Isolating novel actinomycetes for antibiotic discovery

分离新型放线菌以发现抗生素

• 批准号: 8049200
• 负责人: Losee Lucy Ling
• 金额: $ 99.96万
• 依托单位: NOVOBIOTIC PHARMACEUTICALS, LLC
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-15 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8049200
• 关键词: Acinetobacter; Actinobacteria class; Acute; Agar; Animal Model; Antibiotics; Bacteria; Burkholderia; Collection; Communities; Ensure; Enterobacter; Evaluation; Goals; Growth; Health; Hospitals; Human; Hyphae; In Situ; In Vitro; Infection; Klebsiella; Klebsiella pneumonia bacterium; Lead; Libraries; Lung; Membrane; Methods; Modeling; Multi-Drug Resistance; Mus; Pharmaceutical Preparations; Phase; Probability; Pseudomonas; Public Health; Resistance; Running; Schedule; Slice; Soil; Source; Sterility; Structure; Technology; Toxic effect; Validation; antimicrobial; meetings; microbial; microorganism; new technology; next generation; novel; pathogen; programs

DESCRIPTION (provided by applicant): The goal of this project is to discover novel broad-spectrum antibiotics acting against critically important human pathogens. The unmet need is especially acute for Gram negative pathogens, where we are rapidly running out of options for treating multidrug resistant species of Pseudomonas, Acinetobacter, Burkholderia, Klebsiella and Enterobacter. This is a challenging goal, since the last novel class of broad-spectrum antibiotics was discovered 40 years ago. NovoBiotic has a proprietary technology capable of meeting this challenge. We will obtain new antimicrobials from a previously inaccessible source - uncultured microorganisms that make up 99% of the total microbial diversity. In Phase I, we developed a trap for specific capture and growth of uncultured Actinomycetes. Most antibiotics derive from culturable representatives of this group of bacteria. The trap is a sterile slice of agar sandwiched between semi-permeable membranesthat is inserted into soil. Actinomycetes produce hyphae which enable them to penetrate into the trap through the pores in the membrane and form pure colonies. Many uncultured species that initially grow in situ are then capable of growing under regular conditions in vitro. The aims of Phase I were to assemble a collection of 1,000 novel Actinomycetes using the trap method, screen them for antimicrobial activity and dereplicate 50 of them. We achieved these milestones ahead of schedule and have in place a robust technology that will enable us to discover broad-spectrum antibiotics in this Phase II project. Half of the Actinomycetes captured by the trap are new, an impressive indication of the usefulness of this method. Of the 92 compounds that were dereplicated, we discovered two new antibiotics, one of which belongs to a novel class, glycosylated macrolactams. This suggests a probability of discovery ~10-2, compared to the current estimate of 10-7 for novel compounds from conventional culturable strains. The hit rate for compounds with broad-spectrum activity from this pilot library was 1%, and 1 of these 12 dereplicated antimicrobials is a potentially novel antibiotic. These findings strongly suggest that an expanded discovery effort in Phase II will lead to a considerable number of new broad-spectrum antimicrobials. In this project, we will screen up to 750,000 trap isolates, which should produce ~30 new broadspectrum compounds. There in vitro validation and structure determination will be followed by evaluation for toxicity in an animal model, and for efficacy in a murine model of K. pneumonia pulmonary infection. The end result of Phase II will be 2-3 validated novel broad-spectrum leads. These will be developed into drugs in the next phase of the program.

描述（由申请人提供）：该项目的目标是发现新的广谱抗生素，用于对抗至关重要的人类病原体。革兰氏阴性病原体的需求未得到满足的情况尤其严重，我们正在迅速耗尽治疗假单胞菌、不动杆菌、伯克霍尔德氏菌、克雷伯氏菌和肠杆菌等多重耐药物种的选择。这是一个具有挑战性的目标，因为最后一类新型广谱抗生素是在40年前发现的。NovoBiotic拥有能够应对这一挑战的专有技术。我们将从以前无法获得的来源获得新的抗菌剂-未培养的微生物，占微生物多样性总数的99%。在第一阶段，我们开发了一种专门捕获和生长未培养放线菌的陷阱。大多数抗生素来源于这类细菌的可培养代表。诱捕器是将一片无菌琼脂夹在半透膜之间，插入土壤中。放线菌产生菌丝，使它们能够通过膜上的孔渗透到捕集器中，形成纯菌落。许多未培养的物种最初在原位生长，然后能够在体外正常条件下生长。第一阶段的目标是利用诱捕法收集1000种新型放线菌，筛选它们的抗菌活性，并对其中的50种进行去复制。我们提前实现了这些里程碑，并拥有一项强大的技术，使我们能够在这个第二阶段项目中发现广谱抗生素。陷阱捕获的放线菌中有一半是新的，这令人印象深刻地表明了这种方法的有效性。在92个被去复制的化合物中，我们发现了两个新的抗生素，其中一个属于一个新的类别，糖基化大内酰胺。这表明从传统可培养菌株中发现新化合物的概率为10-2，而目前估计为10-7。该中试文库中具有广谱活性的化合物的命中率为1%，这12种去复制抗菌素中有1种是潜在的新型抗生素。这些发现有力地表明，在第二阶段扩大发现工作将导致相当数量的新的广谱抗菌素。在这个项目中，我们将筛选多达75万个陷阱分离物，这将产生约30个新的广谱化合物。在体外验证和结构确定之后，将在动物模型中评估毒性，并在肺炎克雷伯菌肺部感染的小鼠模型中评估有效性。第二阶段的最终结果将是2-3个经过验证的新型广谱导联。这些将在下一阶段被开发成药物。