The differentiation of the lactic streptococci and their antibiotics

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