MICROcardsBACTERIArevisedARA1

MICROcardsBACTERIArevisedARA1 - Staphylococcus aureus =...

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Unformatted text preview: Staphylococcus aureus = major Staph pathogen aureus = gold Lab I D G+ grape-like clusters catalase(+) coagulase(+) golden-yellow pigment (from carotenoids) all Staph = cat(+) all Strep = cat(-) S. aureus is only Staph that is coagulase (+) Metabolism- facultative w/ ETC often Penicillin G resistant Other Unique Features- thermostable nucleus (+)- cells divides perpendicular to last plane of division- Ribitol in teichoic acid- high salt tolerance (e.g. can grow on salted meats)- can ferment mannitol organic acids- long stationary phase other Staph are thermostable (-) Vi rulence Factors Protective- protein A (binds IgG to prevent phago/ ops)- coagulase (fibrin formation, α phago)- hemolysins- leukocidins- penicillinase Tissue-destroying- hyaluronidase (breaks down proteog in CT)- staphylokinase (lyses formed fibrin clots)- lipase (disseminate)-clumping factor (adhere to fibrinogen, α uptake) Host defense mechanisms include: skin, group I IA phospholipase A (from platelets), PMN-C3 opsonization & Ab to toxins- α hemolysin forms pores (most potent), ß lysis- leukocidin PMN lysis + LT 4 + I L-8 inflamm- Exfoliative exotoxin scalded skin syndrome- Enterotoxin (SE) food poisoning, superAg- TSST-1 IL1B +TNF TSS, agr-quorum sensing hemolysins & leukocidin lyse cells by creating pores in the membrane Associated Diseases Exotoxin-dependent * Gastroenteritis (“food poisoning”) * Toxic Shock Syndrome (can be lethal!)- high fever, nausea & vomiting, watery diarrhea- erythematous rash, HoTN- desquamation of palms & soles (late) * Scalded Skin Syndrome , Bullous Impetigo NOT normal flora, but transiently colonizes nasopharynx of ~30% pop. can colonize -Cellulitis, abscess, furuncle, carbuncle, wound inf. Direct Invasion (tend to be localized) * Pneumonia * Meningitis * Osteomyelitis (boys <12) * Acute bacterial endocarditis – rapid veg growth * Bacteremia/sepsis, Septic arthritis – synovial fluid * Skin: folliculitis, carbuncles, abscesses, cellulitis * UTI nasopharynx, skin, vagina ↑ risk in medical personnel, diabetics & IV drug users Diagnosis- Culture- PCR detection of ribosomal RNA MRSA! T reatment(s)- penicilinase-resistant penicillins (e.g. Methicillin )- Vancomycin if Methicillin-resistant (MRSA)- Clindamycin no protective immunity; infxn can be aquired over & over Early onset (<5d) ALL capsule types Lat e onset (5-30 d) Capsule type I I I mostly (70-80%) More to come next quarter More to come next quarter More to come next quarter More to come next quarter More to come next quarter More to come next quarter More to come next quarter More to come next quarter More to come next quarter More to come next quarter mediat e att achment More to come next quarter More to come next quarter More to come next quarter Gram stain under microscope Culture on blood agar Staphylococcus saprophyticus Lab I D G+ grape-like clusters catalase(+) coagulase(-) all Staph = cat(+) all Strep = cat(-) Metabolism- facultat ive w/ ETC...
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This note was uploaded on 09/14/2011 for the course PHARM mb taught by Professor Staff during the Spring '11 term at UCSD.

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MICROcardsBACTERIArevisedARA1 - Staphylococcus aureus =...

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