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.
['Koo|H|H|', 'Falsetta|M L|ML|', 'Klein|M I|MI|']
D018441:Biofilms D060833:Cellular Microenvironment D003731:Dental Caries D003773:Dental Plaque D006801:Humans D006863:Hydrogen-Ion Concentration D011135:Polysaccharides, Bacterial D013295:Streptococcus mutans D014774:Virulence
dental caries extracellular matrix heterogeneity Streptococcus mutans glucosyltransferases pH microenvironment