2009 年 71 巻 8 号 p. 1115-1119
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 flost, 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.
