title: Virulence genes in bla(CTX-M) Escherichia coli isolates from chickens and humans.
abstract: The aim of this study was to determine the presence of virulence genes in isolates of CTX-M Escherichia coli from diseased chickens, from healthy chickens and from urinary tract infections in people. Three CTX-M E. coli strains from three different instances of disease in poultry (two of which were E. coli related) were tested for bla(CTX-M) sequence type and replicon type. Additionally, they were tested for the presence of 56 virulence genes (encoding fimbriae, adhesins, toxins, microcins and iron acquisition genes) using a micro-array. Results were compared to the virulence genes present in isolates from 26 healthy chickens and from 10 people with urinary tract infections. All genes found in isolates from diseased birds, including the astA (heat stable toxin) and tsh (temperature sensitive haemagglutinin) genes which have previously been associated with colibacillosis in chickens, were also present in isolates from healthy birds. However, 6/10 of the virulence genes found were exclusive to isolates from humans. Genes exclusive to chicken isolates included ireA (sidephore receptor), lpfA (long polar fimbriae), mchF (microcin transporter protein) and tsh whilst genes exclusive to human isolates included ctdB (cytolethal distending toxin), nfaE (non-fimbrial adhesion), senB (plasmid encoded enterotoxin) and toxB (toxin B). The results support previous findings that CTX-M E. coli strains in chickens are generally different from those causing disease in humans, but genes such as astA and tsh in isolates from diseased birds with colisepticaemia were also present in isolates from healthy birds.
authors.affiliation: Veterinary Laboratories Agency (Weybridge), Department of Bacteriology, New Haw, Addlestone, Surrey KT15 3NB, United Kingdom. l.randall@vla.defra.gsi.gov.uk
authors.forename: Luke
authors.initials: L
authors.lastname: Randall
authors.forename: Guanghui
authors.initials: G
authors.lastname: Wu
authors.forename: Neil
authors.initials: N
authors.lastname: Phillips
authors.forename: Nick
authors.initials: N
authors.lastname: Coldham
authors.forename: Dik
authors.initials: D
authors.lastname: Mevius
authors.forename: Chris
authors.initials: C
authors.lastname: Teale
mesh_terms: D000818:Animals; D002645:Chickens / Q000382:microbiology*; D004926:Escherichia coli / Q000235:genetics* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000662:veterinary; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis / Q000662:veterinary; D011201:Poultry Diseases / Q000382:microbiology*; D014551:Urinary Tract / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D037521:Virulence Factors; D001618:beta-Lactamases