Quorum Sensing: The Complexities of Chemical Communication between Bacteria

It is becoming increasingly clear that bacteria are able to communicate with each other to regulate gene expression in a concerted way, dependent upon the population density, by a process termed ‘quorum sensing’ (QS). Here we review N-acyl homoserine lactone-mediated QS in Gram-negative bacteria, and, in particular, its importance in vivo, in pathogenicity and virulence. We also describe systems that have been developed by other organisms to either exploit or interfere with bacterial QS.