title: Antimicrobial resistance and genetic characteristics of Salmonella Typhimurium isolated from horses in Hokkaido, Japan.
abstract: In this study, we examined the antimicrobial susceptibility of 16 Salmonella Typhimurium isolates obtained from horses, and applied several genetic methods, namely polymerase chain reaction (PCR) for detecting class 1 integrons, multiplex PCR for detecting multidrug resistant S. Typhimurium definitive phage type 104 (MR-DT104), and fluorescent amplified-fragment length polymorphism (FAFLP). Seven isolates with an ampicillin, chloramphenicol, streptomycin, sulfonamide, and tetracycline (ACSSuT) type resistance pattern, harbored two class 1 integrons with sizes of 1.2 and 1.0 kb, and were identified as DT104 by bacteriophage typing. These isolates also showed a typical MR-DT104 amplification pattern, which was positive for flo(st), spvC, invA and int, in multiplex PCR. In the FAFLP analysis, the equine DT104 isolates and the previously reported ACSSuT-type resistant bovine isolates, which were also isolated in Hokkaido were included in the same genetic cluster. Our results retrospectively indicate that MR-DT104 infection has existed in horses in Japan at least since 1996, and it was suggested that there is a highly epidemiological relationship between the equine MR-DT104 isolates and certain multidrug resistant bovine isolates in the same area.
authors.affiliation: Equine Research Institute, Japan Racing Association, Tochigi, Japan. niwa@epizoo.equinst.go.jp
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Niwa
authors.forename: Toru
authors.initials: T
authors.lastname: Anzai
authors.forename: Hidemasa
authors.initials: H
authors.lastname: Izumiya
authors.forename: Tomoko
authors.initials: T
authors.lastname: Morita-Ishihara
authors.forename: Haruo
authors.initials: H
authors.lastname: Watanabe
authors.forename: Ikuo
authors.initials: I
authors.lastname: Uchida
authors.forename: Teruaki
authors.initials: T
authors.lastname: Tozaki
authors.forename: Seiji
authors.initials: S
authors.lastname: Hobo
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D001435:Bacteriophages / Q000235:genetics / Q000302:isolation & purification; D002417:Cattle; D017931:DNA Primers; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics; D006734:Horse Diseases / Q000382:microbiology*; D006736:Horses; D007564:Japan; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping; D012481:Salmonella Infections, Animal / Q000188:drug therapy / Q000235:genetics*; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D017931:DNA Primers; D004269:DNA, Bacterial