Elucidating the mechanisms of transient polymyxin resistance in pathogenic E. coli.

阐明致病性大肠杆菌瞬时多粘菌素耐药机制。

• 批准号: 10224796
• 负责人: Melanie N Hurst
• 金额: $ 2.49万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2022-05-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10224796
• 关键词: Anogenital region; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Attention; Bacteria; Bacterial Chromosomes; Base Sequence; Cations; Cells; Code; Cues; Data; Disease; Elements; Ensure; Enterobacteriaceae; Environment; Enzymes; Escherichia coli; Event; Exhibits; Frequencies; Genes; Genetic; Genetic Transcription; Genome; Genomics; Goals; Heterogeneity; Immune; In Vitro; Individual; Infection; Iron; Lead; Lipid A; Membrane; Minimum Inhibitory Concentration measurement; Modification; Molecular Biology; OmpR protein; Operating System; Output; Pathogenicity; Phosphotransferases; Phylogenetic Analysis; Polymyxin B; Polymyxin B resistance; Polymyxin Resistance; Population; Probiotics; Property; Receptor Signaling; Recurrence; Regulation; Regulon; Reporter; Reporting; Research; Resistance; Resort; Role; Salmonella; Signal Transduction; Signal Transduction Pathway; Specificity; Stress; System; Testing; Transcriptional Activation; Untranslated RNA; Up-Regulation; Urethra; Urinary tract; Urinary tract infection; Uropathogenic E. coli; Virulence; Work; antimicrobial; bacterial fitness; bacterial resistance; colistin resistance; extracellular; fitness; flexibility; genetic element; genome-wide analysis; global health; gut colonization; insight; interdisciplinary approach; member; microbial; mouse model; pathogenic Escherichia coli; pathogenic bacteria; polypeptide; prevent; programs; protein-histidine kinase; resistance mechanism; response; sensor; sensor histidine kinase

Defining Differences in how LPS modification is Regulated in Different E. coli pathotypes Project Summary Cells encounter a constant barrage of extracellular cues to which they respond using only the finite number of signal transduction pathways encoded within their genome. While we understand how individual signal transduction systems operate, little is known about how distinct signaling systems interact to integrate information and/or expand their signal responses. The overall goal of this project is to understand how signaling flexibility benefits the responses of different E. coli strains to cationic polypeptides. Although much attention is placed on the acquisition of antibiotic resistance markers by the Enterobacteriaceae, there is increasing evidence that bacteria can also mount transient resistance to antibiotics via the upregulation of chromosomally encoded markers. For example, the pmrC gene encoded by Salmonella spp and E. coli species is an orthologue of the mcr-1 gene that imparts resistance to colistin antibiotics. We have recently demonstrated that transient resistance to polymyxin B arises in strains of uropathogenic E. coli, following stimulation with ferric iron. We subsequently found that the transient polymyxin B resistance is brought about via the activation of the PmrB sensor kinase, a member of the PmrAB two-component system (TCS). Bacterial TCSs comprise a membrane- embedded histidine kinase that is the signal receptor, and a response regulator protein that directs the corresponding cellular changes. Although there are sequence-based determinants that dictate specificity among cognate TCS partners, we discovered strong interactions between the PmrAB and QseBC TCSs, in which the PmrB histidine kinase readily activates both its cognate partner PmrA and the non-cognate response regulator QseB in response to ferric iron, leading to a 16-fold increase in the MIC. I hypothesize that coordinated regulation of PmrA and QseB leads to upregulation of genes critical for lipid A modification that in turn protects bacteria from the insults of polymyxin B and other cationic polypeptides. I will test this hypothesis in three aims, in which I will: (1) Define the PmrA and QseB regulons in response to polymyxin B and define the mechanism by which PmrA and QseB activation leads to polymyxin B resistance. (2) Determine how the QseBC and PmrAB interactions have evolved to benefit bacterial fitness in different niches, and; (3) Ascertain how the amount of conservation present in the QseBC-PmrAB signaling cascade in E. coli strains from different phylogenetic clades and with different pathogenic strategies. Towards these goals, an inter-disciplinary approach will be followed, encompassing molecular biology, genome-wide analyses of transcription and robust murine models of infection. Combined these studies will provide mechanistic details into a mechanism that allows bacteria to survive one of the last resort antibiotics and will provide insights into the conservation of the QseBC- PmrAB circuitry in different E. coli pathotypes.

定义在不同的大肠杆菌病原体中调节LPS修饰的差异 项目摘要 细胞遇到恒定的细胞外提示，它们仅使用有限数量的响应 信号转导途径在其基因组中编码。虽然我们了解个人信号 转导系统运行，对不同的信号系统如何相互作用以集成几乎一无所知 信息和/或扩展其信号响应。该项目的总体目标是了解信号 灵活性使不同大肠杆菌菌株对阳离子多肽的反应有益。虽然很多关注是 在肠杆菌科取得抗生素耐药性标记上，有越来越多的证据 该细菌还可以通过染色体编码的上调来实现对抗生素的短暂耐药性 标记。例如，由沙门氏菌和大肠杆菌物种编码的PMRC基因是直系同源物 MCR-1基因赋予抗co菌素抗生素的抗性。我们最近证明了瞬态 在用铁铁刺激后，对多粘蛋白B的耐药性在肝病大肠杆菌菌株中产生。我们 随后发现，瞬时多粘蛋白B电阻是通过PMRB的激活引起的 传感器激酶，PMRAB两组分系统（TCS）的成员。细菌TCSS包括膜 嵌入的组氨酸激酶是信号受体，以及一种导向的响应调节蛋白 相应的细胞变化。尽管有基于序列的决定因素决定了特殊性 同源性TCS合作伙伴，我们发现了PMRAB和QSEBC TCSS之间的强烈互动，其中 PMRB组氨酸激酶很容易激活其认知伴侣PMRA和非认知响应调节剂 QSEB响应铁铁，导致MIC增加了16倍。我假设该协调的法规 PMRA和QSEB导致对脂质至关重要的基因的上调，而修饰又保护细菌 来自多粘蛋白B和其他阳离子多肽的侮辱。我将以三个目的检验这一假设，其中 我将：（1）针对多粘肽B定义PMRA和QSEB调节子，并定义了该机制 PMRA和QSEB激活会导致多粘蛋白B耐药性。 （2）确定QSEBC和PMRAB的方式 相互作用已演变为有益于不同壁ni的细菌适应性，并且； （3）确定如何 来自不同系统发育进化枝的大肠杆菌菌株中的QSEBC-PMRAB信号级联 并具有不同的致病策略。为了实现这些目标，将遵循跨学科的方法， 包括分子生物学，全基因组的转录分析和稳健的鼠类感染模型。 这些研究的结合将提供机械细节，以使细菌能够在一种机制中生存。 最后的度假抗生素，并将提供有关QSEBC-PMRAB电路保存的见解 大肠杆菌病原体。