pili

Back 343

1. mediate attachment to non-ciliated epithelial cells

2. are analogous to M protein of Streptococcus
a. it aids in attachment and comes in many different types

2. they are trying to makea vaccine to the pili; it doesn’t work

3. Thousands of types that mutate rapidly, and are thus not very immunogenic

Front 344

Blebs

Back 344

1. outer membrane fragments that soak up soluble antibodies

2. LOS lipooligosaccharide – the same as LPS but instead contains the O sugar component

3. O sugar = shorter length (5-6 sugars) than the P sugar (polysaccharide; 50-60 sugars) of LPS

4. LOS is responsible for inducing the vigorous inflammatory response, just as LPS does

5. In the outer membrane

Front 345

N. gonorrhoeae Infectious Process

Back 345

1. Attachment

2. Firm Binding

3. Invasion

4. Extrusion of neighboring ciliated epithelial cells – mediated by LOS, (within 3 days)

Front 346

N. gonorrhoeae Attachment

Back 346

1. Pili mediate attachment to non-ciliated columnar epithelial cells

2. It can live outside the cell or can go inside the cell

3. It’s a facultative intracellular organism  it doesn’t have to live inside the cell

Front 347

N. gonorrhoeae Firm Binding

Back 347

Protein II enables subsequent stronger binding to epithelial cells

Front 348

N. gonorrhoeae Invasion

Back 348

1. this is determined by the type of Protein I (A or B)

2. The organism carries 2 alleles
a. PIA or PIB

3. Protein IA – causes “Parasite Directed Endocytosis”

4. Degranulation/Lysosomal Fusion is inhibited within the PMN

5. No invasion if Protein IB is expressed

Front 349

Protein IA

Back 349

1. causes “Parasite Directed Endocytosis” –it initiates endocytosis of the N. gonorrhoeae in a non-phagocytic cell, the non-ciliated epithelial cell (within 1 day)

2. It turns a nonphagocytic cell into a phagocytic one

3. Once inside the cell, it takes sialic acid and coats itself in it
i. Sialic acid turns off the alternative pathway of complement degradation
ii. In the blood stream the organisms can add sialic acid to the penultimate LOS sugar and evade complement killing

4. If carrying the P1A allele it travels through the epithelial cell to exit via the basement membrane and enter the blood stream
i. or if in a PMN, inhibit degranulation and become facultative intracellular parasites. The PMNs can become vehicles for subsequent re-infection.

Front 350

N. gonorrhoeae - Extrusion of neighboring ciliated epithelial cells

Back 350

1. mediated by LOS, (within 3 days)

2. Damaged/Compromised ciliary elevator in the fallopian tube => no longer transmits egg/sperm

3. High risk for Ectopic Pregnancy and Sterility --> because of development of Pelvic Inflammatory Disease
a. A non-ciliated cell takes in gonococcus
i. Signals are sent out, possibly through the blood stream
ii. Which causes extrusion of the ciliated epithelial cell in the fallopian tube

Front 351

No Effective Vaccine for N. gonorrhoeae

Back 351

1. No capsule and no suitable animal model has been developed because it’s exclusively an human pathogen

2. Pili have high antigenic variability

3. Protein I has 18 different serotypes

4. Protein III is closely aligned with Protein I and therefore induces “Blocking Antibodies”

5. Appears to be no natural immunity to N. Gonorrhoeae - it’s the gift that keeps on giving
i. Condoms are best measure in preventing transmission

Front 352

Blocking antibodies

Back 352

1. bind to Protein III in a non-lethal way in which they also prevent other antibodies from binding; these antibodies also cannot bind or activate complement

2. Protein 3 is common with all the gonococci

3. So it causes the induction of Abs to protein 3, which shield protein 1 from antibodies

Front 353

Diagnosing N. gonorrhoeae infection

Back 353

1. Gram Stain – visualize Gram negative, “doughnut” diplococci

2. Culture on Thayer Martin VCN Agar followed by CTA analysis

3. Oxidase test positive

Front 354

N. gonorrhoeae gram stain

Back 354

1. Blood, CSF, Penile Exudate

2. May have difficulty with contamination by normal flora

3. confirm with sugar

Front 355

Culture on Thayer Martin VCN Agar

Back 355

1. Female UGT, rectum, oropharynx- cannot do gram stain because there are too many other organisms

2. A chocolate agar – blood plate that has been heated, lysing the RBCs of the media

3. This plate also contains antibiotics to kill competing bacteria
a. V: Vancomysin – kills Gram +
b. C: Colistin – kills Gram –
c. N: Nystatin – kills fungi

4. Then do CTA to determine N. spp

Front 356

Oxidase test positive

Back 356

1. All members of the genus are oxidase positive. Colonies turn black when flooded with oxidase reagent (1% dimethyl-tetramethyl-phenylenediamine)

