Peptococcus (S. Micrococcus) indolicus. The demonstration of two varieties of hemolysin forming strains.

On the basis of biochemical and serological criteria 2 hemolysin forming varieties of peptococci were identified as Peptococcus indolicus. Of a total of 16 hemolytic strains examined 9 originated from the vagina of clinically healthy cows, 4 from mastitis secretions from dry cows, 2 from the interdigital skin of clinically healthy sows, and 1 from a subcutaneous abscess in a pig. Two strains were designated a-hemolytic and 14 β-hemolytic. On blood agar plates colonies of the α-hemolytic variety were surrounded by narrow zones of almost complete hemolysis, while colonies of the β-hemolytic variety were surrounded by broad zones of incomplete hemolysis. The hemolysins were termed α- and β-hemolysin, respectively. The β-hemolysin, but not the α-hemolysin, could be demonstrated in cultures grown in liquid media. The β-hemolysin was found to be filtrable, relatively thermoresistant, and non-dermonecrotic. By gel diffusion analyses the 2 α-hemolytic strains were referred to Serotype C. Ten of the β-hemolytic strains belonged to Serotype C, 2 to Type B, 1 to Type D, and 1 to Type E.