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99 Cards in this Set

  • Front
  • Back
What is the peptidoglycan layer in bacteria?
repeating disaccharides with 4 aas
gives rigid support and protects agains osmotic pressure
What enzyme catalyzes the formation of crosslinked chains?
transpeptidase aka penicillin binding protein
what is the role of the murein lipoprotein?
extends from the peptidoglycan layer to the outer membrane of the G+s
what is teichoic acid?
The major surface antigen of the cell wall/cell membrane of G+s. Induces TNF and IL1
Break down LPS:
Where is it located?
What are the parts of it.
Located on the outer membrane- G-s
Oligosaccharide unit- O-antigen
Center- core polysaccharide
Interior- Lipid A, disaccharide- endotoxin, induces TNF and IL1; the polysaccharide is the antigen.
What is the function of the plasma membrane?
oxidative and transport enzymes.
What is unique about bacterial ribosomes?
50S and 30S
Erythromycin 50
tetracycline 30
What are the G+ bugs?
Streptococcus- Cat -
Staphylococcus- Cat +

spore producing rods:
(Outer layer of the spore is the exospporium)

plain old rods:
Listeria (only G+ w/ endotoxin)
What is the G- diplococci?
What is the purpose of the following:
periplasm- fluid between cytoplasmic and outer membrane- where B-lactamases are.
capsule- protects from phagocytosis
pilus- mediates adherence of bacteria to cell surface, sex pilus for conjugation
Flagellum- motility- connected by basal body
plasmid- has genes for resistance, enzymes, toxins
Mediates adherence to surfaces, foreign
What is the role of:
Superoxid sdismutase
Catalase-breaks down hydrogen peroxide
peroxidase- same
superoxide dismutase- breaks down the superoxide radical. w/o, not an aerobe.
What bugs have superantigens?
S. Aureus
S. pyogenes

Superantigens bind directly to MHC II and T-cell recptor, activating large numbers of T-cells to stimulate IL 1 and IL 2

S. aureus TSST-1, fever, rash, shock. (enterotoxins- food poisoning)

S. pyogenes- scarlet fever-strain SPE toxin --> toxic shock
What bugs have ADP Ribosylating toxins?
Corynebacterium diptheria
Vibrio cholerae
E. coli
Bordetella pertussis
What is the mechanism of diptheria toxin?
Inactivates elongation factor-2 causing pharyngitis and "pseudomembrane"
What is the mechanism of cholera toxin?
ASP ribosylation of G protein stims cAMP increasing the pumping of CL- and H2O into the gut
rice-water diarrhea
What is the mechanism of the E.Coli toxin?
Heat-labile toxin stimulates adenylate cyclase (like cholera) causing watery diarrhea. It also stimulates guanylate cyclase
What is the mechanism of Pertussis toxin?
Stims adenylate cyclase-> whooping cough, inhibs chemokine receptor causing lymphocytosis.
What is the mechanism of clostridium toxin?
alpha toxin causes gas gangrene, get double zone of hemolysis on blood agar
What is the mechanism of tatanus toxin?
Blocks glycine transmission-> lockjaw
What is the mechanism of botulinum toxin?
Blocks the release of Ach -> CNS paralysis
What is the mechanism of anthrax toxin?
one toxin is an adenylate cyclase
What is the mechanism of shiga toxin?
cleaves host cell rRNA, enhances cytokine release-> HUS
also caused by E. Coli O157:J7
What is the mechanism of S. pyogenes toxin?
streptolysin O is a hemolysin, Ag for ASo in rhumatic fever
What is the mechanism of endotoxin?
Activates macrophages:
IL-1- fever
TNF- Fever, hemorrhagic tissue necrosis
NO- hyoptension

Activates complement (alt path)
C3a- hypotension, edema
C5a- neutrophil, chemtaxis

Activates Hageman factor- Coag cascade-> DIC
What bugs do not gram stain well?
These Rascals May Microscopically Lack Color

