title: Naturally acquired attaching and effacing Escherichia coli in sheep.
abstract: In a series of experiments involving the inoculation of sheep with Escherichia coli O157:H7, and subsequent detailed histopathological examination of the intestinal mucosa, attaching-effacing (AE) lesions formed by elements of the natural flora were observed in 18% of animals. These incidental AE lesions typically were small and sparse, and were not associated with clinical disease. It was possible to identify further some of the lesional bacteria, revealing that E. coli O115 had formed lesions in one of the seven affected animals, and similarly E. coli O26 had formed some of the lesions in another. As AE strains, source flocks, housing and feed sources were diverse, a common source of lesion-forming bacteria appears to be unlikely. It is postulated that subclinical AE lesions are a mechanism of persistence of AE bacteria in sheep.
authors.affiliation: Department of Clinical Veterinary Science, University of Bristol, Langford House, Avon BS40 5DU, UK.
authors.forename: A D
authors.initials: AD
authors.lastname: Wales
authors.forename: G R
authors.initials: GR
authors.lastname: Pearson
authors.forename: A
authors.initials: A
authors.lastname: Best
authors.forename: A L
authors.initials: AL
authors.lastname: Cookson
authors.forename: R M
authors.initials: RM
authors.lastname: La Ragione
authors.forename: J M
authors.initials: JM
authors.lastname: Roe
authors.forename: C M
authors.initials: CM
authors.lastname: Hayes
authors.forename: M J
authors.initials: MJ
authors.lastname: Woodward
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000907:Antibodies, Bacterial / Q000032:analysis; D003106:Colon / Q000382:microbiology / Q000473:pathology / Q000648:ultrastructure; D004927:Escherichia coli Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000254:growth & development*; D005243:Feces / Q000382:microbiology; D005260:Female; D007082:Ileum / Q000382:microbiology / Q000473:pathology / Q000648:ultrastructure; D007150:Immunohistochemistry / Q000662:veterinary; D007413:Intestinal Mucosa / Q000382:microbiology* / Q000473:pathology / Q000648:ultrastructure; D007841:Latex Fixation Tests / Q000662:veterinary; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology* / Q000473:pathology
chemical_list: D000907:Antibodies, Bacterial