Pseudomonas aeruginosa Quorum Sensing System (QS) (QS)

The Quorum Sensing (QS) system in Pseudomonas aeruginosa is a sophisticated cell-to-cell communication network that regulates the expression of virulence factors and the formation of biofilms in a density-dependent manner (1, 2). It consists of four interconnected pathways—Las, Rhl, Pqs, and Iqs—which utilize signaling molecules called autoinducers to synchronize group behavior (3, 7). In the context of biofilms, the QS milieu refers to the accumulation of these signals and the resulting coordinated gene expression that leads to antibiotic tolerance and persistent infection (4, 10). Targeting this system with Quorum Sensing Inhibitors (QSIs) or Quorum Quenching (QQ) enzymes aims to attenuate bacterial pathogenicity without exerting the strong selective pressure for resistance seen with traditional bactericidal antibiotics (12, 16). This approach is particularly relevant for treating chronic infections in cystic fibrosis and immunocompromised patients where P. aeruginosa biofilms are highly recalcitrant to standard therapy (8, 14). By disrupting the communication that maintains the biofilm structure and virulence, these agents can potentially restore the efficacy of conventional antibiotics and aid host immune clearance (10, 12).

Other names

Pseudomonas aeruginosa quorum sensing systemLas systemRhl systemPqs systemIqs systemCell-to-cell communication systemAutoinduction system

Quorum sensing inhibition (QSI) via signal synthesis inhibition, signal receptor antagonism, and enzymatic signal degradation (quorum quenching).