EFFECT OF LACTIC ACID BACTERIA ON BIOFILM FORMATION BY STREPTOCOCCUS MUTANS: AN IN VITRO STUDY

Dental biofilms are majorly developed by Streptococcus mutans, a cariogenic microorganism and are one of the major effects of glucosyltransferases (Gtf) produced by it. This study was conducted to determine the antagonistic potential of probiotic bacteria against S. mutans biofilm formation. We studied the anti-biofilm formation ability of three Lactobacillus species viz L. rhamnosus, L. acidophilus and L. plantarum. Inhibition of biofilm formation was checked on a cell culture cluster. The samples with robust inhibitory activity were selected to check their effect on Gtf activity by estimating the changes in the amount of glucan synthesized, the Gtf catalyzed reaction product. The results showed that, the cell free broth of L. plantarum and L. acidophilus has significant inhibitory and displacement activity on biofilm formation by the cariogenic organism when employed individually and in combination. Further, the interference (80% reduction) in glucan synthesis observed by applying these lactic acid bacteria (LAB) samples suggested their possible role in inhibition of glucosyltransferase (insoluble) [Gtf-I]. In conclusion, our studies demonstrated repressive activities of two LAB species, on the expression of S. mutans virulence genes to reduce its biofilm formation which may be associated with Gtf-I enzyme. Thus the observations would help to develop a potent strategy to combat dental plaque.