Genotyping of Streptococcus mutans by using arbitrarily primed polymerase chain reaction in children with Down Syndrome.

OBJECTIVE

The aim of this study was to compare the caries prevalence between Down Syndrome (DS) and non-DS children and to investigate the difference between the genotypes of Streptococcus mutans (S. mutans) colonized in both DS and non-DS groups.

METHODS

Sixty children with DS and 64 non-DS children aged between 7 and 12 years old were included to this study. All erupted teeth were evaluated according to the criteria recommended by the World Health Organization. Unstimulated saliva samples were carried out from the children and cultivated on S. mutans selective Tryptone-yeast-cystine (TYC) agar with 0.2 U/ml bacitracin and 15% sucrose. Molecular typing of S. mutans strains was performed by using arbitrarily primed polymerase chain reaction (AP-PCR) with OPA-05 primer. All data were analysed by using SPSS (SPSS Inc., Chicago, IL, USA) 11.0 software program for windows.

RESULTS

The caries index scores were found significantly lower in DS individuals than the non-DS group (p < 0.05). The salivary S. mutans levels between DS and non-DS groups did not show significant difference (p > 0.05). The difference between dental caries and salivary S. mutans levels also was not statistically significant (p > 0.05). According to the results of the AP-PCR typing, all profiles of S. mutans which colonized in DS group were different from the control group. The relationship between these different profiles and dental caries prevalence was statistically significant (p < 0.05).

CONCLUSIONS

The profiles of S. mutans colonized in DS group might be a reason of low caries prevalence.