Molecular characterization of Streptococcus mutans gtfB gene isolated from families

OBJECTIVE: Caries is a multifactorial infectious disease and the main etiological agent is the bacteria Streptococcus mutans due to its virulence factors, which enable the adherence to dental enamel and favours the formation of dental biofilm through the production of extracellular polysaccharides. The transmission of S. mutans can occur between people, often within families. The present study aimed to evaluate the intrafamily genetic pattern of S. mutans through partial sequencing of the gene that encodes the glucosyltransferase β (gtfB) enzyme.METHODS: We previously analyzed saliva samples from 40 individuals from nine families, and it was obtained 64 isolates biochemically characterized as S. mutans. The isolates were evaluated by random amplification of polymorphic DNA (RAPD). Those with greater similarity were characterized by partial sequence 16S rRNA gene and the gtfB gene sequencing.RESULTS: It was observed genetic similarity among strains isolated from individuals with caries activity; while isolates from individual without caries showed that they are genetically distinct, suggesting a different virulence pattern.CONCLUSION: The present results demonstrated that partial sequencing of the gtfB gene showed to be a potential marker to investigate genetic pattern and virulence of S. mutans, deserving further investigation in order to identify families at risk of caries.