Gangrenous mastitis associated with Streptococcus gallolyticus subsp. gallolyticus in Japanese Black Cattle

Abstract

A four-year-old breeding head of Japanese Black Cattle showed swollen and palpable induration in its left rear quarter, which was diagnosed as gangrenous mastitis, in Ishigaki, Okinawa Prefecture, Japan, in 2012. An alpha-hemolytic gram-positive coccus was isolated from milk samples from the head of cattle with a titer of 1.4×10⁵ CFU/ml. The isolate was identified as Streptococcus gallolyticus using an API Strep kit and PCR targeting sodA. Furthermore, it was found to belong to S. gallolyticus subsp. gallolyticus (S. g. g.) based on the degrading activities of tannate and gallate. Antibiotic susceptibility tests showed that the isolate was highly susceptible to penicillins and cephems, whereas it was resistant to aminoglycosides and macrolides. We here report the first case of Japanese Black Cattle mastitis associated with S. g. g. in Japan.