Composition and Functional Role of Polysaccharides and Extracellular Polymeric Substances in Gram-positive Biofilm Infections
Christian Theilacker and Johannes Hübner
from: Bacterial Polysaccharides: Current Innovations and Future Trends (Edited by: Matthias Ullrich). Caister Academic Press, U.K. (2009)
Biofilms seem to be the default mode of growth for most if not all bacterial species and this phenomenon has profound consequences in numerous clinical settings. For Gram-positive bacteria several mechanisms involving surface proteins and carbohydrate-containing structures have been identified. Poly-N-acetylglucosamine (PIA/PNAG) has been first described in staphylococci but recently has been shown to be present also in a large number of different bacterial species. Mutants in the gene locus responsible for the synthesis of this molecule lead to a biofilm-negative phenotype. Teichoic acids are polyanionic molecules found in the cell walls of Gram-positive bacteria with low GC content. Teichoic acids are either attached covalently to the peptidoglycan (wall teichoic acids) or inserted into the cell membrane (lipoteichoic acids) and both types have been associated with biofilm formation and adhesion to eukaryotic cells. Recent evidence indicates that extracellular DNA may also be involved in biofilm formation and primary attachment of many Gram-positve organisms and this fact may explain previous observations that autolysin-defective mutants are also impaired in biofilm formation. A more detailed understanding of the molecules involved in biofilm formation is needed to device novel treatment and preventive approaches for Gram-positive infections read more ...