Sub-Divisions within the Genus Streptococcus Using Deoxyribonucleic Acid/Ribosomal Ribonucleic Acid Hybridization

A preliminary classification of strains from several species of streptococci by DNA/rRNA hybridization showed several sub-groups. The largest sub-group divided into two clusters (1) included S. bovis, S. uberis and S. salivarius and (2) S. agalactiae, S. dysgalactiae, S. acidominimus and S. thermophilus. S. lactis and S. cremoris formed a different sub-group as did S. faecalis and S. faecium, S. raffinolactis and most species of viridans streptococci did not associate with any of the sub-groups. The technique was of assistance in linking strains with unusual phenotypic properties to named species.