Quorum sensing is a process of cell-cell communication that allows bacteria to 
share information about cell density and adjust gene expression accordingly. 
This process enables bacteria to express energetically expensive processes as a 
collective only when the impact of those processes on the environment or on a 
host will be maximized. Among the many traits controlled by quorum sensing is 
the expression of virulence factors by pathogenic bacteria. Here we review the 
quorum-sensing circuits of Staphylococcus aureus, Bacillus cereus, Pseudomonas 
aeruginosa, and Vibrio cholerae. We outline these canonical quorum-sensing 
mechanisms and how each uniquely controls virulence factor production. 
Additionally, we examine recent efforts to inhibit quorum sensing in these 
pathogens with the goal of designing novel antimicrobial therapeutics.