Hydrochloric acid treatment for rapid recovery of Shiga toxin-producing Escherichia coli O26, O111 and O157 from faeces, food and environmental samples.

We developed a hydrochloric acid treatment for the isolation of Shiga toxin-producing Escherichia coli (STEC) O26:H11, O111:H- and O157:H7 strains from a variety of samples. After exposure to an equal volume of 1/8N HCl solution for 30 sec, the fecal suspensions and enrichment cultures were spread onto cefixime-tellurite-sorbitol-MacConkey (CT-SMAC) agar. This HCl treatment increased the sensitivity for detection of STEC O26:H11, O111:H- and O157:H7 strains and decreased the growth of other microorganisms, from faecal samples and enrichment cultures of a variety of samples. This approach is an important economical and time-saving method to simplify and speed up isolation of STEC O26:H11, O111:H- and O157:H7 from a variety of samples.