445. The differentiation of the lactic streptococci and their antibiotics

Twenty-three strains of lactic acid streptococci were shown to be types of Streptococcus cremoris or Str. lactis by cultural, biochemical and serological means. The antibiotics produced by the cremoris strains could be differentiated readily from the lactis antibiotics, of which at least five different varieties are described. A cross-test and a resistant-strain test were used to differentiate the antibiotics.