2020年01月29日

    近日，团队李桂英教授和硕士生陈晓芳等人在细菌耐药基因转移方面取得最新研究进展，研究成果以《Natural sphalerite nanoparticles can accelerate horizontal transfer of plasmid-mediated antibiotic-resistance genes》为题发表在Environment International, 2020, 136: 105497上。该工作首次揭示了环境自然因素-天然矿物对细菌耐药基因接合转移的加速作用，并从细菌应激的角度详细阐明了矿物介导耐药基因转移的可能的相关机制。

    该论文采用天然闪锌矿（NS）纳米颗粒作为天然矿物的代表，研究了其对细菌耐药基因的接合转移的影响。结果表明NS的暴露可以导致细菌细胞产生大量的ROSs，进而激发细菌的氧化应激和抗氧化系统的反应。在矿物作用下，细菌的氧化抗氧化系统指标均明显升高，并造成细菌细胞膜状态的改变。NS的复杂组分和纳米级ZnS的结构能够直接影响供体菌和受体菌的细胞膜的融合和DNA的跨膜转运。此外，NS可提高供体菌和受体菌内应激基因表达。在矿物刺激供体菌和受体菌之间发生接合转移过程时，其细菌内部基因表达的上调是细菌活性变化以及细菌防御机制的积极应对的主要表现。细菌体内应激基因表达水平的升高，也表明矿物对供体细菌和受体细菌接合转移效率的促进作用。研究结果为了解天然矿物导致的细菌耐药性风险提供了新的理解机制。

    论文摘要

    ABSTRACT：Minerals and microorganisms are integral parts of natural environments, and they inevitably interact. Antibiotic-resistance genes (ARGs) significantly threaten modern healthcare. However, the effects of natural minerals on ARG propagation in aquatic systems are not fully understood. The present work studied the effects of natural sphalerite (NS) nanoparticles on the horizontal transfer of ARGs from Escherichia coli DH5α (CTX) (donor) to E. coli C600 (Sm) (recipient), and from E. coli DH5α (MCR) (donor) to E. coli C600 (Sm), and their underlying mechanisms. NS particles (0.5–50 mg L−1) induced an NS-concentration-dependent increase in conjugative transfer frequency. The underlying mechanisms associated with the facilitated ARG transfer included the production of intracellular reactive oxygen species, the SOS response, changes in bacterial cell morphology, and alteration of mRNA levels of bacterial cell membrane protein-related genes and genes associated with conjugative ARG transfer. The information herein offers new mechanistic understanding of risks of bacterial resistance resulting from NS.

    论文链接：https://www.sciencedirect.com/science/article/pii/S0160412019345039