Biofilm dispersion and quorum sensing

Biofilm development and quorum sensing (QS) are closely interconnected processes. Biofilm formation is a cooperative group behaviour that involves bacterial populations living embedded in a self-produced extracellular matrix. QS is a cell-cell communication mechanism that synchronizes gene expression in response to population cell density. Intuitively, it would appear that QS might coordinate the switch to a biofilm lifestyle when the population density reaches a threshold level. However, compelling evidence obtained in different bacterial species coincides in that activation of QS occurs in the formed biofilm and activates the maturation and disassembly of the biofilm in a coordinate manner. The aim of this review is to illustrate, using four bacterial pathogens as examples, the emergent concept that QS activates the biofilm dispersion process.