title: A diagnostic strategy to determine the Shiga toxin-producing Escherichia coli O157 status of pens of feedlot cattle.
abstract: Although cattle are reservoirs, no validated method exists to monitor Shiga toxin-producing Escherichia coli O157 (STEC O157) on farms. In 29 Midwestern United States feedlot pens we compared culturing faeces from the individual cattle to: (1) culturing rope devices that cattle rub or chew; and (2) culturing a composite of faecal pats. Eighty-six per cent (68-96%) of pens were classified correctly using rope devices to detect pens with at least 16% of the cattle shedding STEC O157 [sensitivity=82% (57-96%); specificity=92% (62-100%)]. Ninety per cent of pens (73-98%) were classified correctly using composite faeces to detect pens with at least 37% of the cattle shedding STEC O157 [sensitivity=86% (42-100%); specificity=91% (71-99%)]. Ranking pens into three risk levels based on parallel interpretation of the pen-test results correlated (Spearman's r=0.76, P<0.0001) with the pen's prevalence. This strategy could identify pens of cattle posing a higher risk to food safety.
authors.affiliation: Department of Veterinary and Biomedical Sciences, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln, 68583-0907, USA.
authors.forename: D R
authors.initials: DR
authors.lastname: Smith
authors.forename: J T
authors.initials: JT
authors.lastname: Gray
authors.forename: R A
authors.initials: RA
authors.lastname: Moxley
authors.forename: S M
authors.initials: SM
authors.lastname: Younts-Dahl
authors.forename: M P
authors.initials: MP
authors.lastname: Blackford
authors.forename: S
authors.initials: S
authors.lastname: Hinkley
authors.forename: L L
authors.initials: LL
authors.lastname: Hungerford
authors.forename: C T
authors.initials: CT
authors.lastname: Milton
authors.forename: T J
authors.initials: TJ
authors.lastname: Klopfenstein
mesh_terms: D000818:Animals; D002417:Cattle / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000302:isolation & purification* / Q000472:pathogenicity; D012306:Risk; D022621:Shiga Toxin / Q000096:biosynthesis*
chemical_list: D022621:Shiga Toxin