Applied and Environmental Microbiology 2000-07-01

Modification of sorbitol MacConkey medium containing cefixime and tellurite for isolation of Escherichia coli O157:H7 from radish sprouts.

T Fujisawa, S Sata, K Aikawa, T Takahashi, S Yamai, T Shimada

Index: Appl. Environ. Microbiol. 66(7) , 3117-3118, (2000)

Full Text: HTML

Abstract

A modified version of sorbitol MacConkey medium containing cefixime and tellurite (CT-SMAC medium) was produced by adding salicin and 4-methylumbelliferyl-beta-D-galactopyranoside to CT-SMAC medium; this medium was designated CT-SSMAC medium and was used to isolate Escherichia coli O157:H7 from radish sprouts. Of 101 non-E. coli bacteria isolated from radish sprouts that produced colorless colonies similar to colonies of E. coli O157:H7 grown on CT-SMAC medium, 92 (91%) formed colonies that were red to pink or were beta-galactosidase negative and colorless on CT-SSMAC medium. On the other hand, colonies of E. coli O157:H7 strains were colorless and beta-galactosidase positive on CT-SSMAC medium. Our results suggest that CT-SSMAC medium is more selective than CT-SMAC medium for isolating E. coli O157:H7.