摘要
      环境中的抗微生物耐药性已成为一个关键问题，其通过纳米材料介导的传播正受到越来越多的关注。然而，目前的研究忽略了纳米材料的环境转化对抗生素抗性基因（ARGs）水平转移的贡献。在此，通过模拟照明或亚铁（Fe2+）转化氧化石墨烯（GO），以模拟天然发生的GO还原，并首次观察到还原的GO（rGO）对ARGs水平转移的不同影响。与原始GO相比，光还原GO显著增强了质粒载体ARGs的转移。紫外线辐射激发的稳定石墨烯自由基的显著产生引发了细菌的氧化应激，并有助于膜的渗透性。然而，当被Fe2+还原时，GO介导的ARGs转移的促进作用减弱，这归因于大rGO聚集体的物理包裹阻碍了细菌之间的质粒转移。此外，在抗生素治疗下，通过GO介导的连接产生的跨偶联菌株显示出比原始大肠杆菌更强的巨噬细胞感染。这些发现强调，纳米材料介导的ARGs转移取决于其在现实环境中的转化途径，这有助于理解抗微生物耐药性的传播。
Abstract
Antimicrobial resistance in the environment has become a critical issue and its dissemination mediated by nanomaterials is receiving increasing attention. However, current studies overlook the contribution of the environmental transformation of nanomaterials to the horizontal transfer of antibiotic resistance genes (ARGs). Herein, graphene oxide (GO) was transformed by simulated illumination or ferrous iron (Fe2+) to mimic the naturally occurring GO reduction, and for the first time, the distinct effects of reduced GO (rGO) on ARGs horizontal transfer were observed. Compared with pristine GO, the transfer of plasmid-borne ARGs was dramatically enhanced by light-reduced GO. The remarkable production of stabilized graphene radical excited by ultraviolet irradiation triggered bacterial oxidative stress and contributed to membrane permeability. However, when reduced by Fe2+, the facilitation of ARGs transfer mediated by GO was attenuated, which was attributed to the physical wrapping of large rGO aggregates that hindered plasmid transfer between bacteria. Furthermore, the generated transconjugant strain via GO-mediated conjunction showed stronger macrophage infection than the original Escherichia coli under antibiotic treatment. These findings emphasize that nanomaterial-mediated ARGs transfer depends on its transformation pathways in a realistic environment, which is helpful for the understanding of the dissemination of antimicrobial resistance.

https://www.sciencedirect.com/science/article/abs/pii/S1385894722037846