Isolation of Meticillin-resistant Staphylococcus Aureus (MRSA) from Swine in Japan

Meticillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 398 is widely prevalent in swine in Europe and North America. To determine the prevalence of MRSA, and specifically ST398, in Japanese swine, a total of 115 nasal swabs and 115 faecal samples from swine reared at 23 farms located in eastern Japan were investigated. MRSA was isolated from a nasal sample (0.9%) but not from any faecal samples. The strain of MRSA was classified as ST221 by multilocus sequence typing and as t002 by spa typing. The MRSA isolate exhibited resistance to ampicillin, meticillin and dihydrostreptomycin. Interestingly, it remained susceptible to cefazolin, ceftiofur, imipenem, gentamicin, kanamycin, chloramphenicol, oxytetracycline, erythromycin, azithromycin, tylosin, vancomycin, enrofloxacin and trimethoprim. The prevalence of MRSA amongst swine was low and MRSA ST398 was not recovered in the present study.