Abstract

Synergetic activity of a quorum sensing inhibitor and antibiotics to combat oral adhesivity of Streptococcus mutans

Author(s): S.Adline Princy, D.Bharath, V.Praveen Krishna, Gurmeet Kaur

Streptococcus mutans is the principal pathogen causing human dental caries which can switch between planktonic and biofilm (plaque) forms on oral surfaces. This eventually leads to the development of dental caries and a marked reduction in the effectiveness of antibiotic treatment. The objective of the study is to evaluate the effect of the compounds characterized from the bark ethanolic extract of Melia dubia (quorum sensing inhibitor) that could curtail the biofilmformation and subsequent adhesion of S. mutans and synergistically bolster the activity of antibiotics by regulation of gene expression. The results reveal that at a concentration of 20ìg/ml, the extract has a consistent biofilminhibitory action that also corresponds to a near-normal cell growth, suggesting the absence of antibiotic activity. This concentration of extract shows a considerable increase in biofilm inhibition and reduction in cell growth when used in combination with penicillin (MIC of 30mg/mL) and gentamycin (MIC of 10mg/ml). This Quorum Sensing Inhibitor (QSI) in the bark extract has a great potential in eliminating the biofilm of S. mutans, especially when used in a combinatorial control regime with penicillin and hence is a promising solution to eradicate the complications arising out of dental plaque formation.