Occurrence of Escherichia coli O157:H7 in faeces, skin and carcasses from sheep and goats in Ethiopia.

AIMS

To determine the occurrence and proportion of Escherichia coli O157:H7 in faeces, skin swabs and carcasses before and after washing, from sheep and goats in Ethiopia.

METHOD AND RESULTS

Individual samples were enriched in modified tryptic soy broth with novobiocin, concentrated using immunomagnetic separation (IMS) and plated onto cefixime-tellurite containing sorbitol MacConkey agar. Presumptive colonies were confirmed by biochemical tests and subjected to latex agglutination tests. A PCR was performed on isolates for the detection of stx(1), stx(2) and eae genes. Escherichia coli O157:H7 was isolated from faeces (4.7%), skin swabs (8.7%) and carcasses before washing (8.1%) and after washing (8.7%) and on water samples (4.2%). The proportion of carcasses contaminated with E. coli O157:H7 was strongly associated with those recovered from faecal and skin samples. Both stx(1) and stx(2) genes were identified from one E. coli O157:H7 isolate from a goat carcass.

CONCLUSIONS

Even though the numbers of samples examined in this study were limited to one abattoir, sheep and goats can be potential sources of E. coli O157:H7 for human infection in the country. Control measures to reduce the public health risks arising from E. coli O157:H7 in reservoir animals need to be addressed at abattoir levels by reducing skin and faecal sources and carcass contaminations at different stages of slaughter operations.

SIGNIFICANCE AND IMPACT OF THE STUDY

Escherichia coli O157:H7 was detected from carcasses before and after washing during slaughtering operations, and one O157 isolate was positive for verotoxins.