Understanding B-Lactam Resistance in Acinetobacter baumannii

了解鲍曼不动杆菌中的 B-内酰胺耐药性

• 批准号: 10005100
• 负责人: ROBERT A. BONOMO
• 金额: $ 38.63万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10005100
• 关键词: Acinetobacter; Acinetobacter baumannii; Active Sites; Address; Affect; Amides; Antibiotic Resistance; Antibiotics; Bacteria; Binding Sites; Biochemical; Blood; Boronic Acids; Carbapenems; Catalysis; Cefepime; Cephalosporinase; Chemistry; Clinical; Collection; Common Core; Development; Enzymes; Fright; Genes; Genetic; Genetic Screening; Goals; Hot Spot; Kinetics; Lead; Microbiology; Modern Medicine; Multi-Drug Resistance; Multidrug-resistant Acinetobacter; Mutation; Patients; Pharmacologic Substance; Phenotype; Prevalence; Publishing; Resistance; Respiratory Tract Infections; Scourge; Series; Siderophores; Stream; Structure; Structure-Activity Relationship; Sulbactam; Therapeutic; Therapeutic Agents; Triazoles; Variant; Vertebral column; World Health Organization; bacterial fitness; base; beta-Lactam Resistance; beta-Lactamase; beta-Lactams; carbapenem resistance; carbapenemase; clinically relevant; combat; design; efflux pump; falls; genetic approach; genome sequencing; high throughput screening; in vitro activity; inhibitor/antagonist; innovation; insight; news; novel; novel strategies; novel therapeutics; overexpression; pathogen; priority pathogen; resistant strain; scaffold; therapeutic target; transposon sequencing; whole genome

The WHO lists Acinetobacter baumannii (Ab) as the most problematic pathogen infecting patients. In this renewal, we will build upon our successful accomplishments in our first two R01s in which we developed an entirely new class of boronic acid transition state inhibitors (BATSIs), explored the structure activity relationships (SAR) of the chromosomal cephalosporinase of Ab, ADC-7, as well as the class D carbapenemases OXA-23, - 24/40 and -66/51, and defined the efflux pumps governing antibiotic resistance. Herein, we will embark upon innovative ways to overcome β-lactam resistance by proposing two novel approaches. Firstly, we propose that structural and mechanistic similarities exist between class C and D β-lactamases present in Acinetobacter spp. that reveal a common intermediate. This notion will drive efforts to synthesize carbapenem and cephem based BATSIs that will inactivate both β-lactamase classes. Secondly, we advance that chromosomal blaADC and blaOXA overexpression in resistant isolates creates new cellular vulnerabilities that can be identified by genetic approaches such as Tn-Seq. These unique vulnerabilities will be exploited in high-throughput screens (HTS) to identify novel compounds that specifically target highly β-lactam resistant isolates. The novel targets and new inhibitors identified could lead to the “next generation” of therapeutics that overcome high-level β-lactam resistant Ab and avoid the indiscriminate killing of all bacteria. To meet these goals, we will build upon our insights into the structures of ADC and OXA β-lactamases and the chemistry of α-triazoles and amide bioisostere BATSIs to explore the SAR of these two series of compounds that will identify inhibitory activity toward both class C and D β-lactamases. As carbapenems are known to be both substrate (class D) and inhibitors (class C) of these β- lactamases, we will first synthesize novel BATSI compounds based upon a carbapenem backbone, as this scaffold provides a common core from which to build a broad-spectrum inhibitor of both C and D β-lactamases. These new inhibitors will be evaluated microbiologically, biochemically, and structurally against emerging clinical variants of ADC and OXA β-lactamases. We will then validate the selected inhibitors against a panel of clinical strains. Simultaneously, we will also use Tn-Seq to identify mutations that confer a synthetic lethal phenotype in an Ab strain overexpressing the chromosomal blaADC or blaOXA β-lactamase. A genetic screen will be performed to confirm that the genes identified confer a synthetic lethal phenotype. Lastly, we will utilize high throughput screening (HTS) to identify new therapeutic agents that impact the interplay of chromosomal blaADC or blaOXA expression and bacterial viability. The current prevalence of MDR and pan-resistant strains of Ab, combined with the lack of new antibiotics, underscores the critical need for the development of novel therapeutics to combat this bacterium. Our goal is to design novel cross-class inhibitors that exploit the commonality of catalysis as well as agents that affect bacterial fitness and viability. We anticipate the novel BATSIs discovered and agents found in the HTS will lead to entirely innovative approaches to treating MDR Ab.

世卫组织将鲍曼尼（AB）列为最有问题的病原体感染患者。在这个 更新，我们将在我们开发的前两个R01中取得成功的基础 全新的硼酸过渡状态抑制剂（BATSIS）探索了结构活动关系 AB，ADC-7的染色体头孢菌素酶的（SAR）以及D类碳青霉酶OXA-23， - 24/40和-66/51，并定义了控制抗生素耐药性的外排泵。在这里，我们将开始 通过提出两种新颖的方法来克服β-内酰胺抗性的创新方法。首先，我们建议 C杆菌属中存在的C类和Dβ-内酰胺酶之间存在结构和机械相似性。 这揭示了一个常见的中间体。这个概念将推动综合碳青霉烯和头孢菌素的努力 蝙蝠会使两个β-内酰胺酶类别失活。其次，我们推进了染色体Blaadc和Blaoxa 抗性分离株中的过表达会产生新的细胞漏洞，可以通过遗传来识别 诸如tn-seq之类的方法。这些独特的漏洞将在高通量屏幕（HTS）中探讨 鉴定新的化合物，这些化合物专门针对高度β-内酰胺抗性分离株。新颖的目标和新目标 确定的抑制剂可能导致克服高级β-内酰胺抗性的“下一代”治疗剂 AB并避免滥用所有细菌。为了实现这些目标，我们将基于我们的见解 ADC和OXAβ-内酰胺酶的结构以及α-三唑和酰胺生物酶壳蝙蝠的化学 探索这两个系列化合物的SAR，这些化合物将鉴定对C类抑制活性 β-内酰胺酶。由于碳青霉烯既是这些β-的底物（D类）和抑制剂（C类）（C） 乳糖酶，我们将首先根据碳碳纤维链链合成新型的蝙蝠质化合物，因此 脚手架提供了一个共同的核心，可以从中构建C和Dβ-内酰胺酶的广谱抑制剂。 这些新的抑制剂将在微生物学，生化和结构上对出现的临床进行评估 ADC和OXAβ-内酰胺酶的变体。然后，我们将针对临床面板验证选定的抑制剂 菌株。同时，我们还将使用tn-seq识别会导致合成致命表型的突变 过表达过度表达染色体BlaADC或Blaoxaβ-内酰胺酶的AB菌株。将进行遗传屏幕 为了确认基因确定了会议的合成致命表型。最后，我们将利用高吞吐量 筛选（HTS）以识别影响染色体Blaadc或Blaoxa相互作用的新治疗剂 表达和细菌生存能力。 AB的MDR和泛抗菌菌株的当前患病率与 缺乏新的抗生素，强调了开发新疗法以对抗的关键需求 这个细菌。我们的目标是设计新颖的跨层抑制剂，以利用催化的共同点 作为影响细菌适应性和生存能力的药物。我们预料到发现的新颖的袭击者，并且发现了特工 在HTS中，将导致完全创新的方法来治疗MDR AB。