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 center dot 7%), skin swabs (8 center dot 7%) and carcasses before washing (8 center dot 1%) and after washing (8 center dot 7%) and on water samples (4 center dot 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.