Anti-Biofilm Activity of a Self-Aggregating Peptide against Streptococcus mutans

Abstract

<i>Streptococcus mutans</i> is the primary agent of dental cavities, in large part due to its ability to adhere to teeth and create a molecular scaffold of glucan polysaccharides on the tooth surface. Disrupting the architecture of <i>S. mutans</i> biofilms could help undermine the establishment of biofilm communities that cause cavities and tooth decay. Here we present a synthetic peptide P1, derived from a tick antifreeze protein, which significantly reduces <i>S. mutans</i> biofilm formation. Incubating cells with this peptide decreased biofilm biomass by approximately 75% in both a crystal violet microplate assay and an <i>in vitro</i> tooth model using saliva-coated hydroxyapatite discs. Bacteria treated with peptide P1 formed irregular biofilms with disconnected aggregates of cells and exopolymeric matrix that readily detached from surfaces. Peptide P1 can bind directly to <i>S. mutans</i> cells but does not possess bactericidal activity. Anti-biofilm activity was correlated with peptide aggregation and β-sheet formation in solution, and alternative synthetic peptides of different lengths or charge distribution did not inhibit biofilms. This anti-biofilm peptide interferes with <i>S. mutans</i> biofilm formation and architecture, and may have future applications in preventing bacterial buildup on teeth.