2. Neisseria grow best in an atmosphere of 5-10% Co2 as that provided by a candle jar

Front 357

Treating N. gonorrhoeae infection

Back 357

1. Usually self limiting but must prevent it from disseminating (“grin and bear it”)

2. Ocular Therapy – Sulfur nitrate or Erythromycin

3. Ceftriaxone = current therapy of choice, a third generation cephalosporin (CMMRS p.68)
i. Resistance to Beta lactams, tetracycline, and fluoroquinolones has risen since Vietnam War
ii. N. gonorrhoeae now produces Beta lactamase

Front 358

N. meningitidis (aka Meningococcus) Characteristics

Back 358

1. High mortality (can kill in 24 hours) – very few microbes are more lethal
i. ~100% mortality if untreated, <15% if treated with appropriate antibiotics
ii. Death often occurs within in a few hours

2. Cerebral meningitis is most serious consequence
i. You get explosive epidemics of the disease
ii. Epidemics occur most frequently in circumstances in which large numbers of individuals, especially from different geographic regions, are brought together under crowded and stressful conditions

3. Same media growth characteristics and gram stain characteristics as gonococcus

4. Also attaches and colonizes non-ciliated columnar epithelial cells, causes purulent infections, and induces parasite-mediated endocytosis by similar mechanisms, also produces blebs (like gonococcus)

5. Produces endotoxin

6. Distinguished by CTA Test – sugar fermentation
i. Most distinguishing feature is its carbohydrate capsule – important in developing protective immunity – and different carbohydrate fermentation pattern

Front 359

Meningitis (meningococcemia in meninges)

Back 359

1. Associated with acute meningococcemia

2. Transmission via Close Contact
i. Boot camp – crowded/stressful conditions in which many individuals from different geographical regions are brought together who may harbor different strains of N. meningitidis
ii. The carrier rate of N. meningitidis goes from 5% in the generation population to about 40% in boot camp, this is alarming because carrier’s only have antibodies made against the particular strain they carry (p65 CMMRS).

3. Spread by respiratory droplets
i. Penetration into the bloodstream leads to disseminated disease and subsequent CSF penetration

4. Complement Deficiencies, especially Membrane Attack Complex Deficiencies (ie. C5-C9) – are particularly susceptible to N. meningitidis infection
i. NT Note: Remember Neisseria infection are intracellular => using this mechanism to kill infected cells is critical

Front 360

Epidemic Meningitis

Back 360

1. Groups B and C are most often found in the US

2. Group A major pathogen in African

3. Group B major pathogen in US

4. Epidemic disease – most common in young adults (N. meningitidis)

5. Endemic disease – most common in children (H. influenzae)

6. congenital complement deficiencies- more prone to meningitis

Front 361

Waterhouse Friderichson Syndrome

Back 361

1. (meningococcemia in skin)

2. Fulminant meningococcemia

3. It begins abruptly with sudden high fever, chills, myalgias, weakness, nausea, vomiting, and headache. Apprehension, restlessness, and frequently, delirium occur within the next fewhours.

4. Widespread purpuric and ecchymotic skin lesions appear suddenly. Typically, no signs of meningitis are present.

5. Pulmonary insufficiency develops within a few hours, and many patients die within 24 hours of being hospitalized despite appropriate antibiotic therapy and intensive care

6. Caused by blood borne dissemination of N. meningitidis, in 5-15% of infected patients

7. Demonstrates diffuse intravascular clotting visible on the skin as “purpura fulminans”

8. Meningicoccus merges in the skin

Front 362

Classification of N. meningitidis

Back 362

1. There are many different capsules that N. meningitidis can express

2. Provide the basis for serogrouping these organisms

3. A B, C, H, I, K,L, X-Z, 29E, W135 : but “just know the main ones”

4. (CMMRS) Serotypes A, B, C – most often cause Meningitis

5. Capsule-mediated meningococcal immunity – is group/type specific for all groups but Group B

6. Vaccines to all groups except B are based on capsules, Group B vaccine is based on porin membrane protein- shown to be effective

Front 363

Group B Meningococcus

Back 363

1. antigenic expression so closely resembles human protein expression that antibodies cannot be made against it

2. Is a sialic acid polymer: like self that generates little immunity

Front 364

Epidemiololgy

Back 364

1. Occurs sporadically in epidemics

2. Epidemic disease is most common amongst young adults particularly those sequestered in crowded conditions

3. Individuals with congenital complement deficiencies

Front 365

Pathogenesis of Meningococcal Disease

Back 365

1. Meningococcus are spread by respiratory droplets.

2. The human nasopharynx is the ecological niche of the meningococcus where the organisms attach to the microvilli of non-ciliated columnar epithelia.

