Bacterial quorum sensing and motility pathways (QS/Motility)

Bacterial quorum sensing (QS) and motility pathways are complex regulatory networks that enable bacteria to coordinate collective behaviors, such as virulence factor production and biofilm formation, in response to population density [1.1.3, 1.2.1]. These systems rely on the synthesis and detection of signaling molecules called autoinducers, including N-acyl homoserine lactones (AHLs) in Gram-negative bacteria and autoinducing peptides (AIPs) in Gram-positive species [1.1.1, 1.2.1]. Motility pathways, including swarming and twitching, are often co-regulated by QS to facilitate colonization and spread within a host [1.3.2, 1.4.2]. Targeting these pathways is a key 'anti-virulence' strategy aimed at disarming pathogens without directly killing them, thereby reducing the selective pressure for antibiotic resistance [1.3.1, 1.4.2]. Various drugs, including sub-inhibitory concentrations of macrolides like azithromycin and repurposed agents such as piroxicam, have been shown to disrupt these pathways by inhibiting signal synthesis, reception, or downstream gene expression [1.3.4, 1.3.5]. The molecular components of these pathways include autoinducer synthases (e.g., LuxI homologs), receptors (e.g., LuxR homologs like LasR and RhlR), and enzymes involved in signal metabolism like 5'-methylthioadenosine nucleosidase (MTAN) [1.1.3, 1.2.2]. Inhibition can be achieved through small molecules that compete with autoinducers for receptor binding or by 'quorum quenching' enzymes that degrade the signals [1.1.4, 1.3.3]. While these pathways are not essential for basic bacterial growth, they are critical for pathogenesis, making them attractive targets for treating chronic and multi-drug resistant infections [1.2.3, 1.3.2]. However, challenges remain regarding the potential for off-target effects on host signaling and the need for effective delivery into dense biofilm structures [1.2.1, 1.4.2].

Other names

Quorum sensing systemBacterial cell-to-cell communicationQuorum sensing circuitsAnti-virulence pathwaysBacterial communication pathways

Inhibition of autoinducer synthesis, competitive inhibition of signal receptors, enzymatic degradation of signaling molecules (quorum quenching), and interference with downstream gene transcription.