-
gram +
- staph
- strep
- clostridium
- corynebacterium
- bacillus
- listeria
- mycobacterium
- actinomyces & nocardia (branching)
-
encapsulated bacteria
- Some Killers Have Pretty Nice Capsules
- Salmonella
- Klebsiella
- Haemophilus influenza B (hib)
- Pneumococcus (strep pneumo)
- Neisseria meningitidis (NOT gonococci)
- Cryptococcus
-
ID-ing staph
- NO StRES
- NOvobiocin: Saprophyticus is Resistant ; Epidermidis is Sensitive
both are gamma hemolytic (non hemolytic)
-
ID-ing Strep
OVRPS (overpass): Optochin - Viridans is Resistant; Pneumo is Sensitive; these are alpha hemolytic
B-BRAS: Bacitracin - group B strep (agalactiae) are Resistant; group A strep (pyogenes) are Sensitive); these are beta hemolytic
-
cAMP inducers
- CAEP
- Cholera (vibrio): permanently activates Gs - rice water diarrhea
- Anthrax (bacillus): includes edema factor (bacterial adenylate cyclase)
- ETEC: heat labile toxin
- Pertussis toxin: permanently disables Gi, causing whooping cough
-
strep pneumo
- MOPS: meningitis, otitis media, penumonia, sinusitis (mcc)
- trigger: G+ diplo, capsule, optochin sensitive, polysaccharide vaccine, IgA protease
- alpha hemolytic
- tx: PCN, amoxicillin, FQ, macrolides
-
strep pyogenes
- GROUP A STREP
- pyogenic: pharyngitis, cellulitis, impetigo
- toxigenic: scarlet fever, TSS
- immunologic: rheumatic fever (M protein), acute GN
- trigger: bacitracin sensitive, beta hemolytic, M protein, G+ cocci in chains, streptolysin O & S, PYR+
- lab: catalase neg, ASO titer for RFever
- tx: PCN, cephalosporin, erythromycin
-
Rheumatic Fever
- develops a few weeks after GAS (pyogenes) pharyngitis
- AB develop against GAS M proteins: cross react and cause T2HS, also CMI: T4HS
- Sx: Polyarthritis, SubQ plaques, erythema marginatum, chorea, carditis (most serious: pericarditis, myocarditis - MCC of death, endocarditis - MV - sterile vegetations)
- lab: ASO titers>400, increased anti-DNase B titers
- tx: PCN, aspirin, CS for carditis and heart failure if murmur is present
-
strep agalactiae
- GROUP B STREP
- Bacitracin resistant, beta hemolytic
- pneumonia, meningitis, sepsis - mainly in babies (transmitted at birth, mainly in prolonged labor)
- give prophylaxis at delivery
- tx: ampicillin, aminoglycosides, cephalosporin
-
Enterococci (e. faecalis, e. faecium)
- UTI, subacute endocarditis
- penicillin resistant, nosocomial
- post GI/GU surgery - endocarditis on previously damaged heart valves
- lab: bile-esculin test, optochin resistant
- tx: aminoglycoside+ ampicillin/vanc. if FQ resistant, linezolid and newer abx
-
viridans strep
- (mutans & sanguis)
- alpha hemolytic (green hemolysis), optochin resistant
- dental caries, endocarditis
- tx: PCN +/- aminoglycoside
- produce dextrans w/sucrose as substrate - facilitate adherance to fibrin @ endothelial trauma, fibrin and platelets aggregate and become sites for adherance and colonization
-
staph aureus
- Protein A binds Fc-IgG, inhib complement and phagocytosis
- coagulase & catalase + (grapelike clusters)
- beta hemolytic
- TSST: TSS, food poisoning, scalded skin syndrome
- MRSA
- Inflammatory skin disease: impetigo, carbuncle
- tx: methicillin, nafcillin, oxacillin, vanc for MRSA
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