Prevalence and characterization ofStaphylococcus aureusisolated in raw milk from cows in Hokkaido, Japan

摘要

The aim of this study was to characterize the phenotypes and genotypes ofStaphylococcus aureusisolated from raw bovine milk in Hokkaido, Japan.S. aureusisolates were identified in 135 of 436 milk samples from cows with and without signs of mastitis from three farms in Hokkaido. These clinical isolates were characterized for antimicrobial susceptibility patterns, molecular typing using phage-open-reading frame typing (POT), coagulase gene type, virulence genes, and biofilm-associated genes and were evaluated for biofilm-forming ability. Most isolates were susceptible to the antimicrobial agents tested. The highest rate of resistance was to ampicillin. Molecular typing of allS. aureusisolates indicated a predominance of coagulase type VI and 0-17-34 POT type, and virulence genes were highly prevalent in the isolates from all farms. Moreover, a high percentage of the 0-17-34 POT type isolates showed extensive formation of biofilm. These findings will help veterinarians and farmers to understand the epidemiology ofS. aureusso that they can monitor the transmission and spread of this pathogen and control it more effectively.