Bacteriocine Production by Group a Streptococci

I t has been known for many years t ha t some strains of Escherichia coli, Bacillus megaterium, and Group D streptococci secrete substances called colicines, or bacteriocines, which inhibi t the growth of o ther strains of closely related microorganisms (1-6). In 1949 Sherwood and his coworkers (7) reported observations on the inhibitory action of certain strains of be ta hemolyt ic streptococci on other strains of streptococci. Seventeen of 61 strains of be ta hemolyt ic streptococci inhibi ted the growth of one or more strains of Group A and non-Group A streptococci. Five of 29 strains of Group A streptococci had this inhibi tory effect, but the serologic types of these strains were not s tated. In this paper the inhibi tory action of Group A streptococci on other strains of Group A and non-Group A streptococci was investigated. I t was found tha t these inhibi tory substances are produced more frequently by the nephritogenic types than by other serologic types of Group A streptococci.