* Quorum sensing is a type of bacterial communication that arises when cell population density is high.
— Quorum sensing is mediated by autoinducers, which are molecules released by bacterial cells.
— As cell density increases, so does autoinducer concentration.
— In different species, quorum sensing moderates
virulence factor secretion, biofilm production, sporulation, and other behaviors.
— For example, consider the bacteria
Staphylococcus aureus, which produces
autoinducer peptides (AIPs).
— When the density of
S. aureus increases, so does the concentration of autoinducer peptides. In turn, this induces bacterial release of virulence factors, including several toxins.
Furthermore, the cells are stimulated to release additional AIPs, thus creating a positive feedback loop.
Because quorum sensing facilitates some of the harmful effects of acute
S. aureus infection, researchers are investigating treatments that prohibit or moderate this type of cellular communication.
