Relatedness and classification of Streptococcus mutans and "mutans-like" streptococci.

The "mutans-like" streptococci can be separated into five species (Streptococcus mutans, S. rattus, S. sobrinus, S. cricetus, and S. ferus) that belong to the same rRNA homology cluster. New valuable chemical characters for differentiation of the five species--such as peptidoglycan type, presence of cell wall teichoic acid, and cell wall sugar composition--are described. The peptidoglycan type and the cell wall sugar composition can be determined by rapid procedures.