The inactivation of antibiotic-resistant bacteria and the damage of antibiotic-resistant genes using an electrified carbon nanotube membrane-NaClO system

Abstract

The inactivation of antibiotic-resistant bacteria (ARB) and damage of antibiotic resistance genes (ARGs) in aquatic environments have become major concerns worldwide in controlling the rapid spread of antibiotic resistance. In this study, an electrified carbon nanotube membrane (ECM) was combined with chlorine disinfection (denoted as ECM-NaClO system) to treat the sulphonamide resistance bacteria (HLS-6) and tetracycline resistance bacteria (TOP-10F) in water samples. The ECM-NaClO system effectively inactivated the HLS-6 and TOP-10F by damaging the cell membrane and increasing amounts of intracellular reactive oxygen species (ROS). In addition, the absolute abundances of the sulphonamide resistance gene (sul1) and tetracycline resistance gene (tetA) in the effluent decreased by 3.5 and 1.7 logs, respectively. Furthermore, the absolute abundance of mobile genetic elements (intI1) decreased by 4.1–4.7 logs. The ROS probe compound degradation and quenching experiments revealed that the •OH generated via the 2-electron oxygen reduction reaction played a dominant role in the damage of sul1 gene, while •O2– generated through the activation of NaClO was a key contributor to the damage of tetA gene. Hence, the ECM-NaClO system is a potential method to inactivate ARB and damage ARGs in water and sewage treatment plants.