黄霉素抑制耐药质粒接合转移的机制研究

质粒为载体的接合转移 是导致耐药基因快速传播 的重要原因，抑制耐药质粒的接合转移将有助于控制耐药基因的传播 。本课题组前期研究发现抗菌促生长剂黄霉素可显著降低携带黏菌素耐药基因（mcr-1）质粒的接合转移频率（100-1000倍），且可降低接合转移调控系统相关基因的表达，然而其对不同耐药质粒接合转移的抑制效果及其作用机制尚不清楚。基于前期结果和相关研究，我们推测黄霉素破坏细胞间接合界面体系及接合转移系统功能，从而抑制质粒在细菌间的接合转移。本课题拟以各种耐药质粒为研究对象，通过接合试验研究黄霉素对不同耐药质粒接合转移的抑制效能；并通过气相质谱、扫描电镜、实时荧光定量PCR、基因敲除及回补试验等方法研究黄霉素对接合界面的影响和接合转移系统的调节作用，揭示黄霉素抑制耐药质粒接合转移的分子机制，为扩展黄霉素用途和接合抑制剂研发提供理论基础，对减缓和控制细菌耐药性的发展具有重要的科学意义。

Plasmid-mediated conjugation plays a so important part in rapid transmission of antibiotic resistance genes (ARGs) that inhibiting the conjugative transfer of resistant plasmids will help control the prevalence of ARGs. In our previous study, we found that flavomycin, an antimicrobial growth promoter, significantly inhibited the conjugation frequency of plasmids carrying mcr-1 (100-1000 times) and the expression of genes related to conjugation transfer regulatory system. However, the inhibitory effort of flavomycin on the transfer of different resistance plasmids and its mechanism are still unclear. Based on previous results and relative reports, we hypothesized that flavomycin can damage conjugation interface and the function of conjugation system, therefore inhibiting the transfer of plasmids between bacteria. In this study, we will evaluate the effort of flavomycin on inhibiting the transfer of various plasmids carrying different resistant genes by conjugation assay. In order to reveal its inhibitor mechanism, gas chromatography-mass spectrometry, scanning electron microscope, real-time PCR, genes knockout, complementation assays and other methods will be performed to analyze the effort of flavomycin on conjugation interface and conjugation transfer system. This study will provide theoretical basis for the development of flavomycin and conjugation inhibitors, which possess vital scientific significance for mitigating and controlling the spread of bacterial resistance.