摘要

       重金属诱导的抗生素抗性基因 (ARG) 的共选择已成为一个新兴的环境问题。土壤动物的内脏在陆地生态系统中提供了一个独特的栖息地，并拥有各种微生物。然而，重金属对土壤动物肠道相关 ARG 的影响知之甚少。在本研究中，弹跳虫与四种重金属（Zn、Cu、Cd 和 Cr）和一种抗生素（土霉素）一起培养，以研究它们对肠道相关 ARG 的影响。高通量定量 PCR 和 16S rRNA 基因扩增子测序用于检查由金属和抗生素引起的肠道相关 ARG 和微生物组成的变化。结果表明，重金属单独诱导了弹尾虫肠道中 ARGs 的共同选择，但其作用弱于土霉素的选择。当Zn或Cu与土霉素一起存在时，化合物之间有很强的协同作用，这增加了弹尾虫肠道中ARG的选择。此外，冗余分析显示肠道微生物群和移动遗传元件（MGE）与 ARG 组成显着相关。这些结果扩展了我们对重金属对土壤食物网中 ARGs 扩散影响的理解。

       Heavy metal induced co-selection of antibiotic resistance genes (ARGs) has become an emerging environmental issue. The guts of soil fauna offer a unique habitat in the terrestrial ecosystem and harbor a variety of microorganisms. However, the effects of heavy metals on the gut-associated ARGs of soil fauna are poorly understood. In the present study, collembolans were cultivated with four types of heavy metals (Zn, Cu, Cd, and Cr) and one antibiotic (oxytetracycline), to investigate their impact on the gut-associated ARGs. High-throughput quantitative PCR and 16S rRNA gene amplicon sequencing were used to examine changes in the gut-associated ARGs and microbial composition caused by the metals and antibiotic. The results showed that heavy metals alone induced co-selection of ARGs in the collembolan gut, but the effects were weaker than selection by oxytetracycline. When Zn or Cu was present together with oxytetracycline, there was a strong synergistic effect between the compounds, which increased the selection of ARGs in the collembolan guts. Furthermore, redundancy analysis revealed that the gut microbiota and mobile genetic elements (MGEs) were significantly correlated with the ARG composition. These results extend our understanding on effects of heavy metals on the dispersal of ARGs in the soil food web.

https://www.sciencedirect.com/science/article/abs/pii/S0048969719323435