title: High-throughput profiling of antibiotic resistance genes in drinking water treatment plants and distribution systems.
abstract: Antibiotic resistance genes (ARGs) are present in surface water and often cannot be completely eliminated by drinking water treatment plants (DWTPs). Improper elimination of the ARG-harboring microorganisms contaminates the water supply and would lead to animal and human disease. Therefore, it is of utmost importance to determine the most effective ways by which DWTPs can eliminate ARGs. Here, we tested water samples from two DWTPs and distribution systems and detected the presence of 285 ARGs, 8 transposases, and intI-1 by utilizing high-throughput qPCR. The prevalence of ARGs differed in the two DWTPs, one of which employed conventional water treatments while the other had advanced treatment processes. The relative abundance of ARGs increased significantly after the treatment with biological activated carbon (BAC), raising the number of detected ARGs from 76 to 150. Furthermore, the final chlorination step enhanced the relative abundance of ARGs in the finished water generated from both DWTPs. The total enrichment of ARGs varied from 6.4-to 109.2-fold in tap water compared to finished water, among which beta-lactam resistance genes displayed the highest enrichment. Six transposase genes were detected in tap water samples, with the transposase gene TnpA-04 showing the greatest enrichment (up to 124.9-fold). We observed significant positive correlations between ARGs and mobile genetic elements (MGEs) during the distribution systems, indicating that transposases and intI-1 may contribute to antibiotic resistance in drinking water. To our knowledge, this is the first study to investigate the diversity and abundance of ARGs in drinking water treatment systems utilizing high-throughput qPCR techniques in China.
authors.affiliation: Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Like
authors.initials: L
authors.lastname: Xu
authors.affiliation: Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
authors.forename: Weiying
authors.initials: W
authors.lastname: Ouyang
authors.affiliation: Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Yanyun
authors.initials: Y
authors.lastname: Qian
authors.affiliation: Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Su
authors.affiliation: Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Su
authors.affiliation: Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China. Electronic address: chen_hong@zju.edu.cn.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis*; D002681:China; D060766:Drinking Water / Q000032:analysis / Q000382:microbiology*; D004352:Drug Resistance, Microbial / Q000235:genetics*; D004784:Environmental Monitoring / Q000379:methods; D005798:Genes, Bacterial; D006801:Humans; D060888:Real-Time Polymerase Chain Reaction; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D060766:Drinking Water; D014874:Water Pollutants, Chemical
keywords: Antibiotic resistance genes; Drinking water treatment plants; High-throughput qPCR; Tap water