Determining the value of PBP 7/8 as an antimicrobial target for XDR-A. baumannnii

确定 PBP 7/8 作为 XDR-A 抗菌靶点的价值。

• 批准号: 10516081
• 负责人: THOMAS A RUSSO
• 金额: --
• 依托单位: VA WESTERN NEW YORK HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-10-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10516081
• 关键词: Abscess; Acinetobacter baumannii; Active Sites; Acute; Affect; Anti-Bacterial Agents; Antimicrobial Resistance; Ascites; Attention; Bacillus; Binding; Biological Assay; Carbapenems; Ceftazidime; Cells; Cellular Structures; Characteristics; Complement; Cytolysis; Data; Development; Drug Targeting; Drug resistance; ESKAPE pathogens; Elements; Endopeptidases; Escherichia coli; Generations; Goals; Growth; Health; Health Care Costs; Healthcare; Homologous Gene; Host Defense; Human; In Vitro; Incidence; Infection; Insecta; Laboratories; Lactams; Location; Long-Term Care; Mediating; Meropenem; Methods; Microbial Biofilms; Military Personnel; Modeling; Molecular Weight; Monoclonal Antibodies; Monoclonal Antibody Therapy; Morbidity - disease rate; Muramidase; Pathogenicity; Penicillin Binding Protein 2; Penicillin Binding Protein 4; Penicillin-Binding Proteins; Penicillins; Peptidoglycan; Performance; Permeability; Pneumonia; Population; Predisposition; Prevention approach; Process; Production; Rattus; Reporting; Research Personnel; Resistance; Resistance development; Salmonella; Serum; Specificity; Structure; Subcutaneous abscess; Tazobactam; Testing; Tobramycin; Veterans; Work; antimicrobial; antimicrobial drug; assay development; bactericide; capsule; cost; drug development; drug resistant pathogen; extensive drug resistance; high throughput screening; in vivo; inhibitor; insight; military veteran; molecular mass; mortality; novel strategies; pathogen; periplasm; preclinical study; resistant strain; small molecule; small molecule libraries; tool; trait; transposon sequencing

Anticipated Impacts on Veterans Health Care. The incidence of infections due to highly resistant Acinetobacter baumannii is increasing. True pan drug resistant (PDR) strains have been reported. Unfortunately, the newly approved antimicrobials ceftolozane-tazobactam, ceftazidime-avibactam, and meropenem/vaborbactam are poorly active against resistant A. baumannii. The need to identify new antimicrobials active against A. baumannii is pressing. Background. We have demonstrated that the A. baumannii low molecular mass (LMM) penicillin binding protein 7/8 (PBP 7/8) is essential in vivo (i.e., required for bacterial survival in a host) in rat pneumonia and subcutaneous abscess infection models, and is required for survival in human serum and ascites. Our initial studies on PBP 7/8 were performed in an antimicrobial sensitive strain AB307-0294. These findings have since been confirmed with the extensively drug resistant (XDR) strain HUMC1. Since our initial observation other investigators, using INseq and Tn-seq, have shown that PBP 7/8 is needed for A. baumannii survival in the Galleria mellonella insect infection model and serum respectively. PBP 7/8 has many characteristics that support its potential as a high value drug target. However, based on studies in rich laboratory medium, LMM PBPs including PBP 7/8 have been perceived to be non-essential. As a result, PBP 7/8 have received scant attention as an antibacterial target and has not been considered for A. baumannii. However, our data contradicts this paradigm and endorses the need for additional studies on PBP 7/8 in XDR A. baumannii. Therefore, our objective is to validate PBP 7/8 as a drug target, delineate mechanisms that mediate its ex vivo and in vivo essentiality, and to identify compounds that inactivate PBP 7/8. Objectives and Methods. To achieve these objectives, studies on PBP 7/8 will be extended to include additional XDR strains of A. baumannii to confirm our findings are generalizable (aim 1). Aim 1 also will also explore mechanisms by which PBP 7/8 enables growth/survival of A. baumannii ex vivo and in vivo and identify the innate host defense factors it protects against. Increasing data support the need to treat infections due to XDR isolates with multiple agents, thereby increasing efficacy and protecting against the development of resistance. Our demonstration that the loss of PBP 7/8 production increases susceptibility to complement and lysozyme mediated bactericidal activity and changes cell structure supports the hypothesis that the inability to produce PBP 7/8 affects permeability, a critical factor in the intrinsic antimicrobial resistance of A. baumannii. Therefore, an additional goal of this proposal will be to assess the whether the loss of PBP 7/8 production enhances the activity of adjunctive therapy with antimicrobials and/or monoclonal antibodies directed against the capsule (aim 2). Additional studies in aim 2 will assess whether the loss of PBP 7/8 affects the production of other PBPs and ampC expression. These data will generate additional mechanistic insights into the consequences of not being able to produce PBP 7/8. Lastly, aim 3 will begin the process of identifying a “tool” compound that is active against PBP 7/8. A live wild-type XDR strain will be screened against a chemical library to identify compounds directed against PBP 7/8 that possess bactericidal activity. Additional orthogonal assays will establish specificity, determine their quality, and prioritize identified inhibitors for downstream optimization and pre-clinical studies. Deliverables from this proposal will validate the paradigm shift on the value of PBP 7/8 as an antimicrobial target and open an untapped venue for the development of a new class of antimicrobial agents against this XDR pathogen.

