OCCURRENCE OF VEROTOXIN-PRODUCING STRAINS OF ESCHERICHIA-COLI O157-H7IN FECAL SAMPLES OF CALVES IN TYROL

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 were cultured from 8 of 500 (1.6 %) examined faecal samples from carves of Tyrol (Austria) . Seven of 181 (3.8 %) examined dairy herds located in different distr icts of Tyrol were found positive for EHEC O157:H7. The eight bovine O 157:H7 isolates were cytotoxic for Vero cells and produced verotoxin 2 . All 8 strains carried EHEC O157:H7 specific, phenotypical traits lik e production of enterohemolysin and absence of sorbitol-fermentation a nd beta-glucuronidase-activity. Epidemiological relationships between the isolates were investigated by comparing restriction fragment lengt h polymorphisms of Xbal cleaved total DNA by pulsed-field gel electrop horesis. By this, most isolates were found epidemiologically closely r elated and in 2 cases the same clonal type was found in different anim als.