Routine Media for Aerobes and Facultative
Anaerobescontinued
Clinical Microbiology Review 150
MEDIUM TYPE FOR ISOLATION OF OTHER
Hektoen enteric (HE) agar
Xylose lysine deoxycholate
(XLD)
Salmonella-Shigella (SS) agar
Gram-negative broth (GN)
Bile salts, bromothymol blue, & acid fuchsin inhibit
normal GI flora. Nonpathogens orange to salmon pink.
NLF green to blue-green. H 2 S-pos colonies have black
precipitate.
Deoxycholate inhibits many GNR & GP. 4 types of colonies:
yellow (e.g., E. coli), yellow with black centers (e.g.,
some Proteusspecies), colorless or red colonies (e.g.,
Shigella), red colonies with black centers (e.g., Salmonella).
(Some shigellae may be inhibited. Some salmonellae
may not produce H 2 S.)
Brilliant green & bile salts inhibit other enterics.
Salmonella& Shigelladon’t ferment lactose (colorless
colonies). Salmonellaproduces H 2 S (black center).
Deoxycholate & citrate salts retard growth of GP. Sub-
culture onto selective differential agar after 6–8 hr &
18–24 hr incubation. Use of enrichment broths for stool
cultures is decreasing.
S, D
S, D
S
E, S
Salmonella& Shigellain stool
Salmonella& Shigellain stool
Salmonella& Shigellain stool
Salmonella& Shigellafrom
stools & rectal swabs
continued...