3. Attachment is mediated by pili and class 5 (gonococcal P2) outer membrane proteins.

4. Parasite-directed endocytosis of the mucosal cells occur as with the gonococcus in which class 2 and 3 proteins (gonococcal P1) translocate into the eucaryotic cell membrane.

5. The organisms are then translocated to the basement membrane and released into the blood stream. Once in the bloodstream, the meningococcus multiplies rapidly reaching blood titers that are among the highest known for any bacterium.

6. The entry of meningococci into the bloodstream can lead to the development of purpura fulminans caused by diffuse intravascular clotting (DIC) with skin manisfestations (petechiaand ecchymoses), (Waterhouse-Friderichsen syndrome).

7. Organisms then pass into the CSF then to the meninges withprogression tomeningitis, shock and death. This is caused in major part by the action of endotoxin mediated by tumour necrosis factor and interleukin-1.

8. Like the gonococcus, the meningococci release "blebs" of outer membrane which are very rich in LOS. This continuous release of endotoxin is most likely responsible for the sever endotoxic reaction observed in meningococcemi

Front 366

Haemophilus genus

Back 366

1. One of the major causes of meningitis

2. Morphology: Gram negative, pleomorphic coccobacilli
i. Shape can vary between cocci, bacillus, coccobacillus, and stranded (fungus-like)
a. The organism’s environment dictates its shape

Front 367

Haemophilus Classification/Speciations

Back 367

1. Haemophilus can be speciated by whether or not it requires X Factor (Hemin aka Heme, Hemoglobin) and/or V Factor (NAD), and whether it is hemolytic or non-hemolytic

Front 368

H. influenzae

Back 368

1. Requires the presence of both X Factor and V Factor for growth

2. Like most Haemophilus species, it is non-hemolytic

3. A throat swab is taken from a child you believe to have H. influenzae. You plate the swab on blood agar and find no bacterial growth the next day. So what happened here? Well, H. flu is non-hemolytic so it cannot access the heme inside intact RBCs, and therefore cannot grow. You must use a chocolate agar plate, which contains lysed RBCs, to culture for H. flu.

Front 369

Major Haemophilus Species

Back 369

1. Haemophilus influenzae

2. H. aegypticus, sometimes called H. influenzae biotype III

3. H. ducreyi

4. H. parainfluenzae

Front 370

Haemophilus influenzae

Back 370

1. can be divided into two groups
a. Typeable
b. Non-typeable

2. Transmission is through aerosol (“floating”) bacteria, by coughing for example

Front 371

Haemophilus influenzae Typeable

Back 371

1. Encapsulated

2. 6 types, labeled Types A – F, based on the capsule composition

3. Type b
• most important, involved in 95-98% of all diseases caused by H. flu
• the major cause of meningitis in infants (2 months - 3 years)
• currently, the only type to have a vaccine available against it. All encapsulated H. flu types could have a vaccine, but only type b is dangerous enough to warrant it.

Front 372

Haemophilus influenzae Non-typeable

Back 372

i. Non-encapsulated
• Can be responsible for bronchitis, otitis media, pneumonia, puerpural sepsis, acute sinusitis, arthritis, and cellulitis

Front 373

H. aegypticus

Back 373

1. Diseases:
a. pink eye
i. highly contagious; most of us have had this
b. Brazilian purpuric fever

Front 374

H. ducreyi

Back 374

1. A STD that causes an ulcer

2. Infects skin, usually the penis, causing an ulcer known as a chancroid. Chancroid can be distinguished from Treponema pallidum (syphilis) by the following:
a. Can actually form a fistula through the penis or other tissue
b. Disease was rarely studied until emergence of HIV
i. Sores caused by H. ducreyi facilitate HIV transmission

3. Can cause bobos – swelling of the lymph nodes

4. Transmission:
a. Sexual intercourse
b. Any contact with the lesion – skin to skin
c. Can be asymptomatic in women, although they remain infectious

Front 375

H. parainfluenzae

Back 375

1. Can cause diseases similar to H. flu

2. Is less pathogenic or virulent than H. flu

Front 376

H. influenzae in more detail

Back 376

1. 2 types [52]:
a. capsulated
b. non-encapsulated

2. Virulence factors – Capsule, outer membrane proteins, and lipo-oligosaccharide

3. Disease process is similar to N. meningitidis

Front 377

H. influenzae - Capsule polysaccharide

Back 377

1. Anti-phagocytic

2. Main antigenic determinant – the epitope of an antigen (Wiki)
i. Antibodies to capsule promote opsonization (repeated several times throughout lecture)

3. Confers type specificity:
i. 6 serotypes: A-F
ii. The nomenclature is similar to Strep pneumonia (LYN)
• Conceptually, “type specificity” is the same thing as “group specificity”
iii. Virtually all strains associated with invasive disease belong to Type b
• Hib – refers to “Haemophilus influenzae Type b”
• Think type b = bad!

