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：
10643910
负责人：
Joshua T Thaden
金额：
$ 18.33万
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/10643910
关键词：
Address Adhesions Affect Anti-Bacterial Agents Antibiotic Resistance Antibiotics Area Award Bacteremia Bacteria Bacterial Adhesins Basic Science Binding Bioinformatics Biological Assay Biological Markers Cell Communication Cell Death Cells Charge Classical Complement Pathway Clinical 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 Invaded 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 Protein Secretion 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 career development cohort complement deficiency 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.

抽象的侵入性革兰氏阴性细菌感染的临床结局由患者的相互作用确定处理和细菌变量。在理解患者和治疗方面取得了重大进展因素；然而，关于细菌遗传变异如何影响患者结局的知之甚少。这是一个理解微生物发病机理的重要差距，并限制了鉴定药物靶标至关重要的能力人类发病机理。为了解决这个问题，长期目标是询问细菌发病机理人类通过定义细菌遗传变异对革兰氏阴性患者结局的影响菌血症。可以利用这些知识来识别新的治疗方法。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局之间的关联。目的建议是表征两个假定的致病岛（PPI），大肠杆菌中存在可变他们在发病机理中的作用和作为药物靶标的潜力有希望。这两个PPI通过申请人和编码与III型分泌系统（T3SS）结构设备（PPI-1）同源的基因和易位酶/粘附素（PPI-2）。 PPI-1/PPI-2不存在于大肠杆菌的典型实验室菌株中，因此尚未得到显着研究。 PPI-1/PPI-2的存在与患者死亡率增加有关大肠杆菌菌血症以及PPI-1/PPI 2中的缺失允许补体介导的大肠杆菌在血清和大肠杆菌宿主细胞相互作用受损（侵袭降低）。此外，PPI-1/PPI-2充当预后的生物标志物可以提高鉴定患者高死亡风险的患者的能力。中心假设是 PPI-1和PPI-2一起起着介导补体介导的血清耐药性和组织侵入性影响患者的结局，并且PPI-1/PPI-2的存在提供了预后价值大肠杆菌BSI的患者。这将通过两个特定目标（SA）进行测试：1）确定PPI-1和PPI-2的方式影响毒力影响患者的结果，2）将PPI-1和PPI-2基因型的价值定义为预后大肠杆菌菌血症的生物标志物。 SA1将确定PPI-1/PPI-2如何介导抵抗力的补充性激活，验证PPI-1/PPI-2是功能性T3SS，并确定血清杀死的相对贡献与T3SS的功能相对于毒力。 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中临床结局的预后模型。 PPI-1/PPI-2的表征将增加我们对大肠杆菌发病机理的理解，并为新颖的治疗学。例如，PPI-2中的蛋白质与申请人和其他以前在铜绿假单胞菌中被利用的。在此奖项中获得的技能和指导将脚手架发展成一个独立的临床医生科学家，专注于革兰氏阴性的关键领域感染。