Biofilms by bacterial human pathogens: Clinical relevance - development, composition and regulation - therapeutical strategies

Abstract

Notably, bacterial biofilm formation is increasingly recognized as a passive virulence factor facilitating many infectious disease processes. In this review we will focus on bacterial biofilms formed by human pathogens and highlight their relevance for diverse diseases. Along biofilm composition and regulation emphasis is laid on the intensively studied biofilms of Vibrio cholerae, Pseudomonas aeruginosa and Staphylococcus spp., which are commonly used as biofilm model organisms and therefore contribute to our general understanding of bacterial biofilm (patho-)physiology. Finally, therapeutical intervention strategies targeting biofilms will be discussed.

Keywords: Pseudomonas aeruginosa; Vibrio cholerae; biofilm; biofilm-associated disease; nosocomial infections; staphylococci; treatment.

Figure 1. FIGURE 1: Biofilm formation is a common feature among bacterial human pathogens.

Bacterial biofilms by human pathogens are found on various tissues of the human body, on medical devices, e.g. catheters or prostheses, and in the environment, representing a reservoir for new infections. A schematic overview indicating representative bacterial species associated with biofilm-related diseases and their occurrence in the body (arrows) is presented on the left. Biofilm formation (upper right) is a multistep process organized in an attachment, maturation and detachment phase. Biofilm formation is controlled and modulated by several factors including bacterial surface molecules, secreted matrix effectors, as well as environmental components and stressors. Thus, it is not surprising that bacterial biofilm regulation (lower right) involves the interplay of several positive and negative regulatory cascades including quorum sensing systems (QS), regulatory small RNAs (sRNAs), alternative sigma factors, two-component systems and second messengers, such as c-di-GMP.