Intraspecies variations in nutritionally variant streptococci: rRNA gene restriction patterns of Streptococcus defectivus and Streptococcus adjacens.

The rRNA gene restriction patterns of two species of nutritionally variant streptococci, Streptococcus defectivus and Streptococcus adjacens, were determined, and the results were compared with the electrophoretic migration profiles of penicillin-binding proteins. Reference strains belonging to various streptococcal species were used as controls. Our results correlated with the results of DNA-DNA hybridization experiments and confirmed the delineation of these two species. Moreover, they demonstrated that intraspecies variations occur and suggested that there are two subspecies of S. defectivus.