MULTIPLE SOURCES OF ESCHERICHIA-COLI O157 IN FEEDLOTS AND DAIRY FARMSIN THE NORTHWESTERN USA

Samples from cattle, other domestic and wild animals, flies, feeds, an d water-troughs were collected from 12 cattle farms and tested for Esc herichia coli O157. E. coli O157 was isolated from bovine fecal sample s on all 12 farms with a within herd prevalence ranging from 1.1% to 6 .1%. E. coli O157 was also found in 1 of 90 (1.1%) equine fecal sample s, 2 of 65 (3.1%) canine fecal samples, 1 of 200 pooled bird samples ( 0.5%), 2 of 60 pooled fly samples (3.3%), and 10 of 320 (3.1%) water-t rough sample sets (biofilm and water). No E. coli O157 were isolated f rom 300 rodents, 33 cats, 34 assorted wildlife, or 335 cattle feed sam ples. Indistinguishable pulsed-field gel electrophoresis patterns of X baI digested chromosomal DNA and Shiga toxin types were observed for b ovine and water-trough isolates from two farms and for one equine and two bovine isolates from one farm. (C) 1998 Elsevier Science B.V.