Molybdenum carbide changes the abundance of antibiotic resistance genes and bacterial communities in bioelectrocatalytic systems treating wastewater contaminated by tetracycline

Although the superiority of stainless steel mesh-based molybdenum carbide (SS-Mo2C)-assisted bioelectrocatalytic systems (BECSs) for the degradation of tetracycline (TC) has been shown, the effect on antibiotic resistance gene (ARG) abundance in such systems is still unclear. On this basis, we further explored the effects of a BECS on microbial communities by changing different coupling modes and chemical oxygen demand (COD) concentrations. The results of network analysis showed that the relative abundance of host bacteria in the BECS (relative abundance 54.81 %) was significantly higher than that of the biological system (relative abundance 25.98 %). The changes in bacterial community structure and the high correlation between the integron intI1 and ARGs suggested that both horizontal gene transfer and a shift in potential host bacteria were dominant factors affecting the abundance of ARGs. These results provided evidence for the effects of the SS-MO2C electrode on the control of ARG abundance in BECSs.