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Medical micro
Medical micro bacteria
| bacteria | gram stain, features | labs | clinical facts | virulence factors | mechanism of resistance | source/transmisiion |
|---|---|---|---|---|---|---|
| staph. aureus | gm+, cocci in clusters, yellow gold b-hemolytic colonies, FA, | cata+, coag+, ferments mannitol, grows on 6.5% NaCl | gasteroenteristis, enterotoxinA; toxic shock syn; skin infec, scalded skin syn; bacteremia, osteo; pneum, noso; parotitis | exotoxins: alpha hemolysin, enterotoxin A, superantigin, exfoliatin; coagulase, protein A, hyaluronidase; protease; lipase; firbrolysin; nuclease | b-lactamase, mutant PBP | colonizes human skin and nose; trans - hands |
| staph. epi | gm+, cocci in clusters, white colonies on BA | cata+, coag-, novobiocin sensitive, gamma hemolysis | bacteremia - iatrogenic, drug abusers, may progress to subacute endocarditis in valves | glycocalyx; enables adhesion, resistance to phagocytosis | plasmid coded - b-lactamase, mutatnt PBP, meth resis | normal flora of the skin and mucosa |
| staph. saprophyticus | gm+cocci in clusters, white/yellow colonies on BA | cata+, coag-, novobiocin resitant, gama hemolysis | UTI - pylonephritis, cystitis; young sexually active females | hemagglutinin/surface proteins, mediates attachment; urease, permits colonization causing UTI and promotes renal stone formation | plasmid coded b-lactamase, mutant PBP, meth resistant | normal flora of GU skin |