Virulence attributes of Escherichia coli isolated from dairy heifer feces

Escherichia coli isolates from 1,305 (of 6,894) fecal samples collected during the 1991–1992 USDA, Animal and Plant Health Inspection Service, National Animal Health Monitoring System, Dairy Heifer Evaluation Project were tested for virulence attributes associated with human enterohaemorrhagic E. coli (EHEC) and the enterotoxin commonly associated with diarrhoea in newborn calves. Single, random isolates from each heifer were hybridized to probes derived from the 60 mDa EHEC plasmid (CVD 419), E. coli attaching and effacing gene ( eae), Shiga-like toxin ( slt) genes I and II, and E. coli heat-stable enterotoxin a (STaP). Seventy-seven of the 1305 isolates (5.9%) were slt-positive. Most (81.8%) slt-positive E. coli were also CVD 419 and eae-positive. Only 2 of the slt-positive E. coli isolates were STaP-positive.