Susceptibilities of Corynebacterium bovis and Corynebacterium amylocolatum isolates from bovine mammary glands to 15 antimicrobial agents.

Coryneform bacteria are frequently isolated from bovine mastitis and are associated with economic losses. Generally, the MICs of the 15 antimicrobial agents tested at which 90% of the isolates tested are inhibited for 46 Corynebacterium bovis and 13 Corynebacterium amylocolatum strains were low. These are the first quantitative antimicrobial susceptibility data available for coryneforms from bovine mastitis. Data from this study suggest that comparable corynebacteria from humans have a much higher level of antimicrobial resistance to a variety of antimicrobial agents.