Shiga-Like Toxin-Producing E.Coli in Sarda Slaughtered Sheep : DIRECT DETECTION OF VIRULENCE GENES AND MOLECULAR CHARACTERIZATION OF NON-O157 ISOLATES

Healthy sheep carry shiga-like toxin-producing Escherichia coli (STEC) at similar rates to cattle but examples of disease-associated E. coli in sheep are rare and none refers. A study of pathogenic Escherichia coli in Sarda sheep at slaughter, on carcasses, fleeces, gut and faeces was performed. Nineteen sampling sessions were carried out in industrial capacity slaughterhouses. The aim of the present study was to evaluate the role of the sheep as STEC reservoir and to detect the prevalent serogroups over the sheep chain production. In order to make a preliminary screening of STEC in collected samples, a simplex PCR was performed on all the specimens. Virulence profile characterization of the isolates showed a significant level of STEC strains (22.6%) and a higher number of EPEC (53.8%). Furthermore, virulence accessory factors are widely detected, assigning an additional pathogenic capacity to the strains, and very complex virulence profiles. Serotyping assays proved that Sarda sheep carried mainly non-O157 E. coli, including O91 serogroup, the role of these pathogroup in Public Health must not be underestimated.