摘要

       众所周知，热带和温带地区的土壤是人为驱动的获得性抗生素抗性 (AR) 遗传潜力的汇。相比之下，在大多数极地土壤中获得的 AR 积累的可能性较小，为表征背景电阻和建立评估 AR 传播的基准提供了一个平台。在这里，高通量 qPCR 和地球化学用于量化高北极斯瓦尔巴群岛 Kongsfjorden 地区八个土壤簇中抗生素抗性基因 (ARG) 和选定的移动遗传元件 (MGE) 的丰度和多样性。相对 ARG 水平的范围超过两个数量级（10-6 到 10-4 拷贝/16S rRNA 基因拷贝），并显示出跨集群的潜在人类和野生动物影响梯度，这可以通过地球化学条件改变和“外来”ARG 增加来证明丰度（即异地），包括blaNDM-1。受影响的集群表现出高 100 倍的总 ARG 和 MGE，同时次生养分升高，尤其是在北极土壤中通常较低且有限的有效磷。相比之下，受影响较小的簇中的 ARG 与当地土壤岩性密切相关。该地区最可能的外源磷和外源 ARG 来源是鸟类和其他野生动物鸟粪，通过当地人类排泄物或直接运输和沉积传播。不管途径如何，在北极高地土壤中明显的外源 ARG 和 MGE 的积累令人担忧，这突出了现在表征北极站点以建立跟踪 AR 在世界各地传播的基准的重要性。

       Soils in tropical and temperate locations are known to be a sink for the genetic potential of anthropogenic-driven acquired antibiotic resistance (AR). In contrast, accumulation of acquired AR is less probable in most Polar soils, providing a platform for characterizing background resistance and establishing a benchmark for assessing AR spread. Here, high-throughput qPCR and geochemistry were used to quantify the abundance and diversity of both antibiotic resistance genes (ARGs) and selected mobile genetic elements (MGEs) across eight soil clusters in the Kongsfjorden region of Svalbard in the High Arctic. Relative ARG levels ranged by over two orders of magnitude (10−6 to 10−4 copies/16S rRNA gene copy), and showed a gradient of potential human and wildlife impacts across clusters as evidenced by altered geochemical conditions and increased “foreign” ARG abundances (i.e., allochthonous), including blaNDM-1. Impacted clusters exhibited 100× higher total ARGs and MGEs in tandem with elevated secondary nutrients, especially available P that is typically low and limiting in Arctic soils. In contrast, ARGs in less-impacted clusters correlated strongly to local soil lithology. The most plausible source of exogenous P and allochthonous ARGs in this region is bird and other wildlife guano, disseminated either by local human wastes or via direct carriage and deposition. Regardless of pathway, accumulation of apparent allochthonous ARGs and MGEs in High Arctic soils is concerning, highlighting the importance of characterizing Arctic sites now to establish benchmarks for tracking AR spread around the world.

https://www.sciencedirect.com/science/article/pii/S016041201832587X