摘要

  市政垃圾渗滤液是（纳米）微塑料 (N/MP) 和抗生素抗性基因 (ARG) 的巨大水库。 N/MPs 具有影响细菌生长和细菌群落组成的能力，这可能会进一步影响 ARGs 在环境中的传播。为了推断这两种新兴污染物之间的相互作用，我们研究了渗滤液中 ARG 水平随暴露于不同尺寸的 N/MP 的变化。结果表明，ARGs 在 N/MPs 暴露组中富集，尤其是在 200-500 nm MP 组中。值得注意的是，长期暴露样品中的富集变得比短期暴露更明显。与这个过程一起，细菌的总丰度以及潜在的携带 ARG 的细菌在 N/MP 暴露组中也增加了，长期 N/MP 暴露导致更多的细菌属，如假单胞菌、 Syntrophomonas 和 Desulfotomaculum 与 ARG 变异密切相关。同时，观察到暴露于 50-100 nm NPs 和 200-500 nm MPs 诱导的活性氧 (ROS) 的产生增加细菌膜通透性，这可能导致更多细菌通过内部成为 ARGs 的潜在受体。 - 移动遗传元件的细菌群落转移。总体而言，目前的研究表明，渗滤液中 N/MPs 的存在促进了 ARGs 的繁殖，因为它们对细菌群落和细胞膜通透性有影响。这些发现对于理解 N/MPs 和 ARGs 联合污染的环境风险具有重要意义。

  Municipal landfill leachate is a huge reservoir of (nano)microplastics (N/MPs) and antibiotic resistance genes (ARGs). N/MPs have a proven ability to affect the growth of bacteria and composition of bacterial communities, which may further influence the spread of ARGs in the environment. To extrapolate the interactions between these two emerging contaminants, we investigated the variations of the ARG levels in leachate with exposures to different sizes of N/MPs. The results showed that ARGs were enriched in the N/MPs-exposed groups, especially in the 200–500 nm MP group. Notably, the enrichment became more pronounced in the long-term exposure samples than the short-term ones. Together with this process, the total abundance of bacteria, as well as the potential ARG-carrying bacteria, also increased in the N/MP-exposed groups, and the long-term N/MP exposure led more bacteria genera, such as Pseudomonas, Syntrophomonas, and Desulfotomaculum, to become closely associated with ARG variations. Meanwhile, the production of reactive oxygen species (ROS) induced by exposure to the 50–100 nm NPs and the 200–500 nm MPs was observed to increase bacterial membrane permeability, which might result in more bacteria becoming potential receptors of ARGs via the intra-bacterial community transfer of mobile genetic elements. Overall, the current study demonstrated that the presence of N/MPs in leachate promoted the propagation of ARGs due to their impacts on the bacterial community and cellular membrane permeability. These findings have important implications for understanding the environmental risks of the combined pollution of N/MPs and ARGs.

  https://pubs.rsc.org/fa/content/articlelanding/2020/en/d0en00511h/unauth#!divAbstract