Beltrán de Heredia Irene, Garbisu Carlos, Alkorta Itziar, Urra Julen, González-Gaya Belén, Ruiz-Romera Estilita
Department of Chemical and Environmental Engineering, University of the Basque Country (UPV/EHU), Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain.
Department of Conservation of Natural Resources, NEIKER-Basque Institute of Agricultural Research and Development, Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park, P812, 48160, Derio, Spain.
Environ Pollut. 2023 Feb 15;319:120883. doi: 10.1016/j.envpol.2022.120883. Epub 2022 Dec 23.
There is a growing concern about the risk of antibiotic resistance emergence and dissemination in the environment. Here, we evaluated the spatio-seasonal patterns of the impact of wastewater treatment plant (WWTP) effluents on antibiotic resistance in river sediments. To this purpose, sediment samples were collected in three river basins affected by WWTP effluents in wet (high-water period) and dry (low-water period) hydrological conditions at three locations: (i) upstream the WWTPs; (ii) WWTP effluent discharge points (effluent outfall); and (iii) downstream the WWTPs (500 m downriver from the effluent outfall). The absolute and relative abundances of 9 antibiotic resistance genes (ARGs), 3 mobile genetic element (MGE) genes, and 4 metal resistance genes (MRGs) were quantified in sediment samples, as well as a variety of physicochemical parameters, metal contents, and antibiotic concentrations in both sediment and water samples. In sediments, significantly higher relative abundances of most genes were observed in downstream vs. upstream sampling points. Seasonal changes (higher values in low-water vs. high-water period) were observed for both ARG absolute and relative abundances in sediment samples. Chemical data revealed the contribution of effluents from WWTPs as a source of antibiotic and metal contamination in river ecosystems. The observed positive correlations between ARG and MGE genes relative abundances point out to the role of horizontal gene transfer in antibiotic resistance dissemination. Monitoring plans that take into consideration spatio-temporal patterns must be implemented to properly assess the environmental fate of WWTP-related emerging contaminants in river ecosystems.
人们越来越关注环境中抗生素耐药性出现和传播的风险。在此，我们评估了污水处理厂（WWTP）废水对河流沉积物中抗生素耐药性影响的时空模式。为此，在三个受污水处理厂废水影响的流域，于潮湿（高水位期）和干燥（低水位期）水文条件下的三个地点采集沉积物样本：（i）污水处理厂上游；（ii）污水处理厂废水排放点（废水排放口）；以及（iii）污水处理厂下游（废水排放口下游500米处）。对沉积物样本中的9种抗生素抗性基因（ARG）、3种移动遗传元件（MGE）基因和4种金属抗性基因（MRG）的绝对丰度和相对丰度进行了定量分析，同时还对沉积物和水样中的各种理化参数、金属含量及抗生素浓度进行了测定。在沉积物中，与上游采样点相比，下游采样点大多数基因的相对丰度显著更高。在沉积物样本中，抗生素抗性基因的绝对丰度和相对丰度均呈现季节性变化（低水位期的值高于高水位期）。化学数据揭示了污水处理厂废水作为河流生态系统中抗生素和金属污染来源的贡献。抗生素抗性基因和移动遗传元件基因相对丰度之间观察到的正相关表明水平基因转移在抗生素耐药性传播中的作用。必须实施考虑时空模式的监测计划，以正确评估河流生态系统中与污水处理厂相关的新兴污染物的环境归宿。
