VIRULENCE ATTRIBUTES OF ESCHERICHIA-COLI ISOLATED FROM DAIRY HEIFER FECES

Escherichia coil isolates from 1,305 (of 6,894) fecal samples collecte d during the 1991-1992 USDA, Animal and Plant Health Inspection Servic e, National Animal Health Monitoring System, Dairy Heifer Evaluation P roject were tested for virulence attributes associated with human ente rohaemorrhagic E. coil (EHEC) and the enterotoxin commonly associated with diarrhoea in newborn calves. Single, random isolates from each he ifer were hybridized to probes derived from the 60 mDa EHEC plasmid (C VD 419), E. coil attaching and effacing gene (eae), Shiga-like toxin ( sit) genes I and II, and E. coli heat-stable enterotoxin a (STaP). Sev enty-seven of the 1305 isolates (5.9%) were sir-positive. Most (81.8%) sit-positive E. coil were also CVD 419 and ene-positive. Only 2 of th e sit-positive E. coil isolates were STaP-positive.