Section of Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom.
FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany.
mBio. 2019 Aug 6;10(4):e01448-19. doi: 10.1128/mBio.01448-19.
Rod-shaped bacteria have two modes of peptidoglycan synthesis: lateral synthesis and synthesis at the cell division site. These two processes are controlled by two macromolecular protein complexes, the elongasome and divisome. Recently, it has been shown that the RodA protein, which forms part of the elongasome, has peptidoglycan glycosyltransferase activity. The cell division-specific RodA homolog FtsW fulfils a similar role at the divisome. The human pathogen carries genes that encode up to six FtsW/RodA homologs; however, their functions have not yet been investigated. Analysis of deletion and depletion strains led to the identification of the essential cell division-specific FtsW protein, FtsW1. Interestingly, carries a gene that encodes a second FtsW protein, FtsW2, which can compensate for the lack of FtsW1, when expressed from an inducible promoter. also possesses three RodA homologs, RodA1, RodA2, and RodA3, and their combined absence is lethal. Cells of a double mutant are shorter and have increased antibiotic and lysozyme sensitivity, probably due to a weakened cell wall. Results from promoter activity assays revealed that expression of and is induced in the presence of antibiotics targeting penicillin binding proteins. Consistent with this, a mutant was more susceptible to the β-lactam antibiotic cefuroxime. Interestingly, overexpression of RodA3 also led to increased cefuroxime sensitivity. Our study highlights that genes encode a multitude of functional FtsW and RodA enzymes to produce its rigid cell wall and that their expression needs to be tightly regulated to maintain growth, cell division, and antibiotic resistance. The human pathogen is usually treated with high doses of β-lactam antibiotics, often combined with gentamicin. However, these antibiotics only act bacteriostatically on , and the immune system is needed to clear the infection. Therefore, individuals with a compromised immune system are at risk to develop a severe form of infection, which can be fatal in up to 30% of cases. The development of new strategies to treat infections is necessary. Here we show that the expression of some of the FtsW and RodA enzymes of is induced by the presence of β-lactam antibiotics, and the combined absence of these enzymes makes bacteria more susceptible to this class of antibiotics. The development of antimicrobial agents that inhibit the activity or production of FtsW and RodA enzymes might therefore help to improve the treatment of infections and thereby lead to a reduction in mortality.
侧向合成和在细胞分裂部位合成。这两个过程由两个大分子蛋白质复合物控制，即延长体和分裂体。最近，已经表明，形成延长体一部分的 RodA 蛋白具有肽聚糖糖基转移酶活性。细胞分裂特异性的 RodA 同源物 FtsW 在分裂体中发挥类似的作用。人类病原体 携带编码多达六个 FtsW/RodA 同源物的基因；然而，它们的功能尚未被研究。缺失和耗竭菌株的分析导致了必需的细胞分裂特异性 FtsW 蛋白 FtsW1 的鉴定。有趣的是， 携带一个编码第二个 FtsW 蛋白 FtsW2 的基因，当该基因从诱导型启动子表达时，可以弥补 FtsW1 的缺乏。 还拥有三个 RodA 同源物，RodA1、RodA2 和 RodA3，它们的共同缺失是致命的。 双突变体的细胞更短，对抗生素和溶菌酶的敏感性增加，可能是由于细胞壁减弱。启动子活性测定的结果表明，在针对青霉素结合蛋白的抗生素存在下， 和 的表达被诱导。与此一致， 突变体对β-内酰胺类抗生素头孢呋辛更敏感。有趣的是，RodA3 的过表达也导致了头孢呋辛敏感性的增加。我们的研究强调， 基因编码多种功能性 FtsW 和 RodA 酶来产生其刚性细胞壁，并且它们的表达需要严格调控以维持生长、细胞分裂和抗生素抗性。人类病原体 通常用高剂量的β-内酰胺类抗生素治疗，通常与庆大霉素联合使用。然而，这些抗生素仅对 起抑菌作用，需要免疫系统清除感染。因此，免疫系统受损的个体有患严重形式的 感染的风险，在多达 30%的病例中可能致命。有必要开发新的策略来治疗 感染。在这里，我们表明 中一些 FtsW 和 RodA 酶的表达被β-内酰胺类抗生素的存在所诱导，而这些酶的共同缺失使细菌对这类抗生素更敏感。因此，开发抑制 FtsW 和 RodA 酶活性或产生的抗菌剂可能有助于改善 感染的治疗，并由此降低死亡率。
