title: Genotype comparison of sorbitol-negative Escherichia coli isolates from healthy broiler chickens from different commercial farms.
abstract: Hybridization on arrays was used to assess the presence of virulence-associated genes and to determine the relatedness of 32 non-O157 sorbitol-negative Escherichia coli isolates from healthy broiler chickens. These isolates were from commercial farms that used feed supplemented with different antimicrobial agents (virginiamycin, bacitracin, salinomycin, narasin, nicarbazin, or diclazuril). For each isolate, fluorescent probes were made from genomic DNA and were hybridized on DNA arrays composed of genes associated with general functions, virulence, iron uptake systems, and DNA repair genes (e.g., mut genes). Hybridization on arrays results showed that isolates from the same farm tended to be clustered but actually represented 18 genetically distinct groups of isolates. Results revealed that some isolates showed similarity to human uropathogenic E. coli or avian pathogenic E. coli. Four avian pathogenic E. coli-like isolates were detected. Another isolate possessed the intimin gene (eaeA) and typical genes of the type 3 secretion system associated with enteropathogenic E. coli and enterohemorrhagic E. coli strains. Genes from a second system (secondary type 3 secretion system) homologous to that found in Salmonella Typhimurium were detected in many isolates. Several of the studied isolates also possessed the aerobactin, salmochelin, and yersiniabactin genes involved in iron acquisition in pathogenic bacteria. Our results clearly suggest that commensal E. coli isolates from chickens are reservoirs of virulence-associated genes and may represent colibacillosis and zoonotic risks.
authors.affiliation: Centre d'Etude et de Valorisation de la Diversité Microbienne (CEVDM), Département de Biologie, Faculté des Sciences, Université de Sherbrooke, 2500 Boulevard de Université, Sherbrooke, Québec, Canada, J1K 2R1.
authors.forename: B
authors.initials: B
authors.lastname: Lefebvre
authors.forename: M
authors.initials: M
authors.lastname: Gattuso
authors.forename: H
authors.initials: H
authors.lastname: Moisan
authors.forename: F
authors.initials: F
authors.lastname: Malouin
authors.forename: M S
authors.initials: MS
authors.lastname: Diarra
mesh_terms: D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002645:Chickens / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity*; D020869:Gene Expression Profiling; D005838:Genotype; D007501:Iron / Q000378:metabolism; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics; D011110:Polymorphism, Genetic; D013012:Sorbitol / Q000378:metabolism*; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D013012:Sorbitol; D007501:Iron