511. Observations on the serological typing of group N (‘lactic’) streptococci

Abstract

1. Agglutinating type sera were prepared in rabbits for fourteen representative strains in a collection of sixty-eight group N (‘lactic’) streptococci.2. Common type antigens, distinct for each named species, were found in strains ofStr. lactis(inhibitory varieties),Str. diacetilactisandStr. cremoris.3. Certain individuals in each of the named ‘groups’ contained additional heterologous antigens, some of which were identical to heterologous (but not the common) antigens in strains of other groups.4. Quantitative differences in the representation of common antigens were also found.5.Str. lactisOJ andStr. cremorisHP were shown to be mirror images of each other so far as their type antigens are concerned, containing two common type antigens in inverse proportions of 4:1 respectively.Str. lactisOJ possesses the ‘cremoris group’ type antigen, and the implications of this observation are discussed.