Front 378

H. influenzae Type b capsule

Back 378

1. Unique in that it contains pentose sugars, ribose and ribitol phosphate
- other serotypes contain hexoses or hexosamines (LYN)

2. the type b capsule is referred to as PRP (polyribose phosphate)

3. PRP vaccine is to Hib

Front 379

H. influenzae - Outer Membrane Proteins

Back 379

1. Analogous to proteins found on Neisseria gonorrhoeae and meningitidis

2. Specific OMPs:
i. PII - believed to facilitate attachment
ii. PIII
iii. PI
• Can facilitate parasite directed endocytosis
• Has an a and b variant
• PIa associated with invasive disease

Front 380

H. influenzae - Lipo-oligosaccharides (LOS)

Back 380

1. Similar to Neisseria LOS

2. A major virulence factor for H. flu due to human reaction to endotoxin
i. Main virulence factor (LYN)

3. LOS can induce “ciliary stasis” with concomitant sloughing off of bronchial epithelial cells
i. analogous to the actions of N. gonorrhea in the fallopian tube

4. Similar to LPS of E.coli but with a shorter carbohydrate chain

Front 381

Disease process of H. influenczae

Back 381

1. Transmission: H. flu particles are inhaled in air

2. Adherence: to nasal mucosa

3. Invasion: Particularly strains possessing PIa allele.
a. Encapsulated and non-encapsulated
i. In upper respiratory tract, submucosal invasion causes rhinnorhea. In lower respiratory tract it causes bronchitis
ii. The capsule, if antibodies to it are not present, prevents phagocytosis and allows invasion to blood stream

4. Epiglottitis

Front 382

Epiglottitis

Back 382

1. Principally in children ages 3 to 7

2. H. flu invades the larynx: the epiglottis, the artenoid fold and the posterior wall of the hypolarynx

3. Results in epiglottitis
i. Cellulitis of these structures
ii. Swelling can cause a constriction of the airway that can require surgical intervention
iii. Antibiotics therapy is effective

Front 383

H. Influenzae disease process continued

Back 383

1. H. flu in blood can gain access to CSF then to meninges.

2. Again, most common cause of meningitis in infants 2 months to 3 years

3. Meningitis progression is similar compared to meningococcal disease, except that H. flu meningitis leads to further neurological damage in 1 in 10 infants.
a. Most commonly causes mental retardation. Also blindness, deafness, obstructive hydrocephalus

4. Without prompt antimicrobial therapy, mortality approaches 100% [59]

5. Rifampin can be used to prevent infection in immune and non-immune household members who have been exposed to a child with Hib meningitis
a. Chemoprophylaxis is about 95% effective in eliminating the carrier state

Front 384

H. influenzae vaccine

Back 384

1. To induce immunological memory, we conjugate the carbohydrate Hib PolyRibosePhosphate subunits to small synthetic peptides

2. 3 conjugate vaccines are now available
a. PRP-D vaccine
b. HbOC vaccine
c. PRP-OMP vaccine

Front 385

PRP-D vaccine

Back 385

i. Hb PRP capsular material conjugated to diphtheria toxoid

ii. Provides immunity to both diphtheria and Hib

Front 386

HbOC vaccine

Back 386

i. PRP conjugated to CRM197 (a non-toxic fragment of the diphtheria toxin)

ii. Does not protect against diphtheria

Front 387

PRP-OMP vaccine

Back 387

1. PRP is conjugated to the outer membrane protein of Neisseria meningitidis

Front 388

Incidence of H. flu meningitis

Back 388

1. is inversely related to the bactericidal activity of serum to PRP.

2. The highest incidence of cases falls within the time frame in which trans-placental immunity from the mother is diminished (after the 1st 6 months) and before natural immunity is developed by the infant on its own.

3. The goal of vaccinations is to shorten or eliminate this time of susceptibility.

4. Other pathogens that have a capsule as an important virulence factor would look very similar to H. flu if graphed like this; Staph aureus, Strep pneumonia, Neisseria meningitides are examples.

Front 389

H. flu - Clinical identification

Back 389

1. If meningitis is suspected, CSF analysis is recommended

2. Plating

3. Other methods

Front 390

CSF analysis

Back 390

a. Gram stain the CSF and look for bacteria

b. H. flu will be Gram – and pleomorphic

Front 391

H. flu - Plating

Back 391

1. Can be plated on chocolate agar to grow [66]

2. Haemophilus speciation utilizes Factor X and V

3. Satellite test

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Haemophilus speciation utilizes Factor X and V

Back 392

1. Streak a minimal agar plate

2. Apply 3 pieces of paper
• One contains X factor, one contains V factor, and one contains both X and V factor

3. This allows you to determine which factors the organism requires to grow, and therefore allows you to determine the Haemophilus species.

