摘要

       地下水是必不可少的公共和饮用水供应源，保护地下水是全球政策的目标。在这里，我们调查了距市区不同距离的地下水环境中抗生素残留、抗生素抗性基因 (ARG)、移动遗传元件 (MGE) 和微生物污染的存在和流行情况。抗生素浓度范围从低于检测限到 917 ng/L，甲氧苄啶、大环内酯和磺胺是最丰富的抗生素类别。 qPCR共检测到11个ARG（氨基糖苷、β-内酰胺、氯霉素、大环内酯-林可酰胺-链霉菌素B-MLSB、磺胺和四环素）、1个防腐基因和2个MGE，相对丰度为6.61×10− 7 到 2.30×10−1 拷贝/16S rRNA 基因拷贝。 ARGs 和 MGEs 在调查的地下水环境中广泛存在，不仅在城市，而且在偏远地区都有增加的丰度。观察到了不同的细菌群落概况，在受影响较小的地区，β变形菌和拟杆菌的流行率较高，而受污染地下水中厚壁菌门的流行率较高。增加的物种多样性、不同的系统发育组成以及可能存在的粪便和/或致病细菌的综合特征可能表明不同类型的污染。确定了地下水细菌群落内 ARG、MGE 和特定分类群之间的显着相关性，揭示了抗性类型的潜在宿主。尽管无法确定通用标记基因，但确定了 int1、qacEΔ1 和 sulI 基因（人为污染的代理组）与 tetC、tetO、tetW 抗性基因的共同选择。由于观察到 tet 组遵循本研究中调查的地下水样品的环境污染模式，我们的结果强烈支持这组基因作为人类影响的环境示踪剂的提议。总体而言，本研究调查了地下水栖息地中的几种新兴污染物，这些污染物可能包括在监测计划中，以便采取进一步的监管和保护措施。

       Groundwater is an indispensable source of public and drinking water supply, and protection of groundwater is the goal of global policy. Here, we investigated the existence and prevalence of antibiotic residues, antibiotic resistance genes (ARG), mobile genetic elements (MGE) and microbial contamination in groundwater environments at different distances from urban areas. Antibiotic concentrations range from below the detection limit to 917 ng/L. Trimethoprim, macrolide and sulfonamide are the most abundant antibiotic categories. A total of 11 ARGs (aminoglycosides, β-lactam, chloramphenicol, macrolide-lincosamide-streptomycin B-MLSB, sulfa and tetracycline), 1 antiseptic gene and 2 MGE were detected by qPCR, The relative abundance ranges from 6.61×10−7 to 2.30×10−1 copy/16S rRNA gene copy. ARGs and MGEs are widely present in the surveyed groundwater environment, not only in cities, but also in remote areas with increased abundance. Different bacterial community profiles were observed. In less affected areas, the prevalence of beta-proteobacteria and Bacteroides is higher, while the prevalence of Firmicutes in contaminated groundwater is higher. Increased species diversity, different phylogenetic composition, and possible combined features of feces and/or pathogenic bacteria may indicate different types of pollution. The significant correlation between ARG, MGE and specific taxa within the groundwater bacterial community was determined, revealing the potential host of resistance types. Although the universal marker genes could not be determined, the co-selection of int1, qacEΔ1 and sulI genes (a proxy group for human pollution) and tetC, tetO, and tetW resistance genes was determined. Since it is observed that the tet group follows the environmental pollution pattern of the groundwater samples investigated in this study, our results strongly support the proposal of this group of genes as an environmental tracer of human influence. Overall, this study investigated several emerging pollutants in groundwater habitats, and these pollutants may be included in the monitoring plan for further supervision and protection measures.

https://www.sciencedirect.com/science/article/abs/pii/S0269749117343543