State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, 300071, China.
School of Medicine, Southern University of Science and Technology (SUSTec), Shenzhen 518055, China.
ACS Infect Dis. 2021 Mar 12;7(3):636-649. doi: 10.1021/acsinfecdis.0c00837. Epub 2021 Mar 2.
In the niches that and coinhabit, the later pathogen produces phenazine antibiotics to inhibit the growth of . Recently, a group of halogenated phenazines (HPs) has been shown to have potent antimicrobial activities against ; however, no HP-resistant mutant has been reported. Here, we demonstrate that develops HP-resistance via single amino acid change (Arg116Cys) in a transcriptional repressor TetR21. RNA-seq analysis showed that the TetR21 variation caused drastic up-regulation of an adjacent gene (halogenated phenazine resistance protein of ). Deletion of the in the TetR21 background restored bacterial susceptibility to HP, while overexpression in conferred HP-resistance. The expression of HprS is under tight transcriptional control of the TetR21 via direct binding to the promoter region of . The R116C mutation in TetR21 significantly reduced its DNA binding affinity. Moreover, natural phenazine antibiotics (phenazine-1-carboxylic acid and pyocyanin) and a HP analog (HP-22) are ligands for the TetR21, regulating its repressor activity. Combining homology analysis and LC-MS/MS assay we demonstrated that HprS is a phenazine efflux pump. To the best of our knowledge, we provide the first report of phenazine efflux pump in . Interestingly, the TetR21 variation has been found in some clinical isolates, and a laboratory strain of with TetR21 variation showed enhanced growth competitiveness toward and promoted coinfection with in the host environment, demonstrating significance of the mutation in host infections.
在 和 共同占据的生态位中，后来的病原体产生吩嗪抗生素来抑制 的生长。最近，一组卤代吩嗪（HPs）已被证明对 具有很强的抗菌活性；然而，尚未报道 HP 抗性突变体。在这里，我们证明 通过转录抑制剂 TetR21 中的单个氨基酸变化（Arg116Cys）来发展 HP 抗性。RNA-seq 分析表明，TetR21 变异导致相邻基因 的强烈上调（卤代吩嗪抗性蛋白）。在 TetR21 背景下删除 恢复了细菌对 HP 的敏感性，而 在 中过表达赋予了 HP 抗性。HprS 的表达受 TetR21 的紧密转录控制，通过直接结合 启动子区域。TetR21 中的 R116C 突变显着降低了其 DNA 结合亲和力。此外，天然吩嗪抗生素（吩嗪-1-羧酸和绿脓菌素）和 HP 类似物（HP-22）是 TetR21 的配体，调节其抑制剂活性。通过同源性分析和 LC-MS/MS 测定，我们证明 HprS 是一种吩嗪外排泵。据我们所知，我们首次报道了 在 中的吩嗪外排泵。有趣的是，已经在一些临床 分离株中发现了 TetR21 变异，并且具有 TetR21 变异的 实验室菌株在宿主环境中显示出对 的生长竞争力增强，并促进与 的共感染，表明该突变在宿主感染中的重要性。
