Effects of Chlorine Dioxide Disinfection on the Profile of the Super Antibiotic Resistance Genes in a Wastewater Treatment Plant

In order to study the effects of chlorine dioxide (ClO2) disinfection on the super antibiotic resistance genes (SARGs), the final effluents before and after chlorine dioxide were sampled throughout one year in a wastewater treatment plant (WWTP). The bacteria and extracellular nucleic acid were collected using microporous membrane filtration and nucleic acid adsorption particles, respectively. A total of 9 SARGs was detected through a quantitative real-time polymerase chain reaction (qPCR). The results revealed that both intracellular and extracellular NDM-1, MCR-1, and MEC-A could be positively detected in the samples. Overall, ClO2 disinfection enhanced the relative abundance of the iSARGs (P<0.05), exhibiting a seasonal pattern, and increasing in the spring, summer, and autumn. In spring, it improved the most, up to twice the abundance. No SARGs were detected positive in the winter, either intracellularly or extracellularly. There was no significant variation in the concentrations of eSARGs before and after ClO2 disinfection. Therefore, ClO2 disinfection cannot effectively remove iSARGs and eSARGs in the final effluent from the WWTP.