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

• 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
• 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

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.

摘要 侵袭性革兰氏阴性细菌感染的临床结果由患者的相互作用决定， 治疗和细菌变数。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预后知之甚少。这是一个 在理解微生物发病机制方面存在重要差距，并限制了识别关键药物靶点的能力 人类的发病机制。为了解决这个问题，长期的目标是询问细菌的发病机制 通过定义细菌遗传变异对革兰氏阴性患者预后的影响 菌血症。这一知识可以被用来确定新的治疗方法。职业发展计划 反映了这一长期目标，因为重点是发展量化和实验室专业知识，以独立 识别和探索细菌遗传学和患者预后之间的联系。这件事的目的是 建议对大肠杆菌中存在的两个假定的致病岛(PPI)进行表征，这两个岛是 它们在发病机制中的作用和作为药物靶点的潜力很有希望。这两个PPI由 申请和编码与III型分泌系统(T3SS)结构装置(PPI-1)同源的基因 和转位/粘附素(PPI-2)。PPI-1/PPI-2在典型的实验室菌株中不存在，因此 还没有得到显著的研究。PPI-1/PPI-2的存在与患者死亡率增加相关 和PPI-1/PPI-2的缺失允许补体介导的对大肠杆菌的杀灭 血清和受损的大肠杆菌-宿主细胞相互作用(减少侵袭)。此外，PPI-1/PPI-2作为 提高识别高死亡风险患者的能力的预后生物标记物。中心假设是 PPI-1和PPI-2共同发挥T3SS的作用，介导补体介导的血清抵抗和 组织侵袭性对患者预后的影响，PPI-1/PPI-2的存在提供了预后价值 大肠埃希菌BSI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如何 影响毒力以影响患者预后，以及2)将PPI-1和PPI-2基因型值定义为预后 大肠杆菌菌血症的生物标志物。SA1将确定PPI-1/PPI-2如何介导补体抵抗 激活，验证PPI-1/PPI-2是一个功能性的T3SS，并确定血清杀伤的相对贡献 与T3SS对毒力的作用。SA2将使用现有的外部验证队列来表明 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局的预后模型。 PPI-1/PPI-2的特性将加深我们对大肠杆菌致病机理的理解，并为 新的治疗方法。例如，PPI-2中的一种蛋白质与申请人和 其他以前在铜绿假单胞菌中开采的。在该奖项期间获得的技能和指导 支架是否会发展成为专注于革兰氏阴性杆菌关键领域的独立临床医生和科学家 感染。