Detection and characterization of hemolysin production in Streptococcus mutans.

Beta-hemolytic strains of Streptococcus mutans were identified and physiological reactions and hemolysin production were studied. Strict anaerobic conditions were shown to be indispensable for the expression of beta-hemolysis on blood agar plates; hemolysis was only observed after growth in an atmosphere with an oxygen content of 10 ppm or lower. The occurrence of beta-hemolytic strains was found not to be restricted to one biotype of S. mutans. Two hemolytic activities were detected in liquid cultures. Oxygen-labile activity was detected in prereduced broth cultures and was shown to be unstable and indetectable in supernatants. Solubilization of oxygen-labile hemolysin was achieved by the addition of Tween 80 to the cultures. Oxygen-stable activity was detected in supernatants of cell suspensions in the presence of maltose, Casamino Acids, and Tween 80. In contrast to oxygen-labile activity, oxygen-stable activity was not detected in broth cultures.