Front 393

Satellite test

Back 393

1. An unheated blood plate is used instead of chocolate agar

2. S. Aureus is plated in a thin streak with H. flu plated around it

3. S. Aureus hemolyses the RBC’s, releasing Factors X and V required by H. flu

4. Colonies of H. flu will be observed growing around the lysed area. This is known as the satellite effect.

Front 394

H. Flu clincial identification other methods

Back 394

1. Serotyping by:
i. Agglutination
ii. Precipitation
iii. Quellung Reaction
iv. Immunoflourescence

2. Mass spectrometry
i. Test developed by Dr. Johnston’s students that a company has adopted
ii. Can distinguish Haemophilus and Neisseria species in 15 minutes

Front 395

Bordetella

Back 395

1. a non-pyogenic organism

2. causes disease via the production of toxins,

3. does not invade,

4. is the etiological agent of whooping cough

5. Spread by aerosols or direct contact

Front 396

Bordetella Spp.

Back 396

1. Bordetella pertussis (etiological agent of pertussis, aka whooping cough)

2. Bordetella parapertussis (milder form of pertussis)

3. Bordetella bronchiseptica (causes ‘kennel cough’ in dogs, the vaccines for this and pertussis are very similar)

Front 397

Bordatella Morphology

Back 397

1. Organisms are minute,

2. gram negative,

3. non-sporulating coccobaccilli

4. can be difficult to distinguish from Haemophilus on gram stains

Front 398

Bordatella disease process

Back 398

1. organisms enter the trachea and bronchi by inhalation and attach to the cilia of epithelial cells of the large airways

2. They colonize the ciliated respiratory epithelium and produce toxins which cause the disease
a. In some cases B. pertussis can invade alveolar macrophages in the region, but they don’t migrate anywhere else. This can lead to a carrier state
b. It is a totally localized infection and any disease is a result of the production of toxins at that site and their subsequent dissemination – essentially a non-invasive organism

Front 399

Bordetella pertussis

Back 399

1. causes pertussis

Front 400

Pertussis

Back 400

1. Acute disease of the respiratory tract

2. Characterized by progressive, repetitive, paroxysmal coughing

3. The hallmark of the disease is an inspiratory whoop, hence the common name, whooping cough
a. This coughing will go on for weeks and by the time the whooping begins the organism is essentially gone and there is no effective antibiotic treatment, the only option is supportive care
b. It in an inspiratory cough

Front 401

Pertussis in the U.S

Back 401

1. there were around 200,000 cases/yr in the late 1940’s,

2. as the vaccine became widely available the numbers dropped dramatically,

3. however, for various reasons (such as incomplete vaccination coverage) there has been an increase since 1980

Front 402

Stages of Pertussis

Back 402

1. Incubation stage (7-10 days)

2. Catarrhal, prodromal or pre-paroxysmal stage (1-2 weeks)

3. Paroxysmal or spasmodic stage (may last several weeks)

4. Convalescent stage (3-4 weeks or longer)

Front 403

Incubation stage

Back 403

1. 7 -10 days

2. Infection and attachment of organisms to ciliated epithelial cells

3. Symptoms resemble the common cold – slight cough, runny nose, low grade fever
i. You think that you just have a cold

4. Slightly infectious

5. Responds to antibiotic treatment

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Catarrhal, prodromal or pre-paroxysmal stage

Back 404

1. 1-2 weeks

2. Organisms multiply rapidly

3. Coughing, but not the whoop, and more severe cold-like symptoms
i. You are coughing up organism

4. Highly infectious stage

5. Can be treated at this stage with antibiotic therapy

6. Epithelium intact but submucosa becomes inflamed, peribronchial nodes enlarge

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Paroxysmal or spasmodic stage

Back 405

1. may last several weeks)

2. Organisms have begun to die off, toxins have been secreted

3. Uncontrollable coughing with characteristic whoop

4. Hypoglycemia, marked leukocytosis

5. Not responsive to antibiotic therapy

6. Greatest danger to infants is the inability to clear secretions and maintain nutrition – the cough may be so persistent that it prohibits the infant from being able to take in food

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Convalescent stage

Back 406

1. (3-4 weeks or longer)

2. Diminished cough, hypoglycemic state and lymphocyte count returns to normal
i. You actually make very effective antibodies

3. Severe consequences may result
i. Secondary bronchopneumonia due to the fact that the respiratory cilia have been compromised resulting in increased susceptibility to other infections
ii. Acute encephalopathy characterized by convulsions and brain damage – it has been suggested that this is a result of the action of toxins on the Islets of Langerhans, inducing the hypoglycemic state

