A taxonomic study of some strains of streptococci which grow at 10 °C but not at 45 °C including Streptococcus lactis and Streptococcus cremoris

Physiological properties, properties of their lactate dehydrogenases and DNA /DNA relatedness have been determined for strains of streptococci which grow at 10°C but not at 45 °C; these include strains of Streptococcus lactis, Streptococcus cremoris and Streptococcus raffinolactis. The results show that S. lactis and S. cremoris are variants of a single species unrelated to S. raffinolactis and also to a group of strains which cannot be separated from S. lactis on easily determined physiological properties.

Several strains could not be classified but one strain received as Lactobacillus hordniae proved to be a variant of S. lactis by DNA/DNA homology and the properties of its lactate dehydrogenase, although its physiological properties would not indicate that it belongs to that species.