Effect of glucose and sucrose on survival in batch culture of Streptococcus mutans C67-1 and a noncariogenic mutant, C67-25.

The growth and survival of two strains of Streptococcus mutans in 5% (wt/vol) glucose or sucrose broth was investigated. S. mutans strain C67-1 showed little loss of viability after 30 h of incubation in batch culture in the presence of either sugar. S. mutans strain C67-25, a noncariogenic mutant of C67-1 that has lost the ability of the latter to produce sticky, insoluble extracellular polysaccharide when grown in sucrose broth, showed a dramatic loss of viability after 30 h of incubation in either glucose or sucrose broth, the effect being most marked in the presence of glucose. The loss of viability was shown to be due to acid production. Insoluble extracellular polysaccharide production appears to be a phenomenon favoring the survival of organisms subjected to high sucrose levels. Other factors must be involved, however, since there are differences between the two strains as regards their survival in glucose broth.