Taxonomic Studies on Streptococci of Serological Groups C, G and L and Possibly Related Taxa

Summary The taxonomic relationships among selected species of ‘pyogenic’ and ‘viridans’ streptococci were examined using DNA-DNA hybridization, DNA base composition and biochemical tests. The results of the present study indicate that Streptococcus dysgalactiae, S. equisimilis and streptococci of Lancefield serological groups C, G and L are a single species. Strains of S. equi and “S. zooepidemicus” were found to be closely related on the basis of DNA-DNA hybridizations. It is suggested that “S. zooepidemicus” be reclassified as S. equi subsp. zooepidemicus nom. rev., comb. nov. and an emended description of the species S. dysgalactiae is given.