Treponema - too thin (darkfield)
Rickettsia- Intracellular
Mycobacteria- acid fast, high lipid content
Mycoplasma- no cell wall
Legionella- intracellular (silver stain)
Chlamydia- intracellular
What is the difference in the Nesseria species in fermentation?
Menigococci- ferment maltose and glucose
Gonococci- ferment glucose
What bacteria produce a pigment?
S. aureus - yellow (gold)
P. Aeruginosa- blue-green
Serratia marcescens- red (maraschino cherries
What bugs use IgA proteases to colonize mucosal surfaces?
S. pneumoniae
Neisseria Meningitidis
N. Gonorrhoeae
H. Influenzae
In bacterial sex, what are the differences between conjugation, transduction and transformation?
conjugation- DNA transferred from 1 to another bacterium, prokaryotic- chromosomal or plasmid (F plasmid)
Transduction- DNA transferred by a virus from 1 cell to another (sperm back)
Transformation- purified DNA taken up by a cell
What is the difference between generalized and specialized transduction?
generalized is any gene (virulent)- bacterial DNA is detroyed, but may be accidently packaged like viral DNA
specialized is a specific gene (temperate) DNA is accidentally repilcated when viral DNA is being replicated.
What is the difference between a virulent and a temperate phage?
virulent- invade and replicate until the bacteria explode.

temperate- DNA is incorporated into bacterial DNA. (prophage) Bacteria with prophage are called lysogenic, they are genetic time bombs.
What is Gram, catalase adn coagulase +?
s. aureus
What is gram and catalase + and coagulase -?
Novobiocin sensitive
s. epidermidis
Novobiocin resistant
S. saprophyticus.
What is Gram +, catalase -, and alpha (green) hemolyitic?
S. pneumoniae- optochin sensitive, bile soluble
Viridans strep- optochin resistant, not bile soluble
What is G+, cat-, and shows Beta (clear) hemolysis?
Group A- s. pyogenes- Bacitracin sensitive
Group B- S. agalactiae- Bacitracin resistant
What is G+, cat-, and shows gamma (no) hemolysis

What type of media do you need to culture H. influenzae?
Chocolate agar with factors V (NAD) and X (hematin)
What type of media do you need to culture N. Gonorrheae?
Thayer-Martin (VCN) media
What type of media do you need to culture B. pertussis?
Bordet-Gengou (potato) agar
What type of media do you need to culture C. diphtheriae?
Tellurite plate, Loffler's medium, blood agar
What type of media do you need to culture M. Tuberculosis?
What type of media do you need to culture lactos-fermeting enterics?
Pink colonies on MacConkey's Agar
What type of media do you need to culture Legionella?
Charcoal yeast extract agar buffered with increased iron and cysteine
What type of media do you need to culture Fungi?
Sabouraud's agar
For what organisms would you use a silver stain?
Fungi, PCP, Legionella
For what organisms would you use a Giemsa's stain?
Borrelia, Plasmodium, trypanosumes, Clamydia
For what organisms would you use a Ziehl-Neelson stain?
acid fast
What gram - cocci is a maltose fermentor?
Nesseria Meningitidis
What G- is a maltose nonfermentor?
Nesseria gonorrhoeae
What are the Gram - coccoid rods? (4)
H. influenzae
B. pertussis
What are some fast G- lactose fermenting rods?
E. coli
What are some slow G- lactose fermenting rods?
What are some non lactose fermenting Ox - G - rods?
What are some non lactose fermenting ox + G- rods?
What bugs are obligate aerobes?
Nagging Pests Must Breathe
Pseudomonas aeruginosa
M. tb
What are the obligate anaerobes?
Clostridium, Bacteroides, Actinomyces.
Foul smelling. hard to culture. Produce gas in tissue
What class of drugs require O2 to enter the cell and kill?
Aminoglycosides- don't work on obligate anaerobes.
What bugs are obligate intracellulars?
Stay inside when its Really Cold.
What bugs are facultative intracellular?
Some Nasty Bugs May Live FacultativeLY
What bugs make spores?

