摘要

       细菌对抗生素和重金属的耐药性通常是相关联的，这表明暴露于重金属可能会选择赋予抗生素耐药性的细菌组合。然而，从长期来看，重金属引起的抗生素耐药性变化缺乏明确的证据。在这里，我们使用高容量定量 PCR 阵列来研究广谱抗生素抗性基因 (ARG) 对两种对比农业土壤中 4-5 年铜污染 (0-800 mg kg-1) 的反应。总共在红色和潮土中分别检测到 157 和 149 种独特的 ARG，其中多药和 β-内酰胺是最主要的 ARG 类型。在中等铜浓度（100-200 mg kg-1）的红壤和高铜浓度（400-800 mg kg-1）的潮土中观察到最高的 ARG 多样性和丰度。总ARGs和几种ARG类型的丰度与移动遗传元素（MGEs）呈显着正相关，表明ARGs在铜污染土壤中的移动潜力。网络分析揭示了 ARG 和微生物分类群之间的显着共现模式，表明 ARG 与细菌群落之间存在很强的关联。结构方程模型表明，铜污染对 ARG 模式的显着影响主要是由细菌群落组成和 MGE 的变化驱动的。我们的研究结果提供了基于现场的证据，表明长期铜污染显着改变了环境抗生素耐药性的多样性、丰度和流动潜力，并警告了 ARG 在重金属污染环境中传播的未被察觉的风险。

       Bacterial resistance to antibiotics and heavy metals are frequently linked, suggesting that exposure to heavy metals might select for bacterial assemblages conferring resistance to antibiotics. However, there is a lack of clear evidence for the heavy metal-induced changes of antibiotic resistance in a long-term basis. Here, we used high-capacity quantitative PCR array to investigate the responses of a broad spectrum of antibiotic resistance genes (ARGs) to 4–5 year copper contamination (0–800 mg kg−1) in two contrasting agricultural soils. In total, 157 and 149 unique ARGs were detected in the red and fluvo-aquic soil, respectively, with multidrug and β-lactam as the most dominant ARG types. The highest diversity and abundance of ARGs were observed in medium copper concentrations (100–200 mg kg−1) of the red soil and in high copper concentrations (400–800 mg kg−1) of the fluvo-aquic soil. The abundances of total ARGs and several ARG types had significantly positive correlations with mobile genetic elements (MGEs), suggesting mobility potential of ARGs in copper-contaminated soils. Network analysis revealed significant co-occurrence patterns between ARGs and microbial taxa, indicating strong associations between ARGs and bacterial communities. Structural equation models showed that the significant impacts of copper contamination on ARG patterns were mainly driven by changes in bacterial community compositions and MGEs. Our results provide field-based evidence that long-term Cu contamination significantly changed the diversity, abundance and mobility potential of environmental antibiotic resistance, and caution the un-perceived risk of the ARG dissemination in heavy metal polluted environments.

https://sfamjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1462-2920.13370