Department of Surface Waters-Research and Management, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland.
Group of Limnology and Environmental Geology, Institut F.-A. Forel, University of Geneva, Versoix, Switzerland.
ISME J. 2014 Jul;8(7):1381-90. doi: 10.1038/ismej.2014.8. Epub 2014 Mar 6.
Antibiotic-resistance genes (ARGs) are currently discussed as emerging environmental contaminants. Hospital and municipal sewage are important sources of ARGs for the receiving freshwater bodies. We investigated the spatial distribution of different ARGs (sul1, sul2, tet(B), tet(M), tet(W) and qnrA) in freshwater lake sediments in the vicinity of a point source of treated wastewater. ARG contamination of Vidy Bay, Lake Geneva, Switzerland was quantified using real-time PCR and compared with total mercury (THg), a frequently particle-bound inorganic contaminant with known natural background levels. Two-dimensional mapping of the investigated contaminants in lake sediments with geostatistical tools revealed total and relative abundance of ARGs in close proximity of the sewage discharge point were up to 200-fold above levels measured at a remote reference site (center of the lake) and decreased exponentially with distance. Similar trends were observed in the spatial distribution of different ARGs, whereas distributions of ARGs and THg were only moderately correlated, indicating differences in the transport and fate of these pollutants or additional sources of ARG contamination. The spatial pattern of ARG contamination and supporting data suggest that deposition of particle-associated wastewater bacteria rather than co-selection by, for example, heavy metals was the main cause of sediment ARG contamination.
抗生素耐药基因 (ARGs) 目前被认为是新兴的环境污染物。医院和城市污水是受纳淡水体中 ARGs 的重要来源。我们调查了处理后的废水点源附近淡水湖底泥中不同 ARGs（sul1、sul2、tet(B)、tet(M)、tet(W)和 qnrA）的空间分布。使用实时 PCR 定量了瑞士日内瓦湖 Vidy 湾的 ARG 污染情况，并将其与总汞 (THg) 进行了比较，总汞是一种经常与颗粒结合的无机污染物，具有已知的自然背景水平。利用地质统计学工具对湖底泥中调查污染物的二维制图表明，在污水处理排放点附近的总 ARG 和相对丰度比在偏远参考点（湖中心）测量的水平高出 200 倍，并随距离呈指数下降。不同 ARGs 的空间分布也呈现出类似的趋势，而 ARG 和 THg 的分布仅呈中度相关，表明这些污染物的传输和归宿存在差异，或者存在 ARG 污染的其他来源。ARG 污染的空间模式和支持数据表明，颗粒相关废水细菌的沉积而不是重金属等的共选择是底泥 ARG 污染的主要原因。
