摘要

     水库在地表水资源的控制和管理中起着至关重要的作用。然而，在水库中长时间的水滞留可能会增加抗药性基因（ARGs）的储存和积累。水库中中抗生素耐药性的完整情况和潜在健康风险在很大程度上是未知的。本研究采用宏基因组测序方法，对我国最大水库之一丹江口水库不同季节水、沉积物的抗生素抗性进行了研究。在24个水体和18个沉积物样品中，共检测到20种ARG亚型436个，平均每个细胞的ARG亚型丰度为0.138个拷贝。沉积物中总的ARG丰度高于水中，水中和沉积物中的主要ARG类型分别为杆菌肽和万古霉素抗性基因。枯水期总的ARG丰度高于丰水期，不同季节间水体中的ARG亚型组成差异显著，而沉积物中的ARG亚型组成差异不显著。水体中潜在的水平基因转移频率高于沉积物中的水平基因转移频率，水体中的ARGs主要来源于水库上游沉积物。宏基因组鉴定出14株大肠杆菌、肺炎克雷伯菌、铜绿假单胞菌等携带ARG的病原菌，其中3株携带毒力因子。总体而言，丹江口水库枯水期水体中抗药性对公众健康的潜在危害高于丰水期。在此基础上，提出了水库水安全管理的对策，包括泥沙控制和病原菌监测。

     Reservoirs play a vital role in the control and management of surface water resources. However, the long water residence time in the reservoir potentially increases the storage and accumulation of antibiotic resistant genes (ARGs). The full profiles and potential health risks of antibiotic resistomes in reservoirs are largely unknown. In this study, we investigated the antibiotic resistomes of water and sediment during different seasons in the Danjiangkou Reservoir, which is one of the largest reservoirs in China, using a metagenomic sequencing approach. A total of 436 ARG subtypes belonging to 20 ARG types were detected from 24 water and 18 sediment samples, with an average abundance of 0.138 copies/cell. The overall ARG abundance in the sediment was higher than that in the water, and bacitracin and vancomycin resistance genes were the predominant ARG types in the water and sediment, respectively. The overall ARG abundance in the dry season was higher than that in the wet season, and a significant difference in ARG subtype compositions was observed in water, but not in the sediment, between the different seasons. The potential horizontal gene transfer frequency in the water was higher than that in the sediment, and the ARGs in water mainly came from the sediment upstream of the reservoir. The metagenomic assembly identified 14 contigs as ARG-carrying pathogens including Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, and 3 of 14 carried virulence factors. Overall, the potential public health risks posed by resistomes in the water of the Danjiangkou Reservoir were higher in the dry season than in the wet season. Based on these results, strategies including sediment control and pathogen monitoring are suggested for water safety management in drinking water reservoirs.

     https://www.sciencedirect.com/science/article/pii/S0160412019327941