摘要

       在加拿大北极地区，通常的做法是将市政废水排放到苔原湿地。抗生素抗性细菌及其包含的抗生素抗性基因 (ARG) 可能存在于市政废水中，并且对北极环境中废水中的 ARG 缺乏了解。这项研究是关于受北极社区人为废水源影响的苔原湿地生态系统中 ARG 的命运的。 2016 年夏季，对加拿大努纳武特的 Sanikiluaq 和 Naujaat 因纽特人社区的两个湿地进行了研究。在湿地的春季和夏末期间从土壤和水中提取基因组 DNA，以及一套九个临床相关的 ARG（sul1、sul2、mecA、vanA、qnrS、ermB、tetO、blaTEM、blaCTX-M），使用定量聚合酶链反应 (qPCR) 分析整合子基因 (int1)。水文和水质测量与微生物取样一起进行。基因靶标始终存在于废水中，并且遍及两个湿地，除了 vanA 和 mecA。由于水力停留时间短（<2 天），春季新鲜期间 ARG 的浓度更高，这与处理性能下降相吻合。未受影响的湿地环境抵抗组在 Naujaat 的水中检测到 int1、sul1、sul2、blaCTX-M，在 Sanikiluaq 的土壤中检测到 sul1、qnrS 和 tetO。一级速率常数变化很大并且特定于基因靶标。在受城市污水影响的苔原湿地中，ARG 的浓度高于基线参考点，水文条件对其空间分布和水平有很大影响。

       In the Canadian Arctic, it is common practice to discharge municipal wastewater into tundra wetlands. Antibiotic resistant bacteria and the antibiotic resistance genes (ARGs) they contain can be present in municipal wastewater and there is a scarcity of knowledge on ARGs in wastewater in Arctic environments. This study was initiated on the fate of ARGs in tundra wetland ecosystems impacted by anthropogenic wastewater sources in Arctic communities. In the summer season of 2016, two wetlands were studied in the Inuit communities of Sanikiluaq and Naujaat in Nunavut, Canada. Genomic DNA was extracted from both soil and water during the spring freshet and late summer in the wetlands, and a suite of nine clinically relevant ARGs (sul1, sul2, mecA, vanA, qnrS, ermB, tetO, blaTEM, blaCTX-M), and an integron gene (int1) were analyzed using quantitative polymerase chain reaction (qPCR). Hydrological and water quality measurements were conducted in conjunction with the microbiological sampling. Gene targets were consistently present in the wastewater, and throughout both wetlands, except for vanA and mecA. Concentrations of ARGs were greater during the spring freshet, due to short hydraulic retention times (<2 days), which coincided with decreased treatment performance. The environmental resistome in un-impacted wetlands had above detection limit concentrations of int1, sul1, sul2, blaCTX-M in water in Naujaat, and sul1, qnrS and tetO in soil in Sanikiluaq. First-order rate constants were widely variable and specific to the gene target. ARGs were present in concentrations elevated above baseline reference sites in tundra wetlands influenced by municipal wastewater, and hydrological conditions had a large impact on their spatial distribution and levels.

https://www.sciencedirect.com/science/article/abs/pii/S0048969718321545