title: Presence and characterization of extraintestinal pathogenic Escherichia coli virulence genes in F165-positive E. coli strains isolated from diseased calves and pigs.
abstract: The virulence genotype profile and presence of a pathogenicity island(s) (PAI) were studied in 18 strains of F165-positive Escherichia coli originally isolated from diseased calves or piglets. On the basis of their adhesion phenotypes and genotypes, these extraintestinal pathogenic strains were classified into three groups. The F165 fimbrial complex consists of at least two serologically and genetically distinct fimbriae: F165(1) and F165(2). F165(1) is encoded by the foo operon (pap-like), and F165(2) is encoded by fot (sfa related). Strains in group 1 were foo and fot positive, strains in group 2 were foo and afa positive, and strains in group 3 were foo positive only. The strains were tested for the presence of virulence genes found mainly in extraintestinal pathogenic E. coli (ExPEC) strains. Although all the strains were positive for the papA variant encoding F11 fimbriae incD, traT, and papC, the prevalence of virulence genes commonly found in PAIs associated with ExPEC strains was highly variable, with strains of group 2 harboring most of the virulence genes tested. papG allele III was detected in all strains in group 1 and in one strain in group 3. All other strains were negative for the known alleles encoding PapG adhesins. The association of virulence genes with tRNA genes was characterized in these strains by using pulsed-field gel electrophoresis and DNA hybridization. The insertion site of the foo operon was found at the pheU tRNA locus in 16 of the 18 strains and at the selC tRNA locus in the other 2 strains. Furthermore, 8 of the 18 strains harbored a high-pathogenicity island which was inserted in either the asnT or the asnV/U tRNA locus. These results suggest the presence of one or more PAIs in septicemic strains from animals and the association of the foo operon with at least one of these islands. F165-positive strains share certain virulence traits with ExPEC, and most of them are pathogenic in piglets, as tested in experimental infections.
authors.affiliation: Groupe de Recherche sur les Maladies Infectieuses du Porc, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Canada.
authors.forename: Hojabr
authors.initials: H
authors.lastname: Dezfulian
authors.forename: Isabelle
authors.initials: I
authors.lastname: Batisson
authors.forename: John M
authors.initials: JM
authors.lastname: Fairbrother
authors.forename: Peter C K
authors.initials: PC
authors.lastname: Lau
authors.forename: Atef
authors.initials: A
authors.lastname: Nassar
authors.forename: George
authors.initials: G
authors.lastname: Szatmari
authors.forename: Josée
authors.initials: J
authors.lastname: Harel
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics* / Q000378:metabolism; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D036781:Fimbriae Proteins / Q000235:genetics* / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000235:genetics; D007422:Intestines / Q000382:microbiology; D009876:Operon; D010802:Phylogeny; D012343:RNA, Transfer / Q000235:genetics; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology*; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D029968:Escherichia coli Proteins; C088773:F165 protein, E coli; D037521:Virulence Factors; D036781:Fimbriae Proteins; D012343:RNA, Transfer