OH and 1O2 mediated oxidative reduction of antibiotic-resistant bacteria cultivability and tetA abundance in a 3D electro-Fenton system.

The proliferation of antibiotic-resistant bacteria (ARB) in aquatic environments necessitates efficient remediation strategies. This study developed a three-dimensional electro-Fenton (3DEF) system employing a novel MnO2/Pd(Ⅱ)@CA particle electrode to simultaneously inactivate tetracycline-resistant Escherichia coli (TR E. coli) and mitigate antibiotic resistance dissemination. Under optimal conditions (1.5 V, 12 mM Fe2+, 1.5 g L-1 particle electrode, pH 5), complete inactivation of TR E. coli (> 7-log reduction) was achieved within 4 min. The particle electrode promoted in-situ H2O2 generation, subsequently activated to produce •OH and 1O2 as dominant reactive species, with reactive chlorine species also contributing. Scanning electron microscopy confirmed extensive membrane disruption, accompanied by substantial leakage of intracellular K+ and proteins. Both intracellular and extracellular tetracycline resistance genes (tetA) were detected, while residual extracellular DNA lost transformation capability, indicating reduced dissemination potential. Proteomic analysis revealed suppression of the AcrAB-TolC efflux pump, disrupted DNA repair pathways, and impaired energy metabolism, ultimately leading to complete loss of viability and regrowth capacity. This work highlights the 3DEF system as a promising technology for mitigating environmental risks posed by ARB.