I Neutral plasma activated solution reverse Polymyxin to inhibit polymyxin-resistant Acinetobacter Baumannii by promoting the release of ROS and destroy the outer membrane in vitro

Acinetobacter baumannii is a prominent pathogen linked to ventilator-associated pneumonia (VAP) and has demonstrated widespread multidrug resistance globally. While the exploration of synergistic antibiotic combinations is increasingly viewed as an innovative treatment strategy, the antibacterial potential of Plasma Activated Water (PAW) in neutralizing formulations remains underdeveloped. This study investigates the synergistic interactions between Neutral Plasma Activated Water (NPAW) and Polymyxin B against multidrug-resistant strains of A. baumannii.We evaluated the antibacterial activity of the combination of NPAW and Polymyxin B against polymyxin-resistant A. baumannii strains both in vitro and in vivo, further exploring the underlying mechanisms of synergy. Through checkerboard assay and time-kill studies, we demonstrated that the combination of NPAW and Polymyxin B exhibited a synergistic effect against polymyxin-resistant A. baumannii. In the mouse pneumonia model, we confirmed that the combined treatment significantly reduced bacterial colonization in the lungs. Mechanistic studies indicated that NPAW enhances the bactericidal activity of Polymyxin B by promoting the release of reactive oxygen species (ROS). When used together, NPAW and Polymyxin B decreased the production of intracellular ATP and membrane potential and compromised outer membrane integrity.In conclusion, the synergistic interactions between these agents may enable the use of lower concentrations of Polymyxin B in treating A. baumannii infections, thereby minimizing dose-dependent side effects and providing a novel therapeutic option for managing these infections.