Evaluation of sorbitol-salicin MacConkey medium containing cefixime and tellurite (CT-SSMAC medium) for isolation of Escherichia coli O157:H7 from raw vegetables.

The utility of CT-SSMAC medium (sorbitol-salicin MacConkey medium containing cefixime and tellurite) for the isolation of Escherichia coli O157:H7 from raw vegetables was investigated. The colonies of all E. coli O157:H7 and O157:NM strains tested were colorless and beta-galactosidase-positive on CT-SSMAC medium. Furthermore, the number of colorless colonies on the CT-SSMAC medium was less than that on the sorbitol MacConkey medium containing cefixime and tellurite (CT-SMAC medium) from several raw vegetable samples. All colorless colonies grown on CT-SSMAC medium from raw vegetable samples were beta-galactosidase-negative. These findings suggest that the CT-SSMAC medium is useful for the isolation of E. coli O157:H7 from raw vegetable samples.