The correlation between the sortaseA genotype of Streptococcus mutans and high-severity childhood caries

Objectives To make a primary research on the relationship between genotypes of sortase A gene (srtA) of Streptococcus mutans (S.mutans) and high-severity childhood caries on the base of existenceof no other factors related to childhood caries. Methods The ABI Variant Reporter software was used to analyze the genotypes of the srtA gene of 121 S.mutans strains isolated from the high-severity caries children and 121 S.mutans strains isolated from the caries-free children. Bivariate analysis was used to analyze the srtA genotype distribution and the frequencies of social and behavioural variants between groups. Multiple logistic regression models were used to assess the relationship between the srtA genotype and childhood caries after controlling confounding factors. Results A total of 15 genotypes were found: 9 in caries free group and 11 in high-severity caries group. The frequency of 3A genotype was significantly higher in caries free group than high-severity caries group (P= 0.033) . The frequency of 3E genotype was significantly higher in high-severity caries group than caries free group (P= 0.037) . The best-fitting model showed that older age (months) , low weight at birth, high frequencies of solid sugar consumption, prolonged breastfeeding, a high proportion of visible plaque, and 3A genotype of the srtA gene of S.mutans were associated with high-severity caries in children. Conclusions The present study suggested that the 3A genotype of the srtA gene of S.mutans may correlate with caries susceptibility in children. In addition, age, weight at birth, duration of breastfeeding, solid sugar consumption, and poor oral hygiene contributed to primary childhood caries. Key words: Caries; Streptococcus mutans; SrtA; Genotype