Colorex O157

Focus on E.coli O157

Escherichia coli (E. coli) are bacteria commonly found in the gut of humans and warm-blooded animals. Most strains of E. coli are harmless. Some strains, however, such as Verocytotoxigenic E. coli (VTEC), also known as Shigatoxigenic E. coli (STEC) can cause severe foodborne diseases. Enterohaemorrhagic E. coli (EHEC) are a subset of VTEC, which can cause severe disease in humans such as Haemolytic Uraemic Syndrome (HUS). VTEC have been isolated from the gut contents of many animals, including cattle and sheep. VTEC are mainly transmitted to humans primarily through consumption of contaminated foods, but can also be transmitted through handling animals carrying these bacteria.

Medium Performance

Easier detection: E.coli O157 is detected by a characteristic mauve colour after only 18 h of incubation, while most other E. coli are blue.

Higher specificity of Colorex™ E.coli O157 compared to SMAC:

The conventional medium for the detection of E.coli O157 is Sorbitol MacConkey (SMAC) Agar, which has very poor specificity, thus exhibiting an abundance of false positives (Proteus, E.hermanii, etc.). Sorbitol Mac Conkey is also difficult to read because there is a change of colouration in the case of prolonged incubation.