title: Evaluation of dietary influences on Escherichia coli O157:H7 shedding by sheep.
abstract: The effect of diet, an abrupt diet change, and fasting on the shedding of Escherichia coli O157:H7 was investigated with experimentally inoculated sheep as a ruminant model. Sheep were fed a grass hay diet (G), which was low in protein and digestible energy and high in fiber, or a mixture of corn and pelleted alfalfa (C), which was high in protein and digestible energy and low in fiber. After a single oral inoculation of E. coli O157:H7, all the animals shed fecal E. coli O157:H7. However, sheep that were fed G shed the bacterium almost twice as long as, and in larger numbers than, did sheep that were fed C. The number of culture-positive animals increased after the diet was abruptly changed from C to G and decreased with the opposite change (G to C). A 24-h fast did not influence E. coli O157:H7 shedding. Horizontal transmission of infection between animals occurred. Recent shedding of E. coli O157:H7 did not affect recolonization with E. coli O157:H7. The findings presented in this study indicate that preharvest control of diet may reduce the risk of E. coli O157:H7-positive animals entering the food chain.
authors.affiliation: Department of Microbiology, Molecular Biology, and Biochemistry, University of Idaho, Moscow 83844, USA.
authors.forename: I T
authors.initials: IT
authors.lastname: Kudva
authors.forename: C W
authors.initials: CW
authors.lastname: Hunt
authors.forename: C J
authors.initials: CJ
authors.lastname: Williams
authors.forename: U M
authors.initials: UM
authors.lastname: Nance
authors.forename: C J
authors.initials: CJ
authors.lastname: Hovde
mesh_terms: D000821:Animal Feed; D000818:Animals; D001431:Bacteriological Techniques; D004032:Diet; D004927:Escherichia coli Infections / Q000517:prevention & control / Q000635:transmission / Q000662:veterinary; D019453:Escherichia coli O157 / Q000302:isolation & purification* / Q000472:pathogenicity; D005215:Fasting; D005243:Feces / Q000382:microbiology; D005260:Female; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000517:prevention & control; D006801:Humans; D012756:Sheep / Q000382:microbiology*; D012757:Sheep Diseases / Q000382:microbiology / Q000517:prevention & control / Q000635:transmission; D014868:Water Deprivation