Biofilms, Quorum Sensing and Crosstalk in Medically Important Microbes

Biofilms are heterogeneous communities of microorganisms firmly attached to a biological or abiotic surface. They are the causative agents of chronic infection in over 25 different diseases and the microbes that comprise biofilms are typically highly tolerant to antimicrobials. Biofilm formation is a highly coordinated process that relies heavily on a cell-density-dependent form of microbial communication called ‘quorum sensing’ (QS). QS is facilitated by the production of small-molecule signals that induce shifts in gene expression and metabolic activity in the organisms residing in and around biofilms. Quorum signals can elicit specific responses in a wide range of both prokaryotic and eukaryotic cells, and this ‘crosstalk’ or ‘interkingdom signalling, (IKS) travels both directions, as some mammalian hormones can directly enhance bacterial virulence. Since QS controls the pathogenic processes of so many medically important microbes, it holds significant promise as a future target for therapeutics.