Conventional oxidative disinfection methods are usually inefficient to eliminate intracellular antibiotic resistance genes (i-ARGs) due to competitive oxidation of cellular components of antibiotic-resistant bacteria (ARB), resulting in the ubiquitous occurrence of ARGs in drinking water systems. Herein, we developed the strategy of coupling electroporation and electrochemical oxidation on a Co3O4-nanowires-modified electrode to destroy the multiresistant Escherichia coli cells and promote subsequent i-ARG (blaTEM-1 and aac(3)-II) degradation. The lightning-rod effect over nanowire tips can form finite regions with a locally enhanced electric field and highly concentrated charge density, in turn facilitating the electroporation for ARB cell damage and electrochemical reactivity for reactive chlorine/oxygen species generation. Characterization of the ARB membrane integrity and morphology revealed that electroporation-induced cell pores were further enlarged by the oxidation of reactive species, resulting in i-ARG removal at lower applied voltages and with 6-9 times lower energy consumption than the conventional electrochemical oxidation approach with a Co3O4-film-modified electrode. The satisfactory application and effective inhibition of horizontal gene transfer in tap water further demonstrated the great potential of our strategy in the control of the ARG dissemination risk in drinking water systems.
Keywords: cell damage; electrochemical oxidation; electroporation; intracellular antibiotic resistance genes; reactive species.