title: Environmental sources and transmission of Escherichia coli O157 in feedlot cattle.
abstract: A study was conducted in 2 feedlots in southern Alberta to identify environmental sources and management factors associated with the prevalence and transmission of Escherichia coli O157:H7. Escherichia coli O157:H7 was isolated in preslaughter pens of cattle from feces (0.8%), feedbunks (1.7%), water troughs (12%), and incoming water supplies (4.5%), but not from fresh total mixed rations. Fresh total mixed rations did not support the growth of E. coli O157:H7 and E. coli from bovine feces following experimental inoculation. Within a feedlot, the feces, water troughs, and feedbunks shared a few indistinguishable subtypes of E. coli O157:H7. A few subtypes were repeatedly isolated in the same feedlot, and the 2 feedlots shared a few indistinguishable subtypes. The prevalence of E. coli O157:H7 in water troughs of preslaughter cattle in 1 feedlot was associated with season, maximum climatic temperatures the week before sampling; total precipitation the week before sampling, and coliform and E. coli counts in the water trough.
authors.affiliation: 11 Bruns Road, Lacombe, Alberta T4L 1P1, Lakeside Research, Box 800, Brooks, Alberta.
authors.forename: J
authors.initials: J
authors.lastname: Van Donkersgoed
authors.forename: J
authors.initials: J
authors.lastname: Berg
authors.forename: A
authors.initials: A
authors.lastname: Potter
authors.forename: D
authors.initials: D
authors.lastname: Hancock
authors.forename: T
authors.initials: T
authors.lastname: Besser
authors.forename: D
authors.initials: D
authors.lastname: Rice
authors.forename: J
authors.initials: J
authors.lastname: LeJeune
authors.forename: S
authors.initials: S
authors.lastname: Klashinsky
mesh_terms: D000416:Alberta / Q000453:epidemiology; D000821:Animal Feed / Q000382:microbiology; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000382:microbiology / Q000635:transmission*; D015169:Colony Count, Microbial; D004783:Environmental Microbiology; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D015995:Prevalence; D012621:Seasons; D013696:Temperature; D014871:Water Microbiology