摘要
      大气、废水和土壤是抗生素抗性基因（ARGs）的主要天然容器，但在冷冻温度期间，ARGs在上述阶段的分布和传播仍然很难实现。在这项研究中，在乳制品平均气温为−27°C至29°C期间，检测了来自5个人类相关点源的灰尘、废水和土壤相中的几种ARG。还探讨了影响因素（如VGT（细菌生物量）、HGT（intI1基因）、季节变化（非寒冷和寒冷季节）、环境阶段和点源）。结果显示，废水相含有最高的总靶向ARGs（每16S rRNA基因拷贝2.00×10−2个基因拷贝）。Bray-Curtis距离的主坐标分析（PCoA）表明，灰尘相中选定的ARG可能来源于废水和土壤相。养猪场是ARGs的潜在热点，在灰尘（5.34×10−1）和废水（3.59×10−2）相中，目标ARGs总量的相对丰度最高。季节变化可能影响ARGs在三个阶段的浓度，sul基因（sul1，sul2）和erm基因（ermB，ermC）相对丰度的百分比在非寒冷季节（41.06%）和寒冷季节（42.62%）分别呈现较高的比例。16S rRNA、intI1和所选ARGs之间的正相关性分别在寒冷季节和非寒冷季节的灰尘和废水阶段增强，这表明垂直基因转移（VGT）和intI1介导的水平基因转移（HGT）随自然阶段和季节而变化。这项研究强调了环境阶段和季节在大范围温度下对ARG传播的关键作用。
Abstract
Atmosphere, wastewater, and soil are the main natural receptacles of antibiotic resistance genes (ARGs), but the profiles and transmission of ARGs across the above-mentioned phases during freezing temperatures remain poorly realized. In this study, several ARGs in dust, wastewater and soil phases from 5 human-associated point-sources during dairy mean air temperature from −27 °C to 29 °C were examined. The factors (e.g., VGT (bacteria biomass), HGT (intI1 gene), seasonal variations (non-cold and cold seasons), environmental phases, and point-sources) were also explored. Results showed the wastewater phase harbored the highest total targeted ARGs (2.00 × 10−2 gene copies per 16S rRNA gene copies). Principal coordinate analysis (PCoA) with Bray-Curtis distance indicated that the selected ARGs in the dust phase might originate from the wastewater and soil phases. The pig farm was a potential hotpot of ARGs, which carried the highest relative abundances of total targeted ARGs in the dust (5.34 × 10−1) and wastewater phases (3.59 × 10−1). Seasonal variations potentially influenced the concentration of ARGs among three phases, the percentages of sul genes (sul1, sul2) and erm gene (ermB, ermC) relative abundances presented higher proportions in the non-cold season (41.06%) and cold season (42.62%), respectively. The positive correlations between 16S rRNA, intI1, and selected ARGs strengthened in dust and wastewater phases during the cold season and non-cold season, respectively, which hinted vertical gene transfer (VGT) and intI1-mediated horizontal gene transfer (HGT) varied with natural phases and seasons. This study highlights the critical roles of environmental phases and seasons in huge ranges of temperatures for ARG dissemination.

https://www.sciencedirect.com/science/article/abs/pii/S0959652622047382