Polysaccharase activity in Streptococcus agalactiae (group B streptococci)

Of 300 recently isolated strains of Streptococcus agalactiae from human sources, 97% degraded starch. Representative strains also degraded glycogen, pullulan, amylopectin and amylose. The polysaccharase activity is easily detected by clearing around growth on Columbia agar base medium. The activity is weaker than that of some S. pyogenes strains, and it does not appear to produce fermentable products but is inhibited by the presence of easily used sugars.