SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China.
School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Sci Total Environ. 2020 May 1;715:136975. doi: 10.1016/j.scitotenv.2020.136975. Epub 2020 Jan 28.
Dissemination of antibiotic resistance genes (ARGs) in the water environment has become an increasing concern. There have been many reports on ARGs in surface water, but little is known about ARGs in groundwater. In this study, we investigated the profiles and abundance of ARGs in groundwater in comparison with those in surface water of Maozhou River using high-throughput quantitative PCR (HT-qPCR). Totally 127 ARGs and 10 MGEs were detected by HT-qPCR, and among them the sulfonamides, multidrug and aminoglycosides resistance genes were the dominant ARG types. According to the results of HT-qPCR, 18 frequently detected ARGs conferring resistance to 6 classes of antibiotics and 3 MGEs were further quantified by qPCR in the wet season and dry season. The absolute abundance ranged from 1.23 × 10 to 8.89 × 10 copies/mL in wet season and from 8.50 × 10 to 2.65 × 10 copies/mL in the dry season, with sul1 and sul2 being the most abundant ARGs. The absolute abundance of ARGs and MGEs has no significant difference between the wet season and dry season while the diversity of ARGs in the dry season was higher than that in the wet season (p < 0.05). Totally 141 and 150 ARGs were detected in the water and sediments of Maozhou River, respectively. A total of 116 ARGs were shared among the groundwater, river water, and sediment, which accounted for 67.1% of all detected genes. Redundancy analysis further demonstrated that the environmental factors contributed 70.7% of the total ARG variations. The findings of large shared ARGs, abundant Total Coliforms and large wastewater burden in the groundwater provide a clear evidence that anthropogenic activities had a significant impact on groundwater.
抗生素耐药基因（ARGs）在水环境中的传播引起了越来越多的关注。已有许多关于地表水抗生素耐药基因的报道，但对地下水抗生素耐药基因的了解甚少。在这项研究中，我们使用高通量定量 PCR（HT-qPCR）比较了毛洲河地表水和地下水抗生素耐药基因的分布和丰度。通过 HT-qPCR 共检测到 127 种抗生素耐药基因和 10 种移动遗传元件（MGEs），其中磺胺类、多药和氨基糖苷类耐药基因是主要的抗生素耐药基因类型。根据 HT-qPCR 的结果，在湿季和干季，我们通过 qPCR 进一步定量了 18 种经常检测到的对抗生素 6 类抗生素和 3 种 MGEs 具有抗性的抗生素耐药基因。在湿季，抗生素耐药基因的绝对丰度范围为 1.23×10-8 至 8.89×10-8 拷贝/mL，在干季，抗生素耐药基因的绝对丰度范围为 8.50×10-8 至 2.65×10-8 拷贝/mL，其中 sul1 和 sul2 是最丰富的抗生素耐药基因。湿季和干季抗生素耐药基因和 MGEs 的绝对丰度没有显著差异，而干季抗生素耐药基因的多样性高于湿季（p<0.05）。在毛洲河的水和沉积物中分别检测到 141 种和 150 种抗生素耐药基因。地下水、河水和沉积物中共检测到 116 种抗生素耐药基因，占所有检测到的基因的 67.1%。冗余分析进一步表明，环境因素对总抗生素耐药基因变异的贡献率为 70.7%。地下水中大量共享的抗生素耐药基因、丰富的总大肠菌群和大量的废水负荷为人类活动对地下水的显著影响提供了明确的证据。
