[The occurrence of Streptococcus mutans variants in man and laboratory animals].

Numerous S. mutans strains isolated from human dental plaque and from that of rats and hamsters were classified by a well-known biochemical differentiation system for the separation of the serotypes "a to e", and by seven different biotypes (I-VII). 182 S. mutans strains from human plaque were assigned to the following serotypes: "c" = 68%, "d" = 19%, and "b" and "e" = 4% each. Serotype "a" was not found at all and 10 strains could not be classified. Out of 60 S. mutans strains from the oral cavity of rats, 85% belonged to serotype "c", while in 25 strains from hamsters serotypes "e" and "d" predominated.