ABSTRACT
The hemolysin production of 19 strains of Streptococcus spp. isolated from pigs in the Jiangsu and Shanghai regions in recent years were examined. Eight isolates of Streptococcus suis type 2 from Jiangsu showed weak hemolysis on blood agar, but a stronger reaction in Todd-Hewitt broth(THB). The hemolysin belonged to the group of thiol-activated hemolysins. Nine strains of Streptoccus equi subsp. zooepidemicus showed strong hemolysis on blood agar and in THB containing 5% new-born calf serum, but no hemolysis in THB alone. This hemolysin was similar to streptolysin S(SLS). Another two isolates were atypical members of Lancefield group C Streptococcus and showed strong hemolysis on blood agar and in THB with 5% new-born calf serum, but the hemolysin was unlike either streptolysin O or SLS.