The Exopolysaccharide Matrix: A Virulence Determinant of Cariogenic Biofilm

Many infectious diseases in humans are caused or exacerbated by biofilms. dental caries is a prime example of a biofilm-dependent disease,resulting from interactions of microorganisms,host factors,and diet (sugars),which modulate the dynamic formation of biofilms on tooth surfaces. all biofilms have a microbial-derived extracellular matrix as an essential constituent. the exopolysaccharides formed through interactions between sucrose- (and starch-) and streptococcus mutans-derived exoenzymes present in the pellicle and on microbial surfaces (including non-mutans) provide binding sites for cariogenic and other organisms. the polymers formed in situ enmesh the microorganisms while forming a matrix facilitating the assembly of three-dimensional (3d) multicellular structures that encompass a series of microenvironments and are firmly attached to teeth. the metabolic activity of microbes embedded in this exopolysaccharide-rich and diffusion-limiting matrix leads to acidification of the milieu and,eventually,acid-dissolution of enamel. here,we discuss recent advances concerning spatio-temporal development of the exopolysaccharide matrix and its essential role in the pathogenesis of dental caries. we focus on how the matrix serves as a 3d scaffold for biofilm assembly while creating spatial heterogeneities and low-ph microenvironments/niches. further understanding on how the matrix modulates microbial activity and virulence expression could lead to new approaches to control cariogenic biofilms. © 2013,international & american associations for dental research. all rights reserved.