Biofilms – the problem

A biofilm is a complex aggregation of micro-organisms living in a protective and adhesive matrix.

Biofilms are triggered by many factors - these include a chemical signaling mechanism between bacteria, called quorum sensing. This is the ability of bacteria to communicate and coordinate behavior via chemical signaling molecules which activate intracellular receptors to effect the up regulation of specific genes, such as virulence genes responsible for the production of proteases and toxins, and those responsible for the formation of biofilms.

The biofilm environment makes bacterial infections much harder to treat or remove - biofilms protect bacteria from the effects of the immune system, or of detergents and antibiotics, as the dense extracellular matrix and the outer layer of cells actively prevent access to the interior of the community. For example, up to 1000-fold higher doses of antibiotics may be required to eradicate biofilm-contained bacteria relative to their free counterparts and this may also contribute to the development of antibiotic resistant strains of bacteria.

Biofilms are ubiquitous - they are widespread in the environment, but also in industry, they can develop on the interiors of pipes, leading to clogging and corrosion, and their growth on floors and counters can make sanitation difficult in food preparation areas. In humans, biofilms contribute to a wide variety of microbial infections in the body, and are potentially involved in up to 80% of all infections. These include urinary tract infections, catheter infections, middle-ear infections, formation of dental plaque, gingivitis, and contact lens associated eye infections. Furthermore, biofilms contribute in a major way to the morbidity and mortality associated with endocarditis, infections in cystic fibrosis, and infections of permanent indwelling devices such as joint prostheses and heart valves.

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