[Extracellular matrix as a microbial virulence factor in the development of human diseases].

Extracellular polymers which build a biofilm matrix possess a complicated structure, where the polysaccharide fraction, composed of homo- or heteropolysaccharides, is the largest. Other important components are proteins, eDNA, glycoproteins and lipids. The matrix has a protective function against the surrounding environment, plays a role in biofilm formation and maturation processes, stabilizes the biofilm structure, and also is a source of nutrients and water for the cells. It is noteworthy that the biofilm matrix is a virulence factor and plays an important role in the pathogenesis of many human diseases. Pseudomonas aeruginosa growing in the lungs of patients with cystic fibrosis produces three major exopolysaccharides (Pel, Psl and alginate) and synthesizes numerous proteins such as lectins and enzymes, e.g. PasP, chitinase, aminopeptidase, and protease IV, which facilitate the tissue colonization. Extracellular polymers play a significant role in the course of caries, which is associated with the development of multi-species biofilm on the teeth surface. The structure of the matrix surrounding that biofilm is complicated--different for each patient. The components of the matrix are constantly changing depending on the environmental conditions, e.g. the presence of sucrose affects the synthesis of mutan and dextran. Infections associated with biofilm formation on implants pose significant medical and economic problems. The main components of the matrices are saccharides (e.g., PIA, EC-TA), as well as surface and extracellular proteins. Studies on the matrix structure and the factors regulating its synthesis are necessary to develop techniques for biofilm eradication and better control of biofilm-related infections.