Quorum-Sensing C12-HSL Drives Antibiotic Resistance Plasmid Transfer via Membrane Remodeling, Oxidative Stress, and RpoS-RMF Crosstalk.

Antibiotic misuse accelerates resistance dissemination via plasmid conjugation, but quorum sensing (QS) regulatory mechanisms remain undefined. Using () MG1655 conjugation models (RP4-7/EC600 plasmids), we demonstrate that long-chain acyl-homoserine lactones (C10/C12-HSL) enhance transfer frequency by up to 7.7-fold (200 μM C12-HSL; < 0.001), while quorum-quenching by sub-inhibitory vanillin suppressed this effect by 95% ( < 0.0001). C12-HSL compromised membrane integrity via upregulation (4-fold; < 0.01) and conjugative pore assembly ( upregulated by 1.38-fold; < 0.05), coinciding with ROS accumulation (1.5-fold; < 0.0001) and SOS response activation ( upregulated by 1.68-fold; < 0.001). Crucially, and deletion mutants reduced conjugation by 65.5% and 55.8%, respectively ( < 0.001), exhibiting attenuated membrane permeability (≤65.5% reduced NPN influx; < 0.0001), suppressed ROS (≤54% downregulated; < 0.0001), and abolished transcriptional induction of conjugation/stress genes. Reciprocal RpoS-RMF (ribosomal hibernation factor) crosstalk was essential for AHL responsiveness, with deletions mutually suppressing expression (≤65.9% downregulated; < 0.05). We establish a hierarchical mechanism wherein long-chain AHLs drive resistance dissemination through integrated membrane restructuring, stress adaptation, and RpoS-RMF-mediated genetic plasticity, positioning QS signaling as a viable target for curbing resistance spread.