Microbial biofilms in ophthalmology and infectious disease.

Most bacterial infections involve biofilms. Biofilms are collections of microorganisms encased in a matrix that is often composed of both bacterial and host materials. They form on natural surfaces such as heart valves or abiotic surfaces such as contact lenses or intraocular lenses. The biofilm matrix promotes adherence of the microbe to smooth surfaces as well as to other cells. Biofilms thereby form large 3-dimensional microbial communities of complex architecture through cell-to-cell communication and coordinated multicellular behavior. The biofilm architecture promotes the exchange of nutrients and waste products. The ability of microorganisms to attach to abiotic surfaces and grow in highly stable communities greatly confounds the medical use of implantable devices. Much effort is now being invested to understand the molecular nature of biofilms, with a view toward designing biofilm-resistant implantable devices and more effective antimicrobials.