Genotypic Diversity Of Streptococcus Mutans And Streptococcus Sobrinus In Uygur Children With Severe Early Childhood Caries Or Without Caries

Aim:To evaluate the genetic diversity of S. mutans and S. sobrinus in isolated Uygur children with severe early childhood caries (SECC) and in caries-free (CF) from rural Kashgar area and explore the assosiation between ECC and cariogenic MS genotype. Methods:Plaque samples were obtained from32SECC and32CF children range26-71months old and cultured to MSB agar.Sm and Ss stains were isolated on the basis of their morphological properties.DNA was prepared and identified with polymerase chain reaction (PCR) again. Arbitrarily primed PCR (AP-PCR) fingerprinting was applied in determining the genotypes of Sm and Ss. Result:The frequency of Sm,Ss in two group is not statistically significant(p>0.05).1-6genotypes of Sm and1-3genotypes of Ss were colonized in different oral cavity of SECC and CF children;75%SECC children and59.4%CF children harboured more than one genotype of Sm,15.7%SECC children and12.5%CF children harboured more than one genotype of Ss. Spearman correlation test showed a strong association between genotypic diversity of Sm and dmft(r=0.439,P<0.05). Conclusion:The number of genotypes per individual was positively associated with the proportion of dmft, The observed diversity of Sm and Ss genotypes represent a pattern of ECC, which suggests that higher dmft are significantly associated with higher diversity of MS genotypes.