Comparison of Salmonella chromogenic medium with DCLS agar for isolation of Salmonella species from stool specimens.

Salmonella chromogenic medium (SCM; Oxoid, Basingstoke, United Kingdom), a new selective chromogenic medium, was compared to DCLS agar (Oxoid) for the detection and presumptive identification of Salmonella species from stool samples. This medium contains two chromogenic substrates, Magenta-cap (5-bromo-6-chloro-3-indolylcaprylate), which is hydrolyzed by Salmonella species to give magenta colonies, and X-Gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside), which is incorporated to visualize beta-D-galactosidase-producing organisms as blue colonies. Thus, non-Salmonella organisms appear blue or are not stained by any of the chromogens of the medium.