Genotypic diversity and acidogenicity of Streptococcus mutans in Down syndrome children

Aims:To evaluate the genotypic diversity and acidogenicity ofStreptococcus mutans(S. mutans) and the potential association of these factors with dental caries experiencein children with DS compared to non-DS children (controls).Methods and results:Seventeen children (age 6-12 years) with high salivaryS.mutanscounts (>2.5×105CFU/mL) were selected and divided into two groups: DSand non-DS. Five children in each group were caries-free, while the remainder hadelevated caries experience.S. mutansisolates were obtained from each participant.The genotypic profile of the isolates was analyzed with the AP-PCR methodology.The acidogenicity of a representative strain from each genotype ofS. mutanswas alsoevaluated. DS children had 16 differentS. mutansgenotypes, while the control grouphad 21. Twelve genotypes were present in both groups and one of them was associatedwith caries-free status (P<.05). Although the acidogenicity of the genotypes foundin DS children was significantly lower (P<.05) compared to controls, this fact wasnot associated with caries experience in both groups.Conclusions:DS children have a lowerS. mutansgenotypic diversity and genotypeswith lower acidogenicity than those of non-DS children. However these findings werenot associated with their caries experience