Abstract
During the period from november, 1979 to August, 1980, 332 samples of mastitis udders of cattle killed at the Tokyo Shibaura Slaughter House were investigated for the presence of Staphylococcus aureus. The isolates were tested for biochemical characteristics, enterotoxin production and coagulase typing. Eighty-seven S. aureus were isolated from the 85(25.6%) samples of 332 mastitis udders examined. Twenty-nine(33.3%) of the 87 strains produced enterotoxins A, B or C, and 24(82.8%) of them produced enterotoxin C. All except one strain, fell into either of types I through VIII in coagulase typing. Types VI(34.5%) and V(20.7%) were dominant among the eight coagulase types. Of the 87 strains 49(56.3%) coagulated bovine plasma irrespective of 100% in rabbit plasma coagulation. Twenty-nine(33.3%) isolates produced fibrinolysin, 82(94.3%) fermented mannitol, 40(46.0%) were positive in egg-yolk reaction, and all the strains grew on blood agar containing 1:200, 000 crystal violet showing the A type colonial character. Some of the staphylococal strains of bovine origin were negative in bovine plasma coagulation test, but positive in fibrinolysin. It is suggested from these results that S. aureus of bovine origin might be one of the causative agents for food poisoning.
