CHARACTERISTICS OF VERO CYTOTOXIN-PRODUCING ESCHERICHIA-COLI ASSOCIATED WITH INTESTINAL COLONIZATION AND DIARRHEA IN CALVES

Isolates of Escherichia coli which produce Vero cytotoxin (VTEC) were obtained during 1983-1989 from calves raised in 5 north-central states of the USA. All of the calves experienced intestinal epithelial colon ization by VTEC, diarrhea or both; twelve of the calves had bloody dia rrhea. Twenty one isolates were serogroup O111 and the others were O10 3, O69, O45, O26, O5, or non-typable (4 isolates). All but one of the isolates hybridized with the CVD419 probe which identifies most VTEC s trains. Thirty two isolates hybridized with the VT1 probe, 3 with both the VT1 and VT2 probes, and one with neither probe. The culture filtr ate of the VT probe negative isolate was partially neutralized by SLT I monoclonal antibody. For the other isolates, the results of toxin ne utralization by anti-SLT I and anti-SLT II monoclonal antibodies corre sponded exactly with the VT1 and VT2 probe hybridization results. Thre e of the strains adhered in a localized manner to HEp-2 cells and Inte stine 407 cells.