Antibiotic tolerance, bacterial persistence and ATP synthase / Tolérance aux antibiotiques, persistance bactérienne et ATP synthétase

抗生素耐受性、细菌持久性和 ATP 合成酶 / 抗生素耐受性、细菌持久性和 ATP 合成酶

• 批准号: RGPIN-2020-04811
• 负责人: Malouin, Francois
• 金额: $ 3.64万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740231
• 关键词: Antibiotic; tolerance; bacterial; persistence; ATP

Antibiotic resistance is now a well-documented problem worldwide. Other related issues such as bacterial persistence leading to antibiotic tolerance and evasion of the host immune defenses are less understood. Persistence by seemingly antibiotic-susceptible microorganisms is responsible for infection relapse and chronic manifestation of diseases. So-called difficult-to-treat infections (e.g., biofilms, infections of indwelling biomedical devices, lung infections in cystic fibrosis patients and recurrent infections in animals such as bovine mastitis) involve subpopulations of atypical bacteria that are not efficiently killed by antibiotics or the host immune system. Such atypical bacteria are called small-colony variants (SCVs) or Peristers depending on the mechanism by which they appear. The well-known pathogen Staphylococcus aureus can appear as a SCV. Compared to their commonly found normal counterparts, SCVs produce high amounts of protective biofilms, are tolerant to antibiotics and are capable of hiding and persisting within host epithelial cells. Many SCVs have mutations in the so-called respiratory chain that affect the enzyme (ATP synthase) responsible for producing the energy necessary for growth of the bacteria. Slow growing bacteria or dormant cells are tolerant to most antibiotics that usually kill actively growing bacteria. Fortunately, our research group has identified a natural product found in the tomato plant (tomatidine) that is able to kill S. aureus SCVs. The target of that new class of antibiotics is the ATP synthase. This discovery points to an essential function for the residual ATP synthase activity observed in SCVs. Unlike the S. aureus SCVs, other Persisters do not usually arise from mutations. There is abundant evidence that for example Escherichia coli persister cells arise from active mechanisms in response to a stress such as that caused by antibiotic exposure. An example of the mechanisms leading to E. coli persister cells involves the production of a bacterial peptide that sabotages its own respiratory chain and ATP production. This results in the generation of dormant cells tolerant to antibiotic action, a consequence similar to that observed in respiratory-deficient S. aureus SCVs. Based on our current understanding on how tomatidine acts on S. aureus SCVs, it is reasonable to suggest that Persisters may also be hypersusceptible to drugs inhibiting bacterial ATP synthase. The objectives of the proposed research is to characterize the mechanisms leading to the formation of SCVs and Persisters, to demonstrate that the ATP synthase is essential for these types of bacteria, and to demonstrate that the control and prevention measures we developed for S. aureus SCVs can be extended to other types of SCVs and Persisters. The low residual but apparently essential ATP synthase activity of SCVs might likewise represents the Achilles' heel of all persister cells from Gram positive or Gram negative pathogens.

抗生素耐药性现在是一个有据可查的世界性问题。其他相关的问题，如细菌持久性导致抗生素耐受性和逃避宿主免疫防御的了解较少。表面上对病原体敏感的微生物的持续存在是感染复发和疾病慢性表现的原因。所谓的难以治疗的感染（例如，生物膜、留置生物医学装置的感染、囊性纤维化患者的肺部感染和动物的复发性感染（例如牛乳腺炎）涉及不能被抗生素或宿主免疫系统有效杀死的非典型细菌亚群。这种非典型细菌被称为小菌落变体（SCV）或Peristers，这取决于它们出现的机制。众所周知的病原体金黄色葡萄球菌可以作为SCV出现。与它们常见的正常对应物相比，SCV产生大量的保护性生物膜，对抗生素具有耐受性，并且能够隐藏和持续存在于宿主上皮细胞内。许多SCV在所谓的呼吸链中发生突变，影响负责产生细菌生长所需能量的酶（ATP合酶）。生长缓慢的细菌或休眠细胞对大多数抗生素都有耐受性，而这些抗生素通常会杀死活跃生长的细菌。幸运的是，我们的研究小组已经确定了一种在番茄植物中发现的天然产物（番茄碱），能够杀死S。金黄色葡萄球菌SCV。这类新抗生素的目标是ATP合成酶。这一发现指出了在SCV中观察到的残留ATP合酶活性的基本功能。不像S。金黄色葡萄球菌SCV，其他Persisters通常不产生突变。有大量的证据表明，例如大肠杆菌的持留细胞来自于对诸如抗生素暴露引起的应激的反应的主动机制。并以E.大肠杆菌持留细胞涉及细菌肽的产生，该细菌肽破坏其自身的呼吸链和ATP产生。这导致产生耐受抗生素作用的休眠细胞，其结果类似于在抗生素缺陷的S.金黄色葡萄球菌SCV。基于我们目前对番茄碱如何作用于S.因此，通过观察金黄色葡萄球菌SCV，有理由认为Persisters也可能对抑制细菌ATP合酶的药物过敏。该研究的目的是描述导致SCV和Persisters形成的机制，以证明ATP合酶对这些类型的细菌是必不可少的，并证明我们为S.金黄色葡萄球菌SCV可以扩展到其他类型的SCV和Persisters。SCV的低残留但明显必需的ATP合酶活性可能同样代表来自革兰氏阳性或革兰氏阴性病原体的所有持留细胞的阿喀琉斯之踵。