Antibiotic resistance transmission risks in water after the disinfection with activated persulfate through Fe/C micro electrolysis and UVA/LED irradiation

Abstract

Recently, there has been increasing attention about the inactivation of antibiotic resistant bacteria (ARB) using activated persulfate (PS). However, little information could be found on antibiotic resistance (AR) transmission risks after ARB inactivation under activated PS. Batch experiments were conducted to investigate target ARB (E. coli K-12 carrying blaTEM, tetR and aphA) inactivation during the disinfection with activated PS using Fe/C micro electrolysis and UVA/LED irradiation, showing that ARB inactivation was 5.3 log reduction after 60 min of the disinfection with Fe/C activation of PS under acidic conditions (pH 5), which was larger than the one (4.7 log reduction) for the activated PS through UVA/LED. ARB inactivation mechanisms exploration implied that both O2•- and 1O2 were predominant reactive oxygen species (ROS) for ARB inactivation. There was more ARGs conjugation transfer frequency (2.0 ×10−4) after 20 min disinfection of activated PS with UVA/LED, compared with that (2.8 ×10−5) of the disinfection with Fe/C activation of PS. In contrast, AR transformation frequency after the disinfection by Fe/C activation of PS was slightly higher than the one after the disinfection by UVA/LED activation of PS, which was in line with profiles of intracellular ROS and ARB membrane permeability. Furthermore, ARB was completely inactivated after 40 min of the disinfection with the combination between UVA/LED and Fe/C for the activation of PS, indicating that the mentioned combination system could be feasible and desirable to block the risk of AR transmission in this study.