Simultaneous removal of antibiotic resistant bacteria and antibiotic resistance genes by molybdenum carbide assisted electrochemical disinfection

Considering conventional disinfection methods are not effective in simultaneously removing ARB and ARGs, a novel electrochemical disinfection (ED) process assisted by molybdenum carbide (Mo2C) electrodes was developed in this study. The established ED process was proved to effectively inactivate multi-resistant ARB (i.e. Escherichia coli K-12 LE392 with resistance to kanamycin, ampicillin, and tetracycline) and to degrade ARGs (including tetA and blaTEM in the form of both intracellular (iARGs) and extracellular ARGs (eARGs)). Specifically, within 15 min treatment by the Mo2C-assisted ED under 2.0 V, a 5-log ARB removal was realized, without any ARB regrowth observed, indicating a permanent inactivation of ARB by the process. Moreover, degradation of the iARGs (0.4-log reduction of the blaTEM and 3.1-log reduction of the tetA) and the eARGs (4.2-log reduction of the blaTEM and 1.1-log reduction of the tetA) were achieved within 60 min, further underpinning the viability of the Mo2C-based ED. While e-, H2O2, and •O2- played leading roles in the entire process of ED, H+ and •OH contributed to bacterial inactivation in the early and late stages of ED, respectively. The reactive species induced by electrolysis posed pressure to the ARB strains, which enhanced oxidative stress response, triggered higher reactive oxygen species generation, induced membrane damage and changed cellular structure. Collectively, the Mo2C-assisted ED demonstrated in the present study represents an attractive alternative to the traditional disinfection methods in combating the spread of antibiotic resistance.