Detection of Staphylococcus aureus in bovine mastitis and some characteristics with special reference to enterotoxin producibility and coagulase types of isolates

Characterization of Staphylococcus aureus strains isolated from bovine mastitis in Japan

Fifty-three strains of Staphylococcus aureus isolated from cows affected with mastitis from 21 prefectures in Japan were characterized by phenotypic and genotypic methods. Thirty-three (62.3%) strains showed biotype K-beta+CV:A, coagulase type VI, and sensitivity to bovine phages of group III or IV. These 33 strains could be subdivided into two groups on the basis of the production of staphylococcal enterotoxins (SEs) and on toxic shock syndrome toxin-1 (TSST-1). By pulsed-field gel electrophoresis, the 16 SEC- and TSST-1-producing strains showed similar patterns that differed by only a few fragments, suggesting that they were genetically closely related. Fifteen of 17 non SEC-producing strains which did not produce any other SEs and TSST-1 were genetically different from the SEC-producing strains and showed genetic diversity.

Coagulase typing of Staphylococcus aureus isolated from animals

Coagulase typing was performed on Staphylococcus aureus isolated from various animals. Of the 383 strains examined, 209 (54.6%) strains were typable and could be differentiated into 8 coagulase types. The remaining 174 strains were non-typable with antisera against the 8 known types of coagulases. This suggests that many strains of S. aureus of animal origin may possess unknown types of coagulases.