摘要

       土壤是抗生素抗性基因 (ARG) 的重要环境储存库，越来越多地将其视为环境污染物。评估与耐药机制的获得或转移相关的风险的方法仍然不完善。量化抗生素抗性基因的背景水平以及改变这些水平的因素是了解我们的环境抗性组的第一步。为实现这一目标，我们在 3 年内从拥有 30 年历史的冈瓦纳研究站附近的土壤中以及在南极洲特拉诺瓦湾新 Jang Bogo 研究站开发之前和开发期间的 4 年中收集了 62 个样本。这些站点分别反映了有限和更广泛的人类影响。具有 384 个针对抗生素抗性基因和移动遗传元件 (MGE) 的引物组的 qPCR 阵列用于检测和量化这些基因。共检测到 73 个 ARG 和 MGE，包括八个主要的抗生素抗性基因类别，但大多数处于非常低的水平。南极土壤似乎是 7 个 ARG 的常见储存库，因为它们存在于大多数样品中（42%–88%）。如果去除七个普遍存在的基因，则 MGEs 和 ARGs 的相对丰度之间存在相关性，更典型的是受污染地点。 ARG 含量与两个研究站的距离之间存在关系，在 Jang Bogo 站影响显着，尤其是在排除 7 个广泛分布的基因时；然而，ARG 的相对丰度在 4 年期间没有增加。淤泥、粘土、总有机碳和 SiO2 是与 ARG 丰度相关的主要土壤因子。总的来说，这项研究确定了人类活动和某些土壤特征与这些贫营养南极土壤中的抗生素抗性基因相关，并为未来的比较提供了 ARGs 和 MGEs 的基线。

       Soil is an important environmental reservoir of antibiotic resistance genes (ARGs), which are increasingly recognized as environmental contaminants. Methods to assess the risks associated with the acquisition or transfer of resistance mechanisms are still underdeveloped. Quantification of background levels of antibiotic resistance genes and what alters those is a first step in understanding our environmental resistome. Toward this goal, 62 samples were collected over 3 years from soils near the 30-year old Gondwana Research Station and for 4 years before and during development of the new Jang Bogo Research Station, both at Terra Nova Bay in Antarctica. These sites reflect limited and more extensive human impact, respectively. A qPCR array with 384 primer sets targeting antibiotic resistance genes and mobile genetic elements (MGEs) was used to detect and quantify these genes. A total of 73 ARGs and MGEs encompassing eight major antibiotic resistance gene categories were detected, but most at very low levels. Antarctic soil appeared to be a common reservoir for seven ARGs since they were present in most samples (42%–88%). If the seven widespread genes were removed, there was a correlation between the relative abundance of MGEs and ARGs, more typical of contaminated sites. There was a relationship between ARG content and distance from both research stations, with a significant effect at the Jang Bogo Station especially when excluding the seven widespread genes; however, the relative abundance of ARGs did not increase over the 4 year period. Silt, clay, total organic carbon, and SiO2 were the top edaphic factors that correlated with ARG abundance. Overall, this study identifies that human activity and certain soil characteristics correlate with antibiotic resistance genes in these oligotrophic Antarctic soils and provides a baseline of ARGs and MGEs for future comparisons.

https://pubs.acs.org/doi/abs/10.1021/acs.est.6b02863