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Staphylococcus aureus= major Staphpathogen aureus = goldLab IDG+ grape-like clusterscatalase(+)coagulase(+)golden-yellow pigment(from carotenoids)all Staph = cat(+)all Strep = cat(-)S. aureus is only Staph that is coagulase (+)Metabolism- facultative w/ ETCoften Penicillin G resistantOther Unique Features- thermostable nucleus (+)- cells divides perpendicular to last plane of division- Ribitolin teichoic acid- high salt tolerance (e.g. can grow on salted meats)- can ferment mannitolorganic acids- longstationary phaseother Staph are thermostable (-)Virulence FactorsProtective- protein A(binds IgG to prevent phago/ops)- coagulase (fibrin formation, αphago)- hemolysins- leukocidins- penicillinaseTissue-destroying- hyaluronidase (breaks down proteog in CT)- staphylokinase (lyses formed fibrin clots)- lipase (disseminate)-clumping factor (adhere to fibrinogen, αuptake)Host defense mechanisms include: skin, group IIA phospholipase A (from platelets), PMN-C3 opsonization & Ab to toxins- αhemolysin forms pores (most potent), ß lysis- leukocidin PMN lysis + LT4+ IL-8 inflamm- Exfoliative exotoxinscalded skin syndrome- Enterotoxin (SE)food poisoning, superAg- TSST-1IL1B +TNF TSS, agr-quorum sensinghemolysins & leukocidin lyse cells by creating pores in the membraneAssociated DiseasesExotoxin-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 ImpetigoNOT 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* UTInasopharynx, skin, vagina↑risk in medical personnel, diabetics & IV drug usersDiagnosis- Culture- PCR detection of ribosomal RNAMRSA!Treatment(s)- penicilinase-resistant penicillins (e.g. Methicillin)- Vancomycin if Methicillin-resistant (MRSA)- Clindamycinno protective immunity; infxn can be aquired over & over
Early onset (<5d)ALL capsule typesLate 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 mediate attachmentMore to come next quarter More to come next quarter More to come next quarter Gram stain under microscopeCulture on blood agar
Staphylococcus saprophyticusLab IDG+ grape-like clusterscatalase(+)coagulase(-)all Staph = cat(+)all Strep = cat(-)Metabolism- facultative w/ ETCOther Unique Features- thermostable nucleus(-)- cells divide perpendicular to last place of division- Glycerol in teichoic acid- cannotferment mannitol- “γhemolysis” on blood agarVirulence FactorsAssociated