title: Phylogenetic grouping and virulence potential of extended-spectrum-β-lactamase-producing Escherichia coli strains in cattle.
abstract: In line with recent reports of extended-spectrum beta-lactamases (ESBLs) in Escherichia coli isolates of highly virulent serotypes, such as O104:H4, we investigated the distribution of phylogroups (A, B1, B2, D) and virulence factor (VF)-encoding genes in 204 ESBL-producing E. coli isolates from diarrheic cattle. ESBL genes, VFs, and phylogroups were identified by PCR and a commercial DNA array (Alere, France). ESBL genes belonged mostly to the CTX-M-1 (65.7%) and CTX-M-9 (27.0%) groups, whereas those of the CTX-M-2 and TEM groups were much less represented (3.9% and 3.4%, respectively). One ESBL isolate was stx(1) and eae positive and belonged to a major enterohemorrhagic E. coli (EHEC) serotype (O111:H8). Two other isolates were eae positive but stx negative; one of these had serotype O26:H11. ESBL isolates belonged mainly to phylogroup A (55.4%) and, to lesser extents, to phylogroups D (25.5%) and B1 (15.6%), whereas B2 strains were quasi-absent (1/204). The number of VFs was significantly higher in phylogroup B1 than in phylogroups A (P = 0.04) and D (P = 0.02). Almost all of the VFs detected were found in CTX-M-1 isolates, whereas only 64.3% and 33.3% of them were found in CTX-M-9 and CTX-M-2 isolates, respectively. These results indicated that the widespread dissemination of the bla(CTX-M) genes within the E. coli population from cattle still spared the subpopulation of EHEC/Shiga-toxigenic E. coli (STEC) isolates. In contrast to other reports on non-ESBL-producing isolates from domestic animals, B1 was not the main phylogroup identified. However, B1 was found to be the most virulent phylogroup, suggesting host-specific distribution of virulence determinants among phylogenetic groups.
authors.affiliation: Unité Antibiorésistance et Virulence Bactériennes, ANSES Site de Lyon, France. charlotte.valat@anses.fr
authors.forename: Charlotte
authors.initials: C
authors.lastname: Valat
authors.forename: Frédéric
authors.initials: F
authors.lastname: Auvray
authors.forename: Karine
authors.initials: K
authors.lastname: Forest
authors.forename: Véronique
authors.initials: V
authors.lastname: Métayer
authors.forename: Emilie
authors.initials: E
authors.lastname: Gay
authors.forename: Carine
authors.initials: C
authors.lastname: Peytavin de Garam
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Madec
authors.forename: Marisa
authors.initials: M
authors.lastname: Haenni
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D016000:Cluster Analysis; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; 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; D005602:France; D014644:Genetic Variation; D005838:Genotype; D046228:Microarray Analysis; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors; D001618:beta-Lactamases