Factors That ImpactPseudomonas aeruginosaBiofilm Structure and Function

Abstract

This chapter focuses on the relationships among biofilm development, the environment, and antimicrobial tolerance for the paradigm organism Pseudomonas aeruginosa. While a specific strain of P. aeruginosa consistently produces the same biofilm structure under one laboratory culturing condition, the same strain produces a very different biofilm structure under different culturing conditions. Investigators have discovered that biofilms grown in vitro reproducibly form specific structures that are affected by a plethora of conditions. For P. aeruginosa, two general biofilm shapes have been observed using the flow cell system: structured biofilms and flat biofilms. While the environmental sensing mechanisms and the regulatory pathways leading to the formation of specific biofilm structures have not been fully elucidated, it is clear that many factors are important for this process. A focus of recent work has been on identifying the signal transduction and regulatory pathways that control biofilm formation and that integrate different environmental signals during biofilm development. The chapter provides an outline about the regulation of biofilm formation by cyclic-di-GMP (c-di-GMP) and two-component systems (TCSs). Researchers are currently trying to determine the nature of these environmental signals, and as they do, our understanding of which environments promote or impair biofilm formation will grow. Microbial fuel cells and wastewater treatment communities are a few examples of engineered, structured communities that could benefit from such an approach.