Rifampicin exerts anti-mucoviscous activity against hypervirulent Klebsiella pneumoniae via binding to the RNA polymerase β subunit
Rifampicin exerts anti-mucoviscous activity against hypervirulent Klebsiella pneumoniae via binding to the RNA polymerase β subunit
复制标题
利福平通过与 RNA 聚合酶 β 亚基结合，对高毒力肺炎克雷伯菌发挥抗粘膜粘稠活性
DOI：
10.1016/j.jgar.2022.11.018
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发表时间：
2023
影响因子：
4.6
通讯作者：
Kawaguchi Tomoya
中科院分区：
文献类型：
--
作者：
Tohda Mitsunori;Oinuma Ken-Ichi;Sakiyama Arata;Tsubouchi Taishi;Niki Mamiko;Namikawa Hiroki;Yamane Kenshi;Yamada Koichi;Watanabe Tetsuya;Asai Kazuhisa;Kakeya Hiroshi;Kaneko Yukihiro;Kawaguchi Tomoya
目的在高致病性肺炎克雷伯菌（hvKP）中，高粘性荚膜是主要的毒力决定因素。我们以前发现，利福平（RFP），一种结合并抑制RNA聚合酶β亚基（RpoB）的杀菌药物，通过抑制rmpA（一种胶囊产生的调节剂）来增强抗hvKP的抗粘膜粘性活性。在这里，我们的目的是确定RFP是否通过其结合RpoB.MethodsFive自发RFP耐药突变体（R1-R5）的亚生长抑制浓度发挥这种作用从hvKP临床分离，并进行全基因组测序和粘膜粘度分析。随后，使用两步等位基因交换程序来创建arpoB突变体R6和具有野生型poB的回复突变体R1-R5（命名为R1′-R5′）。结果R1-R5均存在rpo基因的非同义点突变，且对RFP的杀菌和抗粘膜粘性活性具有高度抗性。R6的性质与R1-R5相似，R1′-R5′对RFP的反应与野生型相同，rmpA和magA转录水平和囊膜厚度与粘膜粘度水平相关。这如何导致rmpA抑制的机制仍有待探索。
ObjectivesIn hypervirulentKlebsiella pneumoniae(hvKP), the hypermucoviscous capsule is known to be a major virulence determinant. We previously discovered that rifampicin (RFP), a bactericidal drug that binds to and inhibits the β subunit of RNA polymerase (RpoB), elicits anti-mucoviscous activity against hvKP by suppressingrmpA, a regulator of capsule production. Here, we aimed to determine whether RFP exerts this effect at sub-growth-inhibitory concentrations via its binding to RpoB.MethodsFive spontaneous RFP-resistant mutants (R1–R5) were prepared from an hvKP clinical isolate and subjected to whole genome sequencing and mucoviscosity analyses. Subsequently, a two-step allelic exchange procedure was used to create arpoBmutant R6 and revertants with wild-typerpoBfrom R1–R5 (named R1′–R5′). Transcription levels ofrmpAand the capsular polysaccharide polymerase genemagAand capsule thickness of R1–R5 and R1′–R5′ grown without or with RFP were evaluated by quantitative reverse transcription polymerase chain reaction and microscopic observation using India ink staining.ResultsR1–R5 all had non-synonymous point mutations inrpoBand were highly resistant to the bactericidal effects and anti-mucoviscous activity of RFP. While the properties of R6 were similar to those of R1–R5, the responses of R1′–R5′ to RFP were identical to those of the wild type.rmpAandmagAtranscription levels and capsule thickness correlated well with the mucoviscosity levels.ConclusionsRFP exerts anti-mucoviscous activity by binding to RpoB. The mechanism of how this causesrmpAsuppression remains to be explored.