The aim of this study was to determine the prevalence of species of the mutans group in samples of non-stimulated saliva from 50 children and their mothers. Aliquots of pure saliva were submitted to seriate decimal dilution, plated with the aid of the L glass rod onto SB20 modified medium, and incubated in a candle jar for 72 hours at 37ºC. After the count of the cfu of the mutans group, the characteristic colonies were transferred to thioglycolatte medium, incubated for 24hours at 37ºC and submitted to a biochemical identification scheme. Streptococci of the mutans group were detected in the saliva of 47 (94.0%) children, and in 50 (100.0%) mothers. S. mutans and S. sobrinus were detected in 15 (30.0%) children, and in 24 (48.0%) mothers who were multicolonized, with the cfu number corresponding to 1.28 x 106 and 3.57 x 106, respectively. The same species of the mutans group were harbored by 31 (62.0%) mother-child pairs.
Mutans streptococci; Biotypes; Prevalence; cfu/ml saliva
