Quick Review Cards for Medical Laboratory Science

Commonly Isolated

Enterobacteriaceaecontinued

Clinical Microbiology Review 183

KEY REACTIONS

ORGANISM PATHOGENICITY POSITIVE NEGATIVE OTHER

Salmonella

Citrobacter freundii

Klebsiella pneumoniae

Enterobacter aerogenes
&cloacae

Found in poultry. May be transmitted

by reptiles. S. typhihas Vi antigen,

only trace H 2 S, citrate neg. Grouped

by O antigens (e.g., A, B, C), serotyped

by H antigens (e.g., 1, 2).

Lactose variable. ONPG & LDC

differentiate from Salmonella.

Encapsulated. Colonies usually

mucoid. Some strains hydrolyze

urea slowly. K. oxytocais similar to

K. pneumoniaeexcept indole pos.

Motility & ODC differentiate from

Enterobacter.

Colonies may be mucoid. Same

IMViC reactions as Klebsiella.

Typhoid (enteric) fever,

bacteremia, enterocolitis

Nosocomial infections

Pneumonia, UTI,

septicemia

Opportunistic & nosoco-

mial infections. UTI, RTI,

& wound infections

H 2 S, MR, motility,

lysine decarboxylase

(LDC)

Gas, H 2 S, MR, citrate,

motility, ONPG

Lactose, gas, VP,

citrate, urease (slow)

Lactose, gas, VP,

citrate, motility, ODC

Lactose, indole,

VP, PD, urease,

ONPG

VP, PD, LDC

H 2 S, indole, MR,

PD, motility,

ornithine decar-

boxylase (ODC)

H 2 S, indole, MR,

PD

continued...