Production of glucosyltransferase B and glucans by Streptococcus mutans strains isolated from caries-free individuals.

Glucosyltransferase B is an enzyme produced by Streptococcus mutans, which catalyzes synthesis from sucrose of insoluble glucans that provide support to the biofilm. It is one of the main virulence factors in the generation of dental caries. However, its role is unclear in caries-free individuals who carry the bacteria. The aim of this study was to determine the production of glucosyltransferase B and the production of glucans by Streptococcus mutans strains isolated from biofilms of 30 caries-free individuals. Strains were grown in Todd Hewitt broth. Extracellular proteins were obtained by ammonium sulfate precipitation and associated membrane proteins by extraction with urea. The presence of GtfB was determined by molecular weight by SDS-PAGE and confirmed by Western blotting using a specific monoclonal antibody and polysaccharide production by electrophoretic separation, incubation with sucrose and Schiff staining. The results show that 96.7% of strains of Streptococcus mutans produce a band at the position of the molecular weight corresponding to the glucosyltransferases, of which 63.4% are positive by Western blot. Polysaccharides are produced by 93.3% of the strains.

CONCLUSIONS

Streptococcus mutans strains isolated from biofilm of healthy individuals produce virulence factors associated with dental caries, such as glucans and glucosyltransferase B. This indicates that there are conditions in the oral cavity different from these factors that keep the individual free from dental caries, which should be investigated in the search for strategies to control the disease.