摘要

      环境中的抗生素耐药基因（ARGs）受到人为活动的促进，对人类健康造成潜在的危害。然而，关于原始环境和人为环境中抗生素耐药性的大规模定量数据仍有待于探索。在这里，我们使用全基因组分析来研究原始环境和肠道相关环境中ARG谱及其潜在细菌宿主的共享和差异。我们发现肠道相关环境中总ARGs的含量显著高于原始环境（P<0.001）。耐药基因mcr-1和tetX在肠道相关环境中的丰度较高（分别为4.57拷贝/Gb和3.39拷贝/Gb），提示人为抗生素对ARG的污染。基于亚基因组组装的宿主跟踪分析表明，大肠杆菌、类杆菌和梭状芽孢杆菌是ARGs在肠道相关环境中的主要宿主，而交替单胞菌、弧菌和蛋白细菌是ARGs在原始环境中的主要宿主。我们首先使用全基因组分析描述了不同环境中ARG宿主的广泛多样性。我们的结果揭示了在肠道相关环境和原始环境中，ARGs及其宿主在不同微生物生态位中的异质分布。

        Antibiotic resistance genes (ARGs) in the environment are promoted by anthropogenic activities, which cause potential risks to human health. However, large-scale quantitative data on antibiotic resistome from the pristine and anthropogenic environments remains largely unexplored. Here, we used metagenome-wide analysis to investigate the share and divergence in ARG profiles and their potential bacterial hosts between the pristine and gut-associated environments. We found that the abundance of total ARGs in gut-associated environments was significantly higher than the pristine environments (P < 0.001). The mcr-1 and tetX, the genes resistant to the last resort antibiotics (colistin and tigecycline, respectively), were in high abundance (4.57 copies/Gb and 3.39 copies/Gb, respectively) in gut-associated environments, suggesting the ARG pollution caused by anthropogenic antibiotics. Metagenomic assembly-based host-tracking analysis identified Escherichia, Bacteroides, and Clostridium as the predominant bacterial hosts of ARGs in gut-associated environments, while Alteromonas, Vibrio, and Proteobacteria as the predominant bacterial hosts of ARGs in pristine environments. We first described the broad diversity of ARG hosts in different environments using metagenome-wide analysis. Our results revealed the heterogeneous distribution of ARGs and their hosts among different microbial niches in gut-associated environments and the pristine environments.

         https://www.sciencedirect.com/science/article/pii/S0160412018331660?via%3Dihub