Mechanisms of Klebsiella pneumoniae gastrointestinal colonization

肺炎克雷伯菌胃肠道定植机制

• 批准号: 10736879
• 负责人: Muhammad Ammar Zafar
• 金额: $ 55.83万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-14 至 2028-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10736879
• 关键词: Affect; Animal Model; Antibiotic Resistance; Arginine; Biological; Biological Assay; Bypass; Catabolism; Cell membrane; Cellular Membrane; Data; Development; Diet; Disease; Ethanolamines; Failure; Feces; Gastrointestinal tract structure; Genes; Genetic Screening; Gnotobiotic; Gram-Negative Bacteria; Immune system; Immunocompetent; In Vitro; Infection; Inflammatory; Investigation; Kinetics; Klebsiella pneumoniae; Knock-out; Knowledge; Libraries; Link; Metabolic Pathway; Metabolism; Metagenomics; Modeling; Molecular; Mucous Membrane; Multi-Drug Resistance; Mus; Nosocomial Infections; Nutrient; Nutritional; Operon; Oral; Oropharyngeal; Outcome; Pathway interactions; Patients; Prevention; Process; Regulation; Role; Route; Site; Source; System; burden of illness; colonization resistance; combat; diarrheal disease; digital; drug resistant pathogen; enteric pathogen; epidemiology study; fitness; gastrointestinal; gene product; genomic locus; gut colonization; gut microbiome; gut microbiota; host colonization; in vivo; insight; member; metabolomics; metagenome; metagenomic sequencing; microbiome; microbiome components; microbiota; microorganism; mouse model; mutant; novel; pathogen; pathogenic bacteria; public health relevance; success; transmission process; uptake

Abstract Hospital-acquired infections (HAI) resulting from the transmission of drug-resistant pathogens affect hundreds of millions of patients worldwide. Klebsiella pneumoniae (Kpn), a gram-negative bacterium, is notorious for causing HAI, with many of these infections difficult to treat as Kpn has become multi-drug resistant. Epidemiological studies suggest that gastrointestinal (GI) colonization of Kpn is a major reservoir through which Kpn can cause disease manifestations either in the colonized host or transmit from host to host. This site of Kpn colonization has not been the focus of previous studies as a tractable model of Kpn GI colonization, and host-to-host transmission did not exist. We have recently developed a murine model that allows for the study of Kpn mucosal (oropharynx and GI) colonization, shedding within feces, and transmission through the fecal-oral route. Using an oral route of inoculation and fecal shedding as a marker for GI colonization, we show that Kpn can asymptomatically colonize the GI tract of immunocompetent mice and modifies the host GI microbiota. We premise that specific Kpn genes contribute to its GI colonization, and the products of these genes could serve as novel targets for the prevention of the establishment of GI colonization. More recently, we used our murine model to screen a library of Kpn random transposon mutants (In-seq) to identify the complete set of “GI colonization” genes from a single isolate. A metagenomics sequencing analysis further identified bacterial species and the metabolic pathways affected by Kpn in the GI tract. Herein, we will focus on two sets of pathways identified through In-seq whose products allow Kpn to overcome colonization resistance provided by the resident gut microbiota. Thus, in Aim#1, we will focus on the ethanolamine utilization pathway genes (eut) of Kpn that allow it to utilize ethanolamine (EA), a byproduct of cellular membranes and diet in the gut that can serve as an alternative nutrient source. Unlike many other enteric pathogens that contain a single eut operon, Kpn has two genetically distinct eut operons. We will identify the role of each eut locus in EA metabolism and determine the underlying molecular mechanism through which EA metabolism provides Kpn with a fitness advantage against members of the microbiome. Aim#2 will take a different approach by focusing on the contact-dependent killing machinery of the Kpn (Type 6 secretion system [T6SS]) in overcoming colonization resistance provided by the resident microbiota. We will focus on the unique regulatory mechanism that modulates the expression of Kpn T6SS in the GI tract and provide it with a selective and competitive advantage against the resident gut microbiota. Results from these studies would provide us with a fundamental understanding of the molecular mechanisms involved in the establishment of GI colonization by an incoming pathogen. These studies will also lay the groundwork for developing potential strategies to reduce the Kpn disease burden.

抽象的 由耐药病原体传播引起的医院获得感染（HAI）影响了数百种 全球数百万患者。革兰氏阴性细菌Klebsiella肺炎（KPN）臭名昭著 引起HAI，其中许多感染很难将KPN视为抗多药。 流行病学研究表明，KPN的胃肠道（GI）定植是通过 KPN可以在殖民的宿主中引起疾病​​表现，或者从宿主传播到宿主。这个网站 KPN殖民化并不是先前研究的重点，作为KPN GI定植的可探讨模型，并且 主机到宿主传输不存在。我们最近开发了一种鼠模型，该模型允许研究 KPN粘膜（口咽和GI）定植，粪便中脱落，并通过粪便传播 路线。我们使用口服接种和粪便脱落作为胃肠道定植的标记 KPN可以不对称地定居于免疫能力小鼠的胃肠道，并修改宿主GI 微生物群。我们前提是特定的KPN基因有助于其GI定植，这些基因的产物 可以作为预防胃肠道殖民建立的新目标。最近，我们使用了 我们的鼠模型以筛选KPN随机转座子突变体（In-Seq）的库，以识别完整的集合 来自单个分离物的“ GI殖民化”基因。宏基因组测序分析进一步鉴定了细菌 胃肠道中KPN影响的物种和代谢途径。在此，我们将重点关注两组途径 通过seq确定其产品允许KPN克服居民提供的定殖抗性 肠道菌群。在AIM＃1中，我们将专注于KPN的乙醇胺利用率途径基因（EUT） 允许它利用乙醇胺（EA），乙醇胺和肠道中的细胞膜和饮食的副产品可以用作 替代营养来源。与许多包含单个EUT操纵子的其他促进病原体不同，KPN有两个 遗传上不同的EUT操纵子。我们将确定每个EUT基因座在EA代谢中的作用，并确定 EA代谢提供了具有适应性优势的KPN的基本分子机制 微生物组的成员。 AIM＃2将通过关注接触依赖性杀戮来采取不同的方法 KPN的机械（6型分泌系统[T6SS]）克服了由 居民微生物群。我们将专注于调节表达的独特调节机制 胃肠道中的KPN T6SS的数量，并为居民提供选择性和竞争优势 微生物群。这些研究的结果将为我们提供对分子的基本理解 通过传入的病原体建立胃肠道定植的机制。这些研究也将 为制定减少KPN疾病伯恩的潜在策略的基础。