Bacteria Guide 01

Bacteria Guide 01 - = major Staph pathogen aureus = gold...

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Staphylococcus aureus = major Staph pathogen aureus = gold Lab ID 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 - thermonstable 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 (-) Virulence 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 IIA phospholipase A (from platelets), PMN-C3 opsonization & Ab to toxins - α hemolysin forms pores (most potent), ß lysis - leukocidin PMN lysis + LT 4 + IL-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 -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 NOT normal flora, but transiently colonizes nasopharynx of ~30% pop. can colonize nasopharynx, skin, vagina risk in medical personnel, diabetics & IV drug users Diagnosis - Culture - PCR detection of ribosomal RNA MRSA! Treatment(s) - penicilinase-resistant penicillins (e.g. Methicillin ) - Vancomycin if Methicillin-resistant (MRSA) - Clindamycin no protective immunity; infxn can be aquired over & over Gram stain under microscope Culture on blood agar
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Staphylococcus saprophyticus Lab ID G+ grape-like clusters catalase(+) coagulase(-) all Staph = cat(+) all Strep = cat(-) Metabolism - facultative w/ ETC Other Unique Features - thermostable nucleus (-) - cells divide perpendicular to last place of division - Glycerol in teichoic acid - cannot ferment mannitol - “ γ hemolysis” on blood agar Virulence Factors Associated Diseases * UTI - causes 10-20% of 1 ° UTIs in young - 90% are symptomatic Treatment(s) - Penicillin - Novobiocin resistant compare S. epidermidis
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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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Bacteria Guide 01 - = major Staph pathogen aureus = gold...

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