ABSTRACT
In nature, almost all microorganisms grow as part of communities attached to surfaces that are bathed by liquid, generally water. These organised surface-adherent communities are termed biofilms and are the way that bacteria and fungi grow on external and internal surfaces of the human body, or on catheters and prostheses. In nature, and in the human body, biofilms are generally multi-species consortia; however, single-species biofilms can occur on catheters and indwelling prostheses in the human body. The bacteria that colonise the skin are largely gram-positive and their cell envelopes contain extensively cross-linked peptidoglycans to resist desiccation; thus, one might ask whether the skin has a biofilm. The majority of the biofilm is composed of heterogeneous hydrated extracellular polysaccharide that is responsible for the mechanical and physiological properties of the biofilm. The range of interactions between biofilm bacteria can run the gamut between cooperation and competition.
