The role of bacterial biofilms in ocular infections

There is increasing evidence that bacterial biofilms play a role in a variety of ocular infections. Bacterial growth is characterized as a biofilm when bacteria attach to a surface and/or to each other. This is distinguished from a planktonic or free-living mode of bacterial growth where these interactions are not present. Biofilm formation is a genetically controlled process in the life cycle of bacteria resulting in numerous changes in the cellular physiology of the organism, often including increased antibiotic resistance compared to growth under planktonic conditions. The presence of bacterial biofilms has been demonstrated on many medical devices including intravenous catheters, as well as materials relevant to the eye such as contact lenses, scleral buckles, suture material, and intraocular lenses. Many ocular infections often occur when such prosthetic devices come in contact with or are implanted in the eye. For instance, 56% of corneal ulcers in the United States are associated with contact lens wear. Bacterial biofilms may participate in ocular infections by allowing bacteria to persist on abiotic surfaces that come in contact with, or are implanted in the eye, and by direct biofilm formation on the biotic surfaces of the eye. An understanding of the role of bacterial biofilm formation in ocular infections may aid in the development of future antimicrobial strategies in ophthalmology. We review the current literature and concepts relating to biofilm formation and infections of the eye.