First characterization and emergence of SHV-60 in raw milk of a healthy cow in Japan.

During monitoring of raw milk samples from healthy cows for the presence of antibiotic resistant bacteria, one isolate of Klebsiella pneumoniae strain HUF-100 was found to be resistant to oxyimino-cephalosporins and aztreonam. It was found to carry a chromosomally-encoded extended-spectrum beta-lactamase that has not been described previously, namely SHV-60. Thus, it must be expected that this strain will spread further among food-producing animals and thereby constitute a reservoir of this resistant strain and resistance gene that can transfer to and cause treatment problems for humans. The present study confirms the hypothesis that some of novel multiple antibiotic resistant zoonotic bacterial pathogens may initially emerge from food animals and reports, for the first time, this type of emergence in Japan.