title: Isolation from a sheep of an attaching and effacing Escherichia coli O115:H- with a novel combination of virulence factors.
abstract: Attaching and effacing (AE) lesions were observed in the caecum, proximal colon and rectum of one of four lambs experimentally inoculated at 6 weeks of age with Escherichia coli O157:H7. However, the attached bacteria did not immunostain with O157-specific antiserum. Subsequent bacteriological analysis of samples from this animal yielded two E. coli O115:H(-) strains, one from the colon (CO) and one from the rectum (RC), and those bacteria forming the AE lesions were shown to be of the O115 serogroup by immunostaining. The O115:H(-)isolates formed microcolonies and attaching and effacing lesions, as demonstrated by the fluorescence actin staining test, on HEp-2 tissue culture cells. Both isolates were confirmed by PCR to encode the epsilon (epsilon) subtype of intimin. Supernates of both O115:H(-) isolates induced cytopathic effects on Vero cell monolayers, and PCR analysis verified that both isolates encoded EAST1, CNF1 and CNF2 toxins but not Shiga-like toxins. Both isolates harboured similar sized plasmids but PCR analysis indicated that only one of the O115:H(-) isolates (CO) possessed the plasmid-associated virulence determinants ehxA and etpD. Neither strain possessed the espP, katP or bfpA plasmid-associated virulence determinants. These E. coli O115:H(-) strains exhibited a novel combination of virulence determinants and are the first isolates found to possess both CNF1 and CNF2.
authors.affiliation: *Department of Bacterial Diseases, Veterinary Laboratories Agency (Weybridge), Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, †Department of Clinical Veterinary Science and ‡Department of Pathology and Microbiology, University of Bristol, Langford, Bristol BS40 3DU.
authors.forename: Adrian L
authors.initials: AL
authors.lastname: Cookson
authors.affiliation: *Department of Bacterial Diseases, Veterinary Laboratories Agency (Weybridge), Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, †Department of Clinical Veterinary Science and ‡Department of Pathology and Microbiology, University of Bristol, Langford, Bristol BS40 3DU.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Hayes
authors.affiliation: *Department of Bacterial Diseases, Veterinary Laboratories Agency (Weybridge), Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, †Department of Clinical Veterinary Science and ‡Department of Pathology and Microbiology, University of Bristol, Langford, Bristol BS40 3DU.
authors.forename: Geoffrey R
authors.initials: GR
authors.lastname: Pearson
authors.affiliation: *Department of Bacterial Diseases, Veterinary Laboratories Agency (Weybridge), Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, †Department of Clinical Veterinary Science and ‡Department of Pathology and Microbiology, University of Bristol, Langford, Bristol BS40 3DU.
authors.forename: John M
authors.initials: JM
authors.lastname: Roe
authors.affiliation: *Department of Bacterial Diseases, Veterinary Laboratories Agency (Weybridge), Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, †Department of Clinical Veterinary Science and ‡Department of Pathology and Microbiology, University of Bristol, Langford, Bristol BS40 3DU.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Wales
authors.affiliation: *Department of Bacterial Diseases, Veterinary Laboratories Agency (Weybridge), Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB, †Department of Clinical Veterinary Science and ‡Department of Pathology and Microbiology, University of Bristol, Langford, Bristol BS40 3DU.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Woodward
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D000818:Animals; D001422:Bacterial Adhesion; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics; D003106:Colon / Q000382:microbiology / Q000473:pathology / Q000648:ultrastructure; D046508:Culture Techniques; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D029968:Escherichia coli Proteins; D005838:Genotype; D008854:Microscopy, Electron / Q000662:veterinary; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012007:Rectum / Q000382:microbiology / Q000473:pathology / Q000648:ultrastructure; D012703:Serotyping / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology*; D014774:Virulence
chemical_list: D018829:Adhesins, Bacterial; D001427:Bacterial Toxins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C073819:eaeA protein, E coli