Characterization of a Novel E. coli Type III Secretion System Associated with Increased Patient Mortality

与患者死亡率增加相关的新型大肠杆菌 III 型分泌系统的表征

基本信息

批准号：
10506437
负责人：
Joshua T Thaden
金额：
$ 18.71万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-01 至 2027-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10506437
关键词：
Address Adhesions Affect Anti-Bacterial Agents Antibiotic Resistance Antibiotics Area Award Bacteremia Bacteria Bacterial Adhesins Bacterial Infections Basic Science Binding Bioinformatics Biological Assay Biological Markers Cell Communication Cell Death Cells Charge Classical Complement Pathway Clinical Clinical Treatment Complement Complement 1q Complement Activation Data Development Development Plans Diagnostic Drug Targeting E. coli bacteremia Enrollment Escherichia coli Escherichia coli Infections Escherichia coli Proteins Event Fostering Funding Genes Genetic Genetic Variation Genotype Goals Gram-Negative Bacterial Infections Homologous Gene Human Immune response Impairment Infection Island Knowledge Laboratories Literature Mass Spectrum Analysis Measures Mediating Mentors Mission Modeling Modernization Mouse Strains Mus Organ Organism Outcome Pathogenesis Pathogenicity Island Patient-Focused Outcomes Patients Performance Phagocytes Phagosomes Phenotype Prognostic Marker Proteins Pseudomonas aeruginosa Public Health Research Resistance Role Scientist Seminal Sepsis Serum Side Structure Surface Syringes System Testing Therapeutic Tissues Treatment Factor Type III Secretion System Pathway United States National Institutes of Health Validation Variant Virulence Work bacterial genetics base career development cohort genetic approach genome sequencing high risk improved insight microbial mortality mortality risk novel novel therapeutics pathogen prognostic model prognostic performance prognostic value scaffold skills targeted treatment translocase

项目摘要

ABSTRACT Clinical outcomes in invasive gram-negative bacterial infections are determined by the interplay of patient, treatment, and bacterial variables. Significant progress has been made in understanding patient and treatment factors; however, little is known about how bacterial genetic variation influences patient outcomes. This is an important gap in understanding microbial pathogenesis and limits the ability to identify drug targets critical in human pathogenesis. To address this problem, the long-term goal is to interrogate bacterial pathogenesis in humans by defining the impact of bacterial genetic variation on the outcome of patients with gram-negative bacteremia. This knowledge can be leveraged to identify novel treatments. The career development plan reflects this long-term goal as the emphasis is to develop quantitative and lab expertise to independently identify and explore associations between bacterial genetics and patient outcomes. The objective in this proposal is to characterize two putative pathogenicity islands (PPI), variably present in E. coli, that are promising for their roles in pathogenesis and potential as drug targets. The two PPI were identified by the applicant and encode genes homologous to a type III secretion system (T3SS) structural apparatus (PPI-1) and translocases/adhesin (PPI-2). PPI-1/PPI-2 are not present in typical laboratory strains of E. coli and so have not been significantly studied. Presence of PPI-1/PPI-2 associated with increased mortality in patients with E. coli bacteremia, and deletions in PPI-1/PPI-2 allowed for complement-mediated killing of E. coli in serum and impaired E. coli-host cell interactions (decreased invasion). Further, PPI-1/PPI-2 functioned as a prognostic biomarker that improved ability to identify patients at high risk of mortality. The central hypothesis is that PPI-1 and PPI-2 function together as a T3SS that mediates complement-mediated serum resistance and tissue invasiveness to influence patient outcomes, and presence of PPI-1/PPI-2 provides prognostic value in patients with E. coli BSI. This will be tested through two specific aims (SA): 1) Determine how PPI-1 and PPI-2 affect virulence to influence patient outcome, and 2) Define value of PPI-1 and PPI-2 genotype as prognostic biomarkers for E. coli bacteremia. SA1 will identify how PPI-1/PPI-2 mediates resistance to complement activation, verify that PPI-1/PPI-2 is a functional T3SS, and determine the relative contributions of serum killing versus T3SS function to virulence. SA2 will use an existing external validation cohort to show that incorporating bacterial genetics with clinical variables improves prognostic models of clinical outcomes in E. coli bacteremia. Characterization of PPI-1/PPI-2 will increase our understanding of E. coli pathogenesis and pave the way for novel therapeutics. For example, a protein in PPI-2 is homologous to a drug target that the applicant and others previously exploited in Pseudomonas aeruginosa. The skills and mentoring acquired during this award will scaffold development into an independent clinician-scientist focused on the critical area of gram-negative infections.

抽象的侵袭性革兰氏阴性细菌感染的临床结果取决于患者之间的相互作用，治疗和细菌变量。在了解患者和治疗方面取得了重大进展因素；然而，人们对细菌遗传变异如何影响患者结果知之甚少。这是一个在理解微生物发病机制方面存在重大差距，并限制了识别关键药物靶标的能力人体发病机制。为了解决这个问题，长期目标是探究细菌的发病机制。通过定义细菌遗传变异对革兰氏阴性患者结果的影响来对人类进行研究菌血症。这些知识可用于确定新的治疗方法。职业发展计划反映了这一长期目标，因为重点是发展定量和实验室专业知识，以独立识别并探索细菌遗传学与患者结果之间的关联。本次活动的目的是该提案的目的是描述大肠杆菌中不同程度存在的两个假定致病岛（PPI）的特征，它们是它们在发病机制中的作用和作为药物靶点的潜力很有前景。这两个 PPI 是由申请人并编码与III型分泌系统（T3SS）结构装置（PPI-1）同源的基因和易位酶/粘附素 (PPI-2)。 PPI-1/PPI-2 不存在于大肠杆菌等典型实验室菌株中尚未得到显着研究。 PPI-1/PPI-2 的存在与患者死亡率增加相关大肠杆菌菌血症，PPI-1/PPI-2 的缺失允许补体介导的大肠杆菌杀死血清和大肠杆菌-宿主细胞相互作用受损（侵袭减少）。此外，PPI-1/PPI-2 还充当预后生物标志物，提高识别高死亡风险患者的能力。中心假设是 PPI-1 和 PPI-2 一起作为 T3SS 发挥作用，介导补体介导的血清抵抗，并且组织侵袭性影响患者的结果，PPI-1/PPI-2 的存在提供了预后价值大肠杆菌 BSI 患者。这将通过两个具体目标 (SA) 进行测试：1) 确定 PPI-1 和 PPI-2 如何影响毒力从而影响患者结果，以及 2) 定义 PPI-1 和 PPI-2 基因型的预后价值大肠杆菌菌血症的生物标志物。 SA1 将识别 PPI-1/PPI-2 如何介导补体抵抗激活，验证 PPI-1/PPI-2 是功能性 T3SS，并确定血清杀伤的相对贡献与 T3SS 的毒力功能相比。 SA2 将使用现有的外部验证队列来表明，合并具有临床变量的细菌遗传学改善了大肠杆菌菌血症临床结果的预后模型。 PPI-1/PPI-2 的表征将增加我们对大肠杆菌发病机制的了解，并为进一步研究铺平道路。新疗法。例如，PPI-2中的一种蛋白质与申请人和其研究的药物靶标同源。其他先前在铜绿假单胞菌中利用的。在此奖项期间获得的技能和指导将发展成为专注于革兰氏阴性菌关键领域的独立临床医生科学家感染。