title: Virulence properties and attaching-effacing activity of Escherichia coli O45 from swine postweaning diarrhea.
abstract: Escherichia coli O45 isolates associated with swine postweaning diarrhea in Québec were characterized with respect to virulence determinants genetically and investigated for their attaching and effacing (A/E) activities by experimental inoculation of gnotobiotic piglets and by the HEp-2 cell adherence assay. All of 32 isolates tested were negative for enterotoxigenic and verotoxigenic E. coli virulence determinants, heat-labile enterotoxin (LT), heat-stable enterotoxins (STap, STb), verotoxins (VT1, VT2), and F4 (K88), F5 (K99), F6 (987P), and F41, except one STb-positive and two F4-positive isolates. A total of 25 isolates hybridized with an EaeA probe, and 11 hybridized with an enteropathogenic E. coli adherence factor (EAF) probe. None of 32 isolates hybridized with a bundle-forming pilus (BFP) probe. The EAF, EaeA, and BFP factors have been associated with human enteropathogenic E. coli strains. A total of 10 of 12 eaeA-positive porcine O45 isolates induced A/E lesions characterized by intimate adherence of bacteria to the intestinal epithelial cell membrane with effacement of the microvilli, similar to those of human attaching-effacing E. coli. However, A/E lesions were not observed in the piglets inoculated with any one of three eaeA-negative O45 isolates. All E. coli O45 isolates were non-adherent to HEp-2 cells. Thus, we have demonstrated the production of typical A/E lesions by nonenterotoxigenic E. coli O45 isolates from swine postweaning diarrhea. The results indicate the significance of the eaeA gene in A/E activities of these isolates and suggest that EAF and BFP are not involved in O45 E. coli infection of weaning piglets.
authors.affiliation: Groupe de Recherche sur les Maladies Infectieuses du Porc, Université de Montréal, Faculté de Médecine Vétérinaire, Saint-Hyacinthe, Québec, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Zhu
authors.forename: J
authors.initials: J
authors.lastname: Harel
authors.forename: M
authors.initials: M
authors.lastname: Jacques
authors.forename: C
authors.initials: C
authors.lastname: Desautels
authors.forename: M S
authors.initials: MS
authors.lastname: Donnenberg
authors.forename: M
authors.initials: M
authors.lastname: Beaudry
authors.forename: J M
authors.initials: JM
authors.lastname: Fairbrother
mesh_terms: D018829:Adhesins, Bacterial; D000818:Animals; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D002352:Carrier Proteins; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology*; D014774:Virulence; D014886:Weaning
chemical_list: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C073819:eaeA protein, E coli