G+ rods
What bacteria are alpha hemolytic?
strep pneumoniae- cat -, optochin sensitive
Viridans strep- cat - and optochin resistant
What bacteria are beta hemolytic
Staph aureus- cat and coag +
Strep pyogenes cat - and biacitracin sensitive
strep agalactiae - cat - and bacitracin resistant
Listeria monocytogenes (tumbling motility, meningitis in newborns, unpasteurized milk)
What is the role of the M protein?
Group A strep, inhibs activation of complement, protects from phagocytosis.
However, plasma cells make Ab against it.
What is the role of Streptolysin O
Streptolysin S
Group A strep enzyme.
O is oxygen labile. Inactivated by O2. Destroys red and white blood cells. allows for B-hemolytic ability. Antigenic

S- also b-hemolytic, not antigenic
What is the role of the pyrogenic exotoxin?
aka erythrogenic toxin
only found in a few strains, but can cause scarlet fever.
What does Group A strep cause?
pyogenic- pharyngitis, cellulitis, impetigo
toxigenic- scarlet fever, toxic shock-syndrome
Immunologic- rheumatic fever, acute glomerulonephritis.
When would you see tea colored urine with strep?
acute post-strep glomerulonephritis- hematuria.
What are the Bs of Group B Strep?
Bacitracin resistant, B-hemolytic, cause pneumonia, meningitis, sepsis mainly in Babies.

neonates- fever, vomiting, poor feeding, and irritability.
What are the 3 most common bugs of meningitis under 3 months old?
Strep B, E. coli, Listeria
What's up with viridans strep?
alpha hemolytic (viridans means green)
dental caries, S. mutans, and endocarditis, S. sanguis (blood). Optochin resistant.
What does S. pneumoniae the most common cause of (4 things)?
Otitis media

Encapsulated, IgA protease
"rusty" sputum
sepsis in sickle cell, and splenectomy
if an alcoholic vomits then develops foul smelling sputum, what organisms are most likely?
Middle age male with acute monoarticular joint pain and bilateral bell's palsy?
lyme disease (ixodes)
What type of immunoglobin is reacting in M. pneumoniae croagglutinins?
What do WBC casts indicate?
what cell is deficient in someone with tetany and candidiasis. With hypocalcemia and immunosuppresion?
DiGeorge- T cell
Thorn prick from a rose, with ulcers along lymph drainage?
Sporothrix schenckii
What causes cauliflower lesions by yeast?
the broad based budding blasto
What would cause redness and swelling of the breast after breast feeding, fluctuant mass?
S. Aureus causing Mastitis
Young child has recurrent lung infections and granulomatous lesions. What is the defect?
Neutrphils lack NADPH oxidase
20 y/o college student presents with lymphadenopathy, fever, hepatospleno. Serum agglutinates in Sheep RBCs?
EBV infection, B Cell is infected
What organism would cause endocarditis 3 wks after getting a heart valve replacement?
S. aureus or S. epidermidis
Why would someone get megacolon and diarrhea after a round of clindamycin?
C. difficile overgrowth
What bug can be grown in 6.5% NaCl?
What is the change made for vancomycin resistance?
d-ala-d-ala is now d-ala-lactate preventing vanco binding
What cancer is associated with S. bovis?
colon cancer
Which strep are paired up?
S. pneumoniae
What is the Quellung reaction?
helps identify pneumococcus- anti serum, the capsule will swell.
Which one is optochin sensitive: viridans or pneumo?
What is the role of Protein A?
bidn the Fc portion of IgG, protects from opsonization
How does coagulase protect the bacteria?
forms fibrin around the bacteria protecting from phagocytosis
What does staph aureus cause?
Inflammatory- skin infections, organ abscesses, pneumonia
Toxin- TSST, SSS
TSST is a superantigetn
What is the toxin involved in scalded skin syndrom
Which toxin causes food poinsoning?
enterotoxins (heat stabile)
What is the role of hyaluronidase?
breaks down proteoglycans in CT
What is the role of staphylokinase?
lyses formed fibrin clots
What are the symptoms of Toxic Shock Syndrome?
high fever, nausea, vomiting, watery diarrhea are sudden
diffuse erythema comes on a little later
When is Staph epidermidis a problem?
Hospitalized patients with IVs or Catheters.
Who gets S. Saprophyticus?
women, common community aquired UTI.