Characteristics of Streptococcus mutans Isolated from Human Dental Plaque and Blood

A comparison of physiological characteristics of Streptococcus mutans isolates from human blood (54 strains) and dental plaque (50 strains) showed that there were no appreciable differences among the strains. The species can be defined and differentiated by a combination of serological and physiological properties. The strains were tested for 30 physiological characteristics. Lancefield extracts of each strain were tested for precipitin reactions with antisera for Lancefield groups A, B, C, D, E, F, G, H, K, O, and A variant. The failure of Lancefield extracts of S. mutans to react with streptococcal group D antisera, the formation of characteristic gelatinous deposits in 5% sucrose broth, and acid formation in mannitol broth are the three major criteria for recognizing S. mutans.