title: Antimicrobial resistance types and genes in Salmonella enterica infantis isolates from retail raw chicken meat and broiler chickens on farms.
abstract: Salmonella enterica subsp. enterica serotype Infantis isolates from retail raw chicken meat (n = 98) and broiler chickens on farms (n = 70) were examined for antimicrobial susceptibility and antimicrobial resistance genes. A total of 15 antimicrobial resistance types, 14 in meat and 10 in broiler isolates, were identified, and 9 of the 15 types were indistinguishable between meat and broiler isolates. Resistance to both oxytetracycline and dihydrostreptomycin accounted for 94.0% of the resistance types in meat and broiler isolates, and each type harbored aadA1 within 1.0 kb of class 1 integron and tetA. Of nalidixic acid resistance types, point mutations at 87Asp (GAC) to Tyr (TAC) in the quinolone resistance-determining region of gyrA was detected in 10 of 13 meat isolates and at 87Asp to Asn (AAC) in four of seven broiler isolates. These findings suggest that the antimicrobial resistance of Salmonella Infantis in retail chicken meat predominantly originates from broiler chickens.
authors.affiliation: National Veterinary Assay Laboratory, Ministry of Agriculture, Forestry and Fisheries, 1-15-1 Tokura, Kokubunji, Tokyo 185-8511, Japan. asai-t@nval.go.jp
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Asai
authors.forename: Michiyo
authors.initials: M
authors.lastname: Itagaki
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Shiroki
authors.forename: Makiko
authors.initials: M
authors.lastname: Yamada
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Tokoro
authors.forename: Akemi
authors.initials: A
authors.lastname: Kojima
authors.forename: Kanako
authors.initials: K
authors.lastname: Ishihara
authors.forename: Hidetake
authors.initials: H
authors.lastname: Esaki
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tamura
authors.forename: Toshio
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens / Q000382:microbiology*; D003257:Consumer Product Safety; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D006801:Humans; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D012703:Serotyping
chemical_list: D000900:Anti-Bacterial Agents