Quorum-sensing system of Pseudomonas aeruginosa (QS system)

The Quorum-sensing (QS) system of Pseudomonas aeruginosa is a complex, hierarchical regulatory network that allows the bacterium to coordinate gene expression based on population density. It primarily consists of four interconnected pathways—Las, Rhl, Pqs, and Iqs—which utilize signaling molecules called autoinducers to regulate the production of virulence factors and the formation of biofilms (Papenfort & Bassler, 2016). In clinical settings, this system is a critical driver of chronic infections, particularly in patients with cystic fibrosis or compromised immune systems, as it enables the pathogen to evade host defenses and resist conventional antibiotics (Lee & Zhang, 2015). Therapeutic strategies targeting the QS system, known as quorum quenching, aim to attenuate bacterial virulence without necessarily killing the bacteria, thereby reducing the selective pressure for resistance (Moradali et al., 2017). Experimental drugs and natural compounds often act by inhibiting the synthesis of autoinducers or by competitively binding to receptor proteins like LasR and PqsR to prevent the activation of downstream pathogenic pathways (Schoenfelder et al., 2018). This approach represents a promising "anti-virulence" strategy to manage multi-drug resistant Pseudomonas infections.

Other names

Las/Rhl/Pqs/Iqs systemPseudomonas cell-to-cell communication networkLasR-LasI systemRhlR-RhlI systemPqsR-PqsABCD systemMvfR-regulated pathway

Quorum quenching via competitive antagonism of receptors (LasR, RhlR, PqsR), inhibition of autoinducer synthases, or enzymatic degradation of signaling molecules.