Characterization and identification of streptococci isolated from bovine mammary glands.

A total of 317 gram-positive, catalase-negative cocci isolated from bovine mammary glands were characterized and identified using current species descriptions. Two hundred eighty-seven isolates (90.5%) could be placed in 11 distinct species. Streptococcus uberis was the most frequently encountered species and could be separated into two previously described genetic types based upon sucrose utilization. Streptococcus dysgalactiae and a newly described species, Streptococcus saccharolyticus, were the most frequently isolated organisms from teat canal swabs. Thirty isolates could not be placed in currently described species. A proposed identification scheme based upon serological grouping and seven biochemical tests would permit 24 h identification of streptococci isolated from bovine mammary glands.