Methods: Saliva samples were obtained from 30 pairs of mother and child. The presence of SM was analysed in each of the 60 subjects by inoculation in culture medium (Mitis Salivarius Bacitracina Agar) and by PCR. Information was collected through surveys on several habits of mother and child and their DMFT Index was obtained by clinical examination. These data were then subjected to statistical analysis, both descriptively and crossed with the incidence of SM. The degree of relationship between the SM genotypes detected in mother and child was determined by genotyping methods.
Results: Isolation in culture media revealed an SM prevalence of 43.3% (n = 13) in mothers and 30% (n = 9) in children, and PCR revealed an SM prevalence of 63.3% (n = 19) in mothers and 56.7% (n = 17) in children. Inferential statistical analysis focused on the cross tabulation of the variables obtained from the clinical exam and questionnaire with the presence of SM revealed no statistical differences. PCR proved to be more sensitive than the isolation in culture media to analyse the prevalence of SM (p<0.05). Genotyping detected 6 different SM genotypes in 11 individuals. The presence of the same SM genotype between mother and child from the same pair was detected in 75% (3 out of 4) of the pairs studied.
Conclusions: PCR proved to be more sensitive than the isolation in culture media to analyse the prevalence of SM. Genotyping study revealed diversity of SM genotypes in the sample as well as a relatively high frequency of genotypic relationship between the SM detected in mother and her child.