Characterizing the role of antimicrobial peptide resistance in plague transmission

表征抗菌肽耐药性在鼠疫传播中的作用

• 批准号: 9398839
• 负责人: Mark A Fisher
• 金额: $ 37.88万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-12 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9398839
• 关键词: Address; Anabolism; Antibiotics; Antimicrobial Cationic Peptides; Antimicrobial Resistance; Attenuated; Bacteria; Bacterial Infections; Binding; Biological Assay; Biology; Bioterrorism; Cell Membrane Permeability; Communities; Complex; Data; Fleas; Fluorescence Microscopy; Genes; Genetic; Genome; Goals; Health; Human; Hypersensitivity; In Vitro; Infection; Investigation; Knowledge; Label; Lead; Libraries; Lipid A; Lipopolysaccharides; Mass Spectrum Analysis; Mediating; Membrane; Methods; Modification; Molecular; Multi-Drug Resistance; Mutation; Nature; PAWR protein; Pathogenesis; Phenotype; Plague; Plasmids; Play; Polymyxin Resistance; Polymyxins; Predisposition; Public Health; Publishing; Recording of previous events; Research; Resistance; Role; Southwestern United States; Testing; Virulent; Yersinia pestis; antimicrobial; antimicrobial peptide; bacterial resistance; biophysical techniques; colistin resistance; enterobacterial common antigen; gene function; genetic approach; improved; insight; killings; mutant; new therapeutic target; novel; pathogen; periplasm; resistance gene; resistance mechanism; response; screening; transmission process; vector; weapons

PROJECT SUMMARY It is difficult to overstate the impact Yersinia pestis, the bacterial agent of plague, has had on human history. It is of great concern as a potential agent of bioterrorism because of its highly virulent nature, and it consistently infects thousands of people per year in endemic foci around the world, including the southwestern United States. Despite these facts, there is much that is unknown about the ability of Y. pestis to infect both flea vectors and mammalian hosts, and its ability to undergo successful transmission between them. The goal of this project is to determine the genetic and molecular mechanisms of resistance to cationic antimicrobial peptides (CAMPs) in Y. pestis, and the role this resistance plays in allowing it to successfully infect fleas. Data from our lab revealed that numerous Y. pestis transposon mutants that were unable to maintain successful flea infections also showed in vitro hypersensitivity to CAMPs. Two mutants contained insertions in genes predicted to block modification of the outer membrane lipopolysaccharide, and we recently published data that this was in fact the cause of the mutants' CAMP sensitivity. Several mutations however were in novel or hypothetical genes not previously known to be involved in CAMP resistance. Additionally, disruption of genes involved in biosynthesis of the enterobacterial common antigen resulted in unexpected CAMP-susceptibility in Y. pestis by an unknown mechanism. These data, along with the recent discovery of the plasmid-mediated mcr colistin resistance genes, indicate that CAMP resistance is more complex, and less well understood, than previously thought. The first specific aim of this project is to investigate structural and genetic changes present in these CAMP- susceptible mutants to improve our understanding of the mechanisms of CAMP resistance. Since CAMPs, such as polymyxins, are often one of the only classes of antibiotics with activity against multi-drug resistant bacterial infections, identifying novel mechanisms of resistance is of critical importance. The second specific aim involves constructing a comprehensive, ordered transposon mutant library of all non-essential genes in Y. pestis KIM6+. This library will be screened for mutants that are susceptible to structurally diverse CAMPs in order to identify additional and potentially novel mechanisms of resistance. Mutants identified in this screen will be analyzed using the biophysical and genetic approaches from the first aim to elucidate their mechanisms of CAMP resistance. The third specific aim is to determine the potential role of different mechanisms of CAMP resistance in transmission by testing the ability of the mutants to maintain infection, and by determining the distribution of mutants in a natural flea vector. The knowledge obtained from this project on CAMP resistance mechanisms will open up a number of new trajectories in plague and antimicrobial resistance research, and the ordered mutant library could stimulate additional investigation into the biology of this important human pathogen. Improving our understanding of CAMP resistance is crucial given the status of polymyxins as WHO “Critically Important Antimicrobials,” and the recent discovery of transmissible (mcr-1) resistance. Loss of this class of antibiotics could herald the era of untreatable infections. !

项目摘要 鼠疫耶尔森氏菌（Yersinia pestis）是鼠疫的病原体，它对人类历史的影响怎么强调都不过分。具有 作为生物恐怖主义的潜在代理人，由于其高度致命的性质，它一直感染 每年有数千人在世界各地的地方性疫源地，包括美国西南部。尽管 尽管有这些事实，但关于Y的能力还有很多未知之处。鼠疫菌感染跳蚤媒介和哺乳动物 它是一种能够在宿主之间成功传播的病毒。该项目的目标是确定 探讨了Y.鼠疫，以及 这种抵抗力使它能够成功地感染跳蚤。我们实验室的数据显示，许多Y。鼠疫 不能维持成功跳蚤感染的转座子突变体也表现出对 营两个突变体包含插入的基因预测阻止修改的外膜 我们最近发表的数据表明，这实际上是突变体对CAMP敏感的原因。 然而，有几个突变发生在新的或假设的基因中，这些基因以前并不知道与CAMP有关 阻力此外，参与肠细菌共同抗原生物合成的基因的破坏导致 在Y.一种未知机制的瘟疫这些数据，沿着最近的 质粒介导的mcr粘菌素耐药基因的发现，表明CAMP耐药更为复杂， 也不像以前想象的那么容易理解 该项目的第一个具体目标是研究这些CAMP中存在的结构和遗传变化， 敏感突变体，以提高我们对CAMP抗性机制的理解。由于营地，如 多粘菌素通常是仅有的一类具有抗多药耐药细菌活性的抗生素 感染，确定新的耐药机制至关重要。第二个具体目标涉及 构建一个完整的、有序的Y.鼠疫KIM 6+。这 文库将筛选对结构多样的CAMPs敏感的突变体，以鉴定另外的 和潜在的新的耐药机制。在该筛选中鉴定的突变体将使用 生物物理和遗传方法从第一个目的是阐明其CAMP抗性的机制。第三 具体目标是通过测试确定CAMP抗性的不同机制在传播中的潜在作用 突变体维持感染的能力，并通过确定突变体在自然跳蚤中的分布 vector.从这个项目中获得的关于CAMP抗性机制的知识将开辟许多新的研究领域。 鼠疫和抗菌素耐药性研究的轨迹，有序突变库可以刺激更多的 对这种重要的人类病原体的生物学研究。提高我们对CAMP抗性的认识 鉴于多粘菌素作为WHO“极其重要的抗菌剂”的地位，以及最近发现的 可传递（mcr-1）抗性。失去这类抗生素可能预示着无法治疗的感染时代的到来。 !