摘要

    重金属已被认为是驱动抗生素耐药性演变和发展的潜在因素。但是，目前尚不清楚镉（Cd）和砷（As）对抗生素抗性基因（ARGs）的流行和分布的相对影响。我们使用高通量定量PCR研究了镉和砷对45种重金属污染的稻田土壤中ARGs的共选作用。在所有样品中共检测到119个ARG和9个移动遗传元件（MGE）。回归分析表明，单一污染指数（PIAs和PICd）和Nemerow综合污染指数（NIPI）与ARGs均具有显着正相关（P <0.05），表明Cd和As对ARGs分布具有共选作用。在网络分析中，细菌类群与不同ARG之间的显着相关性揭示了ARG的潜在宿主。结构方程模型表明，砷对ARGs的影响强于Cd。通过强烈影响细菌的丰度，镉和砷可间接影响ARGs的分布。总体而言，这项研究扩展了我们对水稻土中ARGs中Cd和As的共选知识，对评估水稻土中ARGs的潜在风险具有重要意义。

    Heavy metals have been recognized as potential factors driving the evolution and development of antibiotic resistance. However, the relative effects of cadmium (Cd) and arsenic (As) on the prevalence and distribution of antibiotic resistance genes (ARGs) remain unclear. We investigated the co-selection effects of Cd and As on ARGs in 45 paddy soils polluted by heavy metals, using high-throughput quantitative PCR. A total of 119 ARGs and 9 mobile genetic elements (MGEs) were detected in all samples. Regression analysis showed that the single pollution index (PIAs and PICd) and Nemerow integrated pollution index (NIPI) both had significant and positive correlations with ARGs (P <  0.05), indicating the co-selective effects of Cd and As on ARGs distribution. The significant correlations between bacterial taxa and different ARGs in network analysis revealed potential hosts of ARGs. Structural equation models indicated that the effects of As on ARGs were stronger than that of Cd. The profile of ARGs could be impacted by Cd and As indirectly by strongly affecting the bacterial abundance. Overall, this study extended our knowledge about the co-selection of Cd and As on ARGs in paddy soil, and had important implications for assessing the potential risks of ARGs in paddy soils.

    https://www.sciencedirect.com/science/article/abs/pii/S0304389419317923