Influence of agents and extracellular matrix in the generation of persisters cells in biofilms and characterization of the extracellular matrix produced by persisters cells

Abstract

Dental caries is a worldwide public health problem caused by the interaction between microorganisms in the biofilm and the diet. A diet rich in carbohydrates provides substrates for acid production and extracellular matrix build-up. This matrix is rich in exopolysaccharides to which extracellular DNA and lipoteichoic acids are associated. The matrix maintains the acids inside the biofilms and at the interface biofilm-teeth surfaces, hindering the neutralization by saliva and leading to teeth demineralization. Among the preventive approaches for dental caries are the mechanical removal of biofilm, use of fluoride to promote remineralization, and diet control (sugar restriction) but with limited success. Therefore, approaches to prevent dental caries are needed, such as the use of bioactive agents that affect the virulence and/or the ability of pathogenic microorganisms to develop biofilms, especially matrix build-up. However, little is known about how the use of antimicrobial and antibiofilm agents is involved in the tolerance and resistance. Also, it is unknown how the active principles of treatments act on the generation of persisters cells (i.e., cells that exhibit tolerance to several drugs, favoring their survival in the biofilm). The matrix is a trait inherent to all biofilms; however, it is unknown the role of persisters cells in the matrix production and build-up (and vice-versa). Thus, the proposal will investigate how agents and extracellular matrix influence the generation of persisters cells in biofilms and will characterize the matrix derived from persisters cells. Agents will be used to generate persisters cells that will be used for biofilm formation. The characterization of biofilms will be via quantification of microbial population and matrix components, tridimensional structure, and gene expression. The data will be evaluated using statistical tests (±=0.05). (AU)