4. Protective immunity is generated via antibody response

Front 407

Bacterial levels during stages of pertussis

Back 407

amount of bacteria rises during the incubation stage, plateaus during catarrhal, and drops off over the final two stages

Front 408

B. Pertussis major virulence factors

Back 408

1. Filamentous hemagglutinin (Fha)

2. Pertussis toxin

3. Adenylate cyclase

4. Dermonecrotic toxin

5. Tracheal cytotoxin

Front 409

Filamentous hemagglutinin (Fha)

Back 409

1. Molecule that binds to cilia to induce ciliary stasis, possibly leading to secondary infections (H. influenzae, S. pneumoniae)
i. This compromises your ability to clear the bacterium and other organisms --> leading to possible secondary infection

2. Also can bind CR3 receptor on macrophages to help induce phagocytosis and the carrier state. (When inside macrophages, this bug can retard oxidative burst triggering)

Front 410

Pertussis toxin

Back 410

1. Main virulence factor

2. A-B toxin composed of 6 units (one enzymatic subunit and 5 binding subunits)
i. Binds to ciliated respiratory epi cells

3. A is the active/enzymatic component, and B is the binding component
i. Binding leads to internalization and the end result is an increase in cAMP (a common result for many toxins)

Front 411

Increased cAMP is what is causing the disease process – results in activation of protein kinases which cause:

Back 411

1. Histamine sensitizing effect – high susceptibility to anaphylaxis

2. Islets of Langerhans activating effect – increased insulin synthesis, hypoglycemia, and possible neurological complications
a. 10% infants may develop seizures
b. 0.1% develop encephalopathy

3. Inhibition of phagocytic activity of macrophages and killing function of PMNs – may promote the carrier state

4. Suppression of antibody synthesis – may contribute to predisposition to developing secondary pulmonary infections

Front 412

Adenylate cyclase

Back 412

1. Not only does the organism stimulate host adenylate cyclase via the pertussis toxin, but it produces its own adenylate cyclase

2. Enters host cells and interacts with calmodulin and causes a large increase in cAMP independent of the host’s normal cAMP feedback mechanisms
i. Leads to the same results of increased cAMP as listed above
ii. Can get 1000 X more cAMP

Front 413

Dermonecrotic toxin

Back 413

1. Involved in destruction of epithelial layer

2. Local necrosis allows for the establishment of secondary infections

3. Causes skin lesions

Front 414

Tracheal cytotoxin

Back 414

1. It is released into extracellular fluid

2. Peptidoglycan fragment

3. Causes extrusion of ciliated cells (like Neisseria in the fallopian tubes) and interferes with DNA synthesis

4. Primary cause of cough

Front 415

B. Pertussis secondary infections

Back 415

1. can result from direct colonization of the destroyed tissue or from the lack of cilia allowing other bacteria to enter the lungs

2. Possible death – many times an infant will succumb due to the constant whooping leading to an inability to actually take nourishment (essentially starving to death)

3. Possible carrier state – the organisms that hang around, particularly in adults, can become potential agents for transmitting the disease to children

Front 416

B. Pertussis Diagnosis

Back 416

1. A swab must be taken in the first few weeks and added to Bordet-Genou or Regan-Lowe medium to grow (due to the course of disease, Bordetella organisms will only be found during the first ~2 weeks of disease)

2. You can also take a swab and do direct fluorescent antibody tests on secretions

3. Commonly today the lab will run direct PCR tests

Front 417

B. Pertussis Treatment

Back 417

1. Individuals with unrecognized infections (lack of a whoop) can harbor B. pertussis and act as reservoirs or carriers and may pass the disease to children who have not been vaccinated

2. Tx. of infection is possible using erythromycin, but due to the etiology of the disease (appears as a cold until “whoop” appears), vaccine use is recommended

Front 418

B. Pertussis Vaccine

Back 418

1. Original vaccine was heat killed organisms in suspension with purified diphtheria and tetanus toxoids (original DTP vaccine)
i. This was an effective vaccine, but there was some reaction to it

2. New research showed that what was really needed was an antibody to the pertussis toxin – so toxoid was used to generate an appropriate antibody response

3. A new acellular vaccine was made in Japan containing toxoid and Fha to prevent attachment

4. Now what is used is the diphtheria-tetanus-pertussis vaccine

Front 419

new accellular vaccine

Back 419

1. containing toxoid and Fha to prevent attachment

2. With this vaccine however, there were increased neurological complications
a. The portion of Fha that binds to CR3 is thought to mimic a protein on endothelial cells that binds CR3 when PMNs prepare to exit a blood vessel
b. Antibodies against that portion of Fha might bind to endothelial cells, thus stimulating leakage from capillaries and subsequent neurological complications

