The prevalence of Shiga-toxigenic Escherichia coli (STEC) in Japan was examined using rectal/stool samples obtained from 932 healthy dairy cows from 123 farms in 11 prefectures between 2006 and 2007. Screening with stx-polymerase chain reaction (PCR) revealed a prevalence of 30.4% (283 animals). STEC strains were isolated from 111 animals. Although 8 O-serogroups (O8, O26, O84, O103, O111, O113, O116, and O136) comprised the majority of O-serogroups in healthy dairy cows in Japan in 1998, half of the 118 selected STEC strains were serotyped as O2, O8, O26, O153, or O117 in this study. Twenty-eight of the 118 STEC strains (24%) showed resistance to some conventional drugs such as dihydrostreptomycin, oxytetracycline, and aminobenzylpenicillin. Although the prevalence of STEC in cows decreased from 17% to 12%, the antimicrobial resistance ratio increased from 8.7% to 24% in the past decade in Japan.
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Reference:
Kobayashi, H. et al. (2009) J. Vet. Med. Sci. 71(3):363-366.
