VIRULENCE PROPERTIES OF ESCHERICHIA-COLI STRAINS BELONGING TO ENTEROPATHOGENIC (EPEC) SEROGROUPS ISOLATED FROM CALVES WITH DIARRHEA

Nineteen Escherichia coli strains belonging to enteropathogenic (EPEC) serogroups were isolated from calves with diarrhea in Parana State, B razil, and studied for virulence markers associated with EPEC or enter ohemorrhagic E. coli (EHEC). The 19 isolates belonged to 12 serotypes with isolates of O26:H11, O119:H25 and O114:H- being the most prevalen t. Localized adherence (LA) was demonstrated for 37% of the isolates, consisting of all four O26:H11, both O114:H- and one O114:H40 isolates . All the LA strains were positive in the fluorescent-actin staining ( FAS) test and possessed attaching-effacing E. coli (eae) sequences, bu t only O114 strains hybridized with the EPEC adherence factor (EAF) pr obe. None of the strains produced Shiga-like toxins (Verotoxin). Only the O26:H11 strains hybridized with the EHEC plasmid specific (CVD419) probe and were enterohemolytic, properties associated with EHEC strai ns. This investigation demonstrates that among the bovine strains isol ated only those of serogroup O114 behaved as typical EPEC.