3. Fha is no longer included in pertussis vaccines

Front 420

diphtheria-tetanus-pertussis vaccine

Back 420

1. uses acellular pertussis and is known as DTaP

2. It is given in 5 doses at 2, 4, 6, 12-18 months, and 4-6 years

3. Recently a new vaccine also adds protection against H. influenzae, called DTaPHib

Front 421

Meningococcal Vaccines

Back 421

1. MPSV4

2. MCV4 (Menactra

3. Group B Vaccine

Front 422

MPSV4

Back 422

1. Meningococcal polysaccharide vaccine that protects against 4 major serogroups of meningococci – A, C, Y, and W-135

a. These 4 serogroups are the major ones (most virulent) that actually cause disease

b. B subgroup is not listed because it looks like self

Front 423

MCV4 (Menactra)

Back 423

1. Conjugate Meningococcal Vaccines

2. licensed in 2005

3. Contains the same 4 serogroups as MPSV4, but each are conjugated (covalently bound) to diphtheria toxoid
a. Diphtheria toxoid (or a portion of it) serves as a carrier of the conjugate vaccine

4. MCV4 gives a better, longer-lasting protection than the polysaccharide vaccine

5. This is most likely what you would have received if you took the meningococcal vaccine

6. Not yet licensed for children less than 2 years old, but they are working on it

Front 424

Group B Vaccine

Back 424

1. Vaccine protects against serogroup B (that has the sialic acid capsule) which causes about one third of all the meningococcus cases in the U.S.

2. Not yet approved for licensure

3. PRP-OMP vaccine

Front 425

PRP-OMP vaccine

Back 425

1. PRP protects against Haemophilus

2. OMP (outer membrane protein) is the major protein (protein 1) of the Group B meningococcus

3. This vaccine results in partial immune response to Group B

Front 426

Pneumococcal Vaccines

Back 426

1. PCV7 (Prevnar)

2. Pneumococcal polysaccharide vaccine

3. Work is still being done on PSPA, which is a common protein shared by all pneumococci

Front 427

Pneumococcal polysaccharide vaccine

Back 427

1. Old formulation contained purified capsular material from 14 types of pneumococcal bacteria

2. New formulation contains purified capsular material from 23 types – known as PPV23 or simply PPV
a. PPV licensed for adults and persons over 2 years of age with certain risk factors

Front 428

PCV7 (Prevnar)

Back 428

1. Vaccine includes purified capsular polysaccharide of 7 capsular types conjugated to diphtheria toxin

2. Pediatric vaccine – prevents pneumococcal disease in infants and young children from age 6 weeks to the 5th birthday

Front 429

Anaerobes

Back 429

1. Very large group of organisms, many of which are members of the normal flora

2. They can cause disease because they require an environment lacking oxygen

3. Example: trauma
i. Oxygen tension of region decreases dramatically, making it anoxic
ii. Allows for organisms to multiply and cause disease
iii. Thus, most of these are called opportunistic pathogens

Front 430

Bacterial requirements for growth

Back 430

1. Oxygen (or absence) – determining factor for anaerobic bacteria

2. Energy

3. Nutrients

4. Optimal temperature

5. Optimal pH

Front 431

5 types of bacteria based upon oxygen requirements

Back 431

1. Obligate aerobes – require oxygen to live

2. Microaerophiles – require less than atmospheric levels of oxygen to grow, and they prefer environments containing 10% or more carbon dioxide
a. Classic example: Neisseria
b. You can achieve the proper environment for their growth by initially isolating them and placing them in a candle jar with a lit candle. You then close the lid, burning up all the oxygen and creating an environment consisting of 10% carbon dioxide.

3. Obligate anaerobes – require an anaerobic environment; oxygen is toxic to them

4. Facultative anaerobes – can use oxygen metabolically, but they can also grow in an anaerobic environment
a. Example: many of the Streps

5. Aerotolerant anaerobes – can grow in anaerobic or aerobic environment, but they do not use oxygen metabolically

Front 432

Test tube example

Back 432

1. Obligate aerobic bacteria – gather at the top of the test tube in order to absorb the maximal amount of oxygen

2. Obligate anaerobic bacteria – gather at the bottom to avoid oxygen

3. Facultative bacteria – gather mostly at the top, since aerobic respiration is the most beneficial one; but as a lack of oxygen does no hurt them, they can be found throughout the growth medium in the test tube

4. Microaerophiles – gather at the upper part of the test tube but not at the top; require oxygen but at a lower concentration

5. Aerotolerant bacteria – are not affected at all by oxygen and they are evenly spread throughout the test tube

Front 433

Bacterial growth and metabolism

Back 433

1. During this process, oxygen reduction byproducts are generated within microorganisms and tend to accumulate
a. Byproducts include superoxide anion, hydroxyl radical, hydroxyl ion, hydrogen peroxide, and hypochlorite ion

