Estimating Genotypic Diversity of Streptococcus mutans Isolated From Caries-Active and Caries-Free Individuals Among Indian Population.

Purpose To identify the genetic characterization of S mutans strains isolated from the caries-free and caries-active population using arbitrarily primed -polymerase chain reaction (AP-PCR). Materials and methods Thirty-five subjects with a decayed missing and filled teeth (DMFT) score of 0 were allocated to the caries-free group and 35 subjects with a DMFT score greater than four were allocated to the caries-active group and salivary samples were collected. The samples were processed and the colony forming units (CFU) of S mutans were determined for all the samples. About three colonies resembling S mutans from each subject were subjected to deoxyribonucleic acid (DNA) isolation, a purification process was performed, and DNA was analyzed by AP-PCR. Results Among the 210 isolates from 35 caries-active and 35 caries-free subjects that were analyzed by AP-PCR, 41.9% had a single genotype, 25.8% had two genotypes, 19.4% had three genotypes, 9.7% had four genotypes and 3.2% had more than four genotypes among the caries-free group. Among the caries-active group, 54.3% had a single genotype, 25.7% had two genotypes, 14.3% had three genotypes and 5.7% had four genotypes. Conclusion The study concluded that different genotypic pattern was present in caries-free and caries-active subjects which indicate the occurrence of genetic polymorphism among the S mutans strains. There was no particular genotype of S mutans that was uniquely present in subjects in caries-active and caries-free individuals.