Microbial biofilms: case reviews of bacterial and fungal pathogens persisting on biomaterials and environmental substrata

In nature, bacteria and fungi inhabit distinct environmental niches at the interface between two phases, such as air and water, or water and a substratum. In these locations, cells are anchored together by means of a multivariate combination of biomolecules which form a barrier surrounding the cells, and acts to protect against adverse conditions, such as temperature, or from chemical attack, such as chlorine in potable water. In clinical settings, human pathogens are able to survive host-mediated phagocytosis or antibiotic attack through the formation of biofilms on host surfaces such as mucous membranes, as well as medical devices such as catheters and cardiovascular stents. In the environment, biofilms are essential for the survival of many species, and have been demonstrated to provide human pathogens with a means of surviving outside of a host organism to present a vehicle for the subsequent reinfection of a susceptible population. For these reasons, biofilm microbiology has risen to prominence when assessing patient care and when investigating outbreaks of disease. This chapter will explore four examples of microbial biofilms as models of infection and persistence. The origin of the microbes within the biofilms will be explored, as will the development of the communities, followed by treatment strategies, the consequences of poor hygiene and antibiotic stewardship, where appropriate.