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12 Cards in this Set
- Front
- Back
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Staphylococci – catalase positive
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-S. aureus = coagulase positive ("our staff is really...coagulating)
-coagulase negative: S. epidermidis, S. saphrophyticus --S. epidermidis is nobobios(k)in sensitive --S. saphrophyticus is nobobios(k)in resistant |
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Streptococci – alpha hemolytic
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-hemolysis -->
partial/green = alpha hemolytic = S. pneumoniae, S viridans (e.g., S. mutans) pneumonia wants to be a COB (like the rods) -Capsule -Optochin sensitive -Bile-soluble viridans is a green mutant -no COB |
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Streptococci – beta hemolytic
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Group A
pie on my jeans, use bacitracin -Strep pyogenes, bacitracin sensitive Group B no galaxy, no bacitracin -S. agalactiae, bacitracin resistant |
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Streptococci – gamma hemolytic
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-no hemolysis
-Denterococcus --Enterococcus (Group D Strep) --E. faecalis – poop grows in bile and salt water --grows in bile and 6.5% NaCl -Non-denterococus --S. bovis – cows grow in bile, but drown in salt water --grow in bile, but not 6.5% NaCl |
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Beta-hemolytic bacteria
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-Strep pyogenes
--group A strep – catalase negative, bacitracin sensitive -Strep agalacitae --group B strep – catalase negative, bacitracin resistant -Staphylococcus aureus – catalase positive, coagulase positive -Listeria monocytogenes (gram-positive rod/"cob") --tumbling motility, meningitis in newborns, unpasteurized milk |
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Staphylococcus aureus
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-coagulase positive
-catalase positive -gram-positve cocci in clusters -protein A is virulence factor – binds Fc-IgG, INHIBITING COMPLEMENT ACTIVATION AND PHAGOCYTOSIS -commonly colonizes the nose |
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Staph aureus disease
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-inflammatory disease
--skin infections, organ abscesses, pneumonia (often after influenza virus infection) --endocarditis, osteomyelitis -toxin-mediated disease --rapid-onset food poisoning (enterotoxins --scalded skin syndrome (exfoliative toxin) --toxic shock syndrome (TSST-1 toxin) -MRSA (methicillin-resistant S. aureus) --important cause of serious nosocomial and community-acquired infections --resistant to methicillin and nafcillin because of altered penicillin-binding protein |
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TSST
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-superantigen of Staph aureus
-binds to MCH II and T-cell receptor --> polyclonal T-cell activation -presents as fever, coming, rash, desquamation, shock, end-organ failure -use of vaginal or nasal tampons predisposes to toxic shock syndrome |
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Staph aureus food poisoning
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-caused by ingestion of preformed toxin
--> short incubation period (2-6 hours) --enterotoxin is heat stable, so not destroyed by cooking |
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Staph – catalase and coagulase
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"Staph makes catalase because it has more staff to do so."
Bad staph (aureus) makes coagulase and toxins, too. -Forms fibrin clot around self --> abscess. |
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Staphylococcus epidermidis
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-catalase positive, coagulase negative, nobobioSKIN sensitive
-infects prosthetic device and IV catheters by producing adherent biofilms (immune cells can't get through "the crowd" of bacteria) -Component of normal skin flora -contaminates blood cultures -sensitive to NovobioSKIN (novobiocin) |
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Staphylococcus saprophyticus
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-catalase positive, coagulase negative, novobioSKIN resistant
-second most common cause of uncomplicated UTI in young women (first is E. coli) -resistant to novobiocin |
