Microbio Flashcards
How to differentiate Citrobacter and E. coli?
Citrate
Citrobacter (+)
E. coli (-)
How to separate Enterobacter and Klebsiella?
Motility and ODC
Enterobacter (+)
Klebsiella (-)
How to differentiate Enterobacter species?
Lysine
E. aerogines (+)
E. cloacae and sakazakii (-)
How to differentiate Serratia from other non-lactose fermenter Enterobacteriaceae?
MR
Shigella (-)
How to differentiate S. dysenteriae from other shigella sp?
Mannitol (-)
Differentiate S. sonnei and S. flexneri & boydii by?
ONPG
S. sonnei (+)
S. flexneri & boydii (-)
How to differentiate E. tarda and Salmonella (both are LDC (+))
Indole
E. tarda (+)
Salmonella (-)
Characteristics of Enterobacteriaceae
Gram neg rods
Oxidase (-)
Catalase (+)
Nitrate —> nitrite
Facultative anaerobe
Ferments glucose
MRSA
Beta lactamase inactivates penicillin/ampicillin
Treat with vancomycin
How to differentiate Micrococcus from coagulase neg staph
Oxidase/microdase (+)
Bacitracin/lysostaphin (S)
S. epidermidis
Glycocalyx
Nosocomial - surgical wounds, catheter = UTI, endocarditis
Opportunistic
S. agalactiae
Bile pos
Meningitis and pneumonia and neonatal sepsis in babies
Antiphagocytic capsule contains sialic acid
S. pneumoniae
Lancet shaped/in pairs
Wet colonies
Quellung reaction (+) - capsular swelling
Req CO2, brain-heart infusion agar, TSA, chocolate
Polysaccharide capsule protects from phagocytosis
Adults: pneumonia and meningitis
Children: otitis media
S. Viridans
URT normal flora
Dental caries
Subacute bacterial endocarditis
S. anginosus: grows in decreased O2, brain/abdominal abscess
S. aureus & intermedius
Salt tolerant
Beta hemolytic
Exfoliative/enterotoxin —> scalded skin syndrome
Hyaluronidase
Toxic shock syndrome with tampons
50% of people carry it in skin and nares