2. These byproducts/radicals can prove toxic to enzymes and cell structures and must be neutralized to prevent cell death

3. In aerobic or facultative bacteria, these toxic products accumulate as a result of oxygen metabolism. However, they have detoxifying pathways consisting of enzymes such as superoxide dismutase, catalase, peroxidase, or any combination of them. Thus, they can detoxify the toxic products, making them nontoxic (13)

4. In anaerobic bacteria, the detoxifying pathways/enzymes do not exist, resulting in the accumulation of toxic products and ultimately bacterial cell death

Front 434

Problems in identification of anaerobic infections

Back 434

1. They are often derived from the normal flora. One must be confident that they have not isolated a contaminant

2. If air gets into the sample during the sampling process or transportation to the clinical laboratory, then the organism may not be isolatable

3. Slow growth of the organism (due to inefficiency of fermentation) means isolation takes several days or longer

Front 435

Specimen collection

Back 435

1. Main point for us as physicians: take the sample properly and prepare it for transport to the lab (maintain the anaerobic environment)

2. If not done properly, you will receive a lab report a few days later, indicating that there are no bacteria due to the effects of oxygen

3. The BBL Vacutainer Anaerobic Specimen Collector is the only media-free device for anaerobic specimen collection available

Front 436

BBL Vacutainer Anaerobic Specimen Collector

Back 436

1. Swab the specimen

2. Place in the tube

3. Depress the plunger to ensure an anaerobic environment, which is indicated by a color change

4. Send it to the laboratory

5. Once it arrives at the laboratory, it must be placed in a growth chamber (anaerobic jar), which is used for primary isolation of anaerobic bacteria (18)

6. Take sample from tube and place it on plate in the anaerobic jar

7. A pak (Gas-Pak) is opened and water is added to the pouch

8. The interaction of the water with the chemicals (sodium borohydride, sodium bicarbonate, and citric acid) in the Gas-Pak forms hydrogen and carbon dioxide

9. The palladium catalyzes a reaction between the oxygen and the hydrogen gas within the jar, creating water, which shows up as condensation on the inside of the jar

10. The bottom line is to get rid of oxygen and create anaerobic conditions

11. The methylene blue indicator strip changes from the color blue (in the presence of oxygen) to white (anaerobic environment) when the oxygen is converted to water

Front 437

Basic processing of anaerobic clinical specimens

Back 437

1. Collect anaerobic specimen and send to lab

2. In the lab, it is placed in some sort of container consisting of an anaerobic environment in order to isolate
a. Anaerobe jar
b. Roll tube
c. Glove box

3. Anaerobe identification can then occur through one of the following:
a. Colony morphology
b. Gram staining
c. Antibiotic sensitivity patterns
d. Carbohydrate fermentation reactions
e. Biochemical tests
f. Gas chromatography of metabolic products

4. Bottom line: we are the first line of defense because we have to take the sample properly

Front 438

Anaerobes can be divided into 2 types

Back 438

spore formers and non-spore formers

Front 439

Spore formers

Back 439

1. spores germinate in anaerobic environment

2. Gram-positive bacilli

3. Except for Clostridium difficile, most of them are called exogenous pathogens because you have to be infected with a spore from an outside source

Front 440

Non-spore formers

Back 440

1. Gram-positive cocci

2. Gram-positive bacilli

3. Gram-negative bacilli

Front 441

Endogenous infection by anaerobes

Back 441

1. Most anaerobes in the normal flora are non-spore formers from which anaerobic infections often occur (endogenous)

2. Non-spore formers (endogenous anaerobic bacteria) rarely produce exotoxins in contrast to spore-formers; they cause disease not by spores but by the body’s immune response to the pathogen

3. Some anaerobes normally live in the crevices of the skin, in the nose, mouth, throat, intestine, and vagina. Injury to these tissues (i.e., cuts, puncture wounds, or trauma) especially at or adjacent to the mucous membranes decreases the oxygen tension, allows entry of anaerobes into otherwise sterile areas of the body, and is the primary cause of anaerobic infection

4. Anaerobic infections are most likely to be found in persons who are immunosuppressed, those treated recently with broad-spectrum antibiotics, and persons who have a decaying tissue injury, especially if the site is foul-smelling (23)
a. Broad-spectrum antibiotics can kill off the bacteria that maintain the oxygen tension, creating an anaerobic environment suitable for the multiplication of anaerobic bacteria, ultimately leading to disease

5. Most anaerobic infections are polymicrobic (multiple genera)

6. Because they are members of the normal flora, there is rare patient to patient transmission (exception – extremely intimate patient to patient contact)

Front 442

Exogenous infection by anaerobes

Back 442

the introduction of spores into a normally sterile site. Spore-producing anaerobes live in the soil and water, and spores may be introduced via wounds, especially punctures