Factors Necessary for Massive Growth of Group A Hemolytic Streptococcus

Abstract

A study has been made of the factors necessary for the massive growth of Group A streptococci (Streptococcus pyogenes) in a chemically defined, fluid medium. The medium consisted of a complete acid hydrolysate of casein supplemented with cystine, tryptophane and glutamine, together with glucose, salts and certain accessory growth factors. The following were found to be among the principal factors which permitted growth equivalent to 250 mg. of streptococcal N per liter: (a) Suitable concs. of casein hydrolysate, glucose, glutamine and pantothenic acid; (b) Reduction in total salt conc. to a minimum; (c) Frequent neutralization of lactic acid formed during growth. Although specifically developed for the C203S strain, the medium gave high yields of other Group A streptococci, namely strains NY#5, 1048M, 1840M and 594B.