Current and Emergent Control Strategies for Medical Biofilms

In nature, microorganisms prefer to live in structured microbial communities rather than as free-floating planktonic cells. These dynamic microbial communities are termed biofilms, in which transitions between planktonic and sessile modes of growth occur interchangeably in response to different environmental cues. Such phenomenas are advantageous for microbial pathogens but disadvantageous for human health. Due to the increased resistance/tolerance of biofilm cells to antimicrobial treatment, it becomes difficult to eradicate pathogens, which results in relapses of infections even after appropriate therapy. In clinically relevant biofilms, Pseudomonas spp., Staphylococcus spp., and Candida spp. are the most frequently isolated microorganisms. These microorganisms are able to adhere to and colonize surfaces of medical devices such as central venous catheters, intrauterine devices, voice prostheses, and prosthetic joints, resulting in the development of a biofilm. Many antimicrobial agents are now being used against microbial biofilms. However, inappropriate use of conventional antibiotic therapy may also contribute to inefficient biofilm control and to the dissemination of resistance. Consequently, new control strategies are constantly emerging to control biofilm-associated infections, such as the antifungal lock therapy, improved drug delivery, penetration of matrix-attacking extracellular polymetric substances, and regulation of biofilm inhibition/disruption by manipulating small molecules. The present chapter is focused on describing the clinical aspects of biofilm formation and deleterious effects associated with their presence. This chapter will highlight current and emergent control strategies for biofilms.