INVESTIGATING TYPE VI SECRETION IN ACINETOBACTER BAUMANNII AND ITS INTERPLAY WITH ANTIBIOTIC RESISTA

研究鲍曼不动杆菌 VI 型分泌物及其与抗生素耐药性的相互作用

• 批准号: 9156408
• 负责人: Mario Feldman
• 金额: $ 38.13万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-22 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9156408
• 关键词: Acinetobacter Infections; Acinetobacter baumannii; Affect; Amino Acids; Anti-Bacterial Agents; Antibiotic Resistance; Antibiotics; Bacteria; Biogenesis; Biological; Biological Assay; Catabolism; Cell Differentiation process; Cells; Chemotactic Factors; Communicable Diseases; Coupled; Data; Development; Eukaryota; Frequencies; Genes; Goals; Gram-Negative Bacteria; Health; Healthcare Systems; Human; Immunity; Infection; Injection of therapeutic agent; Intoxication; Investigation; Killer Cells; Knowledge; Lead; Mediating; Metabolic; Metabolic Pathway; Mission; Modeling; Modification; Multi-Drug Resistance; Multidrug-resistant Acinetobacter; Mutagenesis; Nosocomial Infections; Organism; Outcome; Pathway interactions; Peptidoglycan; Phenotype; Physiological; Physiological Adaptation; Pilum; Plants; Plasmids; Population; Process; Production; Prokaryotic Cells; Proteins; Proteomics; Recruitment Activity; Regulation; Research; Resistance; Role; Signaling Molecule; Superbug; System; Testing; Time; United States National Institutes of Health; Work; abstracting; antimicrobial; base; cell motility; clinically relevant; combat; comparative; cost; driving force; fitness; in vivo; insight; killings; novel; novel strategies; pathogen; phenylacetic acid; prevent; research study; resistant strain; transcriptome sequencing; transcriptomics; weapons

PROJECT SUMMARY/ABSTRACT Multidrug resistant (MDR) Acinetobacter baumannii has emerged as a frequent cause of nosocomial infections with some isolates resistant to all clinically relevant antibiotics. We have previously identified a type VI secretion system (T6SS) in this organism. The multi-component T6SS apparatus facilitates a dynamic contact-dependent injection of toxic effector proteins into competing bacteria. The T6SS is energetically costly, and therefore in most bacteria appears to be exquisitely regulated. We recently showed that several MDR A. baumannii isolates harbor a large, self-transmissible resistance plasmid that negatively regulates T6SS. We found that T6SS is silenced in plasmid-containing, antibiotic-resistant cells, while part of the population undergoes frequent plasmid loss and activation of the T6SS. This activation results in T6SS- mediated killing of competing bacteria but renders A. baumannii susceptible to antibiotics. We propose that differentiation of A. baumannii cells into bacterial killers involves multiple phenotypic and metabolic changes and that the fitness costs associated with the MDR and T6SS phenotypes are the driving forces for this differentiation. RNAseq and differential quantitative proteomics experiments revealed that unexpected metabolic pathways related to amino acid catabolism were plasmid-regulated. Most of these metabolic changes seem to be consequence of energetic adaptations to T6SS activation and carriage of a MDR plasmid. By mutagenesis and comparative fitness assays we will determine the importance of these metabolic changes. Interfering with these pathways may result in novel strategies to combat A. baumannii infections. We will investigate how T6SS is regulated in MDR strains that do not carry plasmids to extend our conclusions to these strains. The mechanisms by which the T6SS apparatus crosses the peptidoglycan layer of the killer cell has not been determined in any bacteria. We will define the role of a putative peptidoglycanase in this process. We have also discovered phenotypic adaptations related to plasmid loss, involving piliation and motility. The biological significance of these changes will be assessed. RNAseq data led us to the hypothesis that a metabolic intermediate, phenylacetic acid (PAA), is employed as chemoattractant to recruit prey and increase the killing efficiency. Determining the role of PAA in T6SS mediated killing may result in a new paradigm for T6SS-mediated killing with important ecological implications. The outcome of this work will be a detailed understanding of the interplay between the T6SS and the MDR phenotype and the physiological changes associated to this activation, which may lead to the development of new strategies to treat Acinetobacter infections.

项目摘要/摘要 多药耐药（MDR）鲍曼尼杆菌已成为经常出现的 一些分离株对所有临床相关抗生素具有抗性的分离株。我们有 先前在该生物体中确定了VI型分泌系统（T6SS）。多组件 T6SS设备促进了动态接触依赖性注入有毒效应蛋白 竞争细菌。 T6S在能量上的成本高昂，因此在大多数细菌中似乎 受到精心调节。我们最近表明，几个MDR A. Baumannii分离株藏有A 负调节T6SS的大型，自推断的抗性质粒。我们发现T6SS 在含质粒的抗生素耐药细胞中沉默 经常发生T6SS的质粒损失和激活。这种激活导致T6SS- 涉及竞争细菌的介导的杀死，但鲍曼尼a。A.baumannii容易受到抗生素的影响。我们 提出将鲍曼尼曲霉细胞分化为细菌杀手涉及多个 表型和代谢变化，以及与MDR相关的健身成本 T6SS表型是这种分化的驱动力。 RNASEQ和差异 定量蛋白质组学实验表明，意外的代谢途径与 氨基酸分解代谢是质粒调节的。这些代谢变化中的大多数似乎是 对T6SS激活和MDR质粒的运输的能量适应的结果。经过 诱变和比较适应性测定我们将确定这些的重要性 代谢变化。干扰这些途径可能会导致对抗A的新型策略。 Baumannii感染。我们将调查如何在不菌株的MDR菌株中调节T6SS 携带质粒以将我们的结论扩展到这些菌株。 T6SS的机制 尚未确定任何杀手室细胞肽聚糖层的设备。 细菌。我们将定义推定的肽聚糖在此过程中的作用。我们也有 发现了与质粒损失有关的表型适应，涉及仅涉及鲈鱼和运动。这 这些变化的生物学意义将得到评估。 RNASEQ数据导致我们提出了假设 代谢中间体苯乙酸（PAA）被用作趋化剂 招募猎物并提高杀戮效率。确定PAA在T6SS中介导的作用 杀戮可能会导致T6SS介导的杀戮的新范式，并具有重要的生态 含义。这项工作的结果将是对 T6SS和MDR表型以及与此激活相关的生理变化， 这可能会导致发展新策略来治疗活杆菌感染。