Streptococci/Enterococcicontinued Clinical Microbiology Review 162
ORGANISM PATHOGENICITY GRAM STAIN COLONIES ON SBA KEY CHARACTERISTICS OTHER
Group B streptococci
(GBS)
Group D streptococci,
nonenterococci
Enterococcus
S. agalactiae. Vaginal &
rectal swabs collected
from pregnant women
at 35–37 wk gestation.
Inoculated in selective
broth, e.g., LIM, GBS
broth, StrepB Carrot
Broth.
Most common is
S. gallolyticus (formerly
S. bovis).
Lancefield group D.
80% are E. faecalis,
15% E. faecium.
Oval GPC in chains
Oval GPC in chains
Oval GPC in pairs &
chains
Slightly larger than
GAS. Gray-white.
Narrow zone of
diffuse beta
hemolysis. May
be nonhemolytic.
Usually non-
hemolytic. May be
alpha hemolytic.
Usually alpha or
nonhemolytic.
Rarely beta.
Normal flora of fe-
male genital tract.
Most common
cause of neonatal
septicemia &
meningitis
Normal in GI tract.
Causes nosocomial
UTI, wound infec-
tions, bacteremia
Normal in mouth,
GI tract, female
genital tract. Causes
nosocomial UTI,
wound infections,
bacteremia
Resistant to SXT & baci-
tracin. Sodium hippu-
rate pos. CAMP pos
Hydrolyzes esculin
Hydrolyzes esculin.
Grows in 6.5% NaCl
broth. PYR pos
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