Prevalence of verotoxin-producing Escherichia coli (VTEC) in feces of healthy beef cattle and sheep in Switzerland

Fecal samples from 544 beef cattle and 140 sheep were investigated by PCR f or verotoxin (VT)-producing Escherichia coli (VTEC) without and with an enr ichment step, 6.1% (after enrichment 14%) of cattle samples and 10% (after enrichment 29.2%) of sheep samples were VT-PCR-positive. Moreover, a notice able age-depending prevalence in cattle was found. Eleven VTEC strains isolated from fecal samples of 5 cattle and 6 sheep wer e taken for further characterization. None of the strains belonged to serog roup O157. But, as reported previously, we also found in this study strains with virulence genes that hare associated with increased pathogenicity. The importance of slaughter hygiene and of bacteriological monitoring of ca rcass contamination has to be pointed out.