对退伍军人卫生保健的预期影响。由于高度抗性引起的感染事件 鲍曼尼杆菌正在增加。据报道了真正的PAN药物抗药性（PDR）菌株。 不幸的是，新批准的抗菌菌Ceftolozane-tazobactam，ceftazidime-avibactam和 MeropeNem/vaborbactam对抗性抗体抗体的活性很差。需要识别新的 抗微生物抗菌对鲍曼尼曲霉的活跃。 背景。我们已经证明了鲍曼尼曲霉的低分子质量（LMM）青霉素结合 蛋白7/8（PBP 7/8）在大鼠肺炎和 皮下脓肿感染模型，是人血清和腹水中生存所必需的。我们的最初 对PBP 7/8的研究是在抗菌敏感菌株AB307-0294中进行的。这些发现有 由于我们被广泛的耐药性（XDR）菌株HUMC1证实。自我们最初的观察以来 使用Inseq和TN-Seq的其他研究人员已经表明，A。Baumannii中需要PBP 7/8 梅洛尼亚氏菌的绝缘感染模型和血清。 PBP 7/8具有许多特征 支持其作为高价值药物目标的潜力。但是，基于在丰富的实验室培养基中的研究，LMM 包括PBP 7/8在内的PBP被认为是非必需的。结果，PBP 7/8获得了很少的 注意作为抗菌靶标，尚未考虑鲍曼尼曲霉。但是，我们的数据 与此范式相矛盾，并认可在XDR A. Baumannii中对PBP 7/8的其他研究。 因此，我们的目标是验证PBP 7/8作为药物靶标，描述了介导其EX的机制 体内和体内的本质性，并确定使PBP 7/8灭活的化合物。 目标和方法。为了实现这些目标，对PBP 7/8的研究将扩展到包括 A. baumannii的其他XDR菌株以确认我们的发现是可推广的（AIM 1）。 AIM 1也将 探索PBP 7/8实现A. baumannii ex Vivo和体内和体内和生存的机制 确定先天的宿主防御因素。增加数据支持治疗感染的需求 由于具有多种代理的XDR分离株，因此提高了效率并防止开发 阻力。我们的证明是PBP 7/8生产的损失增加了完成的易感性 溶菌酶介导的细菌活性并改变细胞结构，这支持了以下假设。 无法产生PBP 7/8会影响渗透性，这是A的内在抗菌耐药性的关键因素。 鲍曼尼。因此，该提案的另一个目标是评估PBP 7/8的损失是否 生产增强了用抗菌和/或单克隆抗体的辅助治疗的活性 针对胶囊（AIM 2）。 AIM 2中的其他研究将评估PBP 7/8的丧失是否影响 其他PBP和AMPC表达的产生。这些数据将产生其他机械见解 无法产生无法产生PBP 7/8的后果。最后，AIM 3将开始识别的过程 与PBP 7/8相对活性的“工具”化合物。将对活的野生型XDR菌株进行筛选 化学文库以识别针对具有细菌活性的PBP 7/8的化合物。额外的 正交分析将确定特异性，确定其质量并确定确定的抑制剂 下游优化和临床前研究。该提案的可交付成果将验证范式 将PBP 7/8作为抗菌靶标的价值转移，并为开发未开发的场地开放 针对这种XDR病原体的一类新的抗菌剂。