Quorum sensing pathways in Pseudomonas aeruginosa and Staphylococcus aureus (QS pathways (P. aeruginosa/S. aureus))

Quorum sensing (QS) pathways are sophisticated chemical communication systems used by bacteria to coordinate collective behaviors based on population density. In Pseudomonas aeruginosa, a Gram-negative pathogen, the system primarily relies on acyl-homoserine lactones (AHLs) and quinolone signals (PQS) acting through LuxR-type transcription factors like LasR and RhlR to regulate virulence factors and biofilm architecture. In Staphylococcus aureus, a Gram-positive pathogen, the Accessory Gene Regulator (Agr) system utilizes autoinducing peptides (AIPs) and a two-component signaling system (AgrC/AgrA) to switch between colonizing and invasive phenotypes. These pathways are critical therapeutic targets because their inhibition, known as quorum quenching, can attenuate bacterial pathogenicity and increase susceptibility to antibiotics without directly killing the bacteria, potentially reducing the selective pressure for resistance. Targeting these systems is particularly relevant for treating chronic infections such as those found in cystic fibrosis lungs or non-healing wounds where biofilms are prevalent.

Other names

Bacterial cell-to-cell communicationLasI/LasR systemRhlI/RhlR systemPQS systemAgr systemAccessory gene regulator systemQuorum quenching targets

Inhibition of autoinducer synthesis, competitive antagonism of quorum sensing receptors, enzymatic degradation of signaling molecules (quorum quenching), and inhibition of downstream response regulators.