Biofilms, infectious agents, and dental unit waterlines: a review

Aquatic biofilms, which are widespread not only in nature but also in medic al and dental devices, can be the source of serious nosocomial infections. In these hardy microbial communities, pathogens like nontuberculous mycobac teria, Pseudomonas aeruginosa, Legionella pneumophila, and other bacteria n ot only survive but proliferate and lie in wait for susceptible hosts. Not only are these organisms intrinsically resistant to high temperatures and b iocides, but the biofilms they inhabit enhance their resistance. This shoul d be of concern to infection control practitioners. The bacterial colonizat ion of dental unit waterlines can be used as a model to investigate the pro blem of waterborne biofilms in health care settings.