摘要

       热带和温带地区的土壤被认为是人类驱动的获得性抗生素抗性（AR）遗传潜力的汇。相反，在大多数极性土壤中，获得的AR累积的可能性较小，为表征背景阻力和建立评价AR扩散的基准提供了平台。本文采用高通量qPCR和地球化学方法，对高北极斯瓦尔巴特江峡湾地区8个土壤类群中抗生素抗性基因（ARGs）和选择的移动遗传元素（MGEs）的丰度和多样性进行了定量研究。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），并显示出人类和野生动物对集群的潜在影响的梯度，如地球化学条件的改变和“外来”ARG丰度的增加（即外来的），包括blaNDM-1。受影响的团聚体表现出100倍高的总ARGs和MGEs，同时伴随着次生养分的增加，尤其是在北极土壤中，有效磷含量通常较低且有限。相比之下，受影响较小的岩群中的ARGs与当地的土壤岩性密切相关。该地区最可能的外源磷和外来arg来源是鸟类和其他野生动物鸟粪，通过当地人类粪便或直接运输和沉积传播。无论路径如何，高北极土壤中明显的外来ARGs和MGEs的积累是令人关注的，这突出了现在确定北极地区特征以建立追踪全球AR扩散的基准的重要性。

       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 bla_NDM-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?via%3Dihub