Exploitation of multiple heteroresistance for effective antibiotic combination therapy

项目摘要/摘要 抗生素耐药性是我们这个时代最严重的医学挑战之一。这场危机使病人处于危险之中。 无法治愈的细菌感染，并威胁依赖抗生素的现代医学的重大进步 (移植、化疗等)。美国每年至少有200万例耐药感染病例， 导致超过23,000人死亡。据估计，如果不采取重大行动，全球每年因 到2050年，这些感染人数将达到1000万人，超过预测的癌症死亡率。不幸的是， 一些细菌，包括耐碳青霉烯肠杆菌科(CRE)的特定菌株和 耐碳青霉烯类鲍曼不动杆菌(螃蟹)现在对所有可用的抗生素都有抗药性， 基本上无法治愈。在这种情况下，抗生素的组合被用来试图克服 对个别药物产生抗药性，但只是零星有效。目前尚不清楚组合何时起作用以及为什么起作用。 因此，临床医生缺乏合理的科学理由来选择将抗生素纳入这些方案。 我们的研究揭示了一种与抗生素协同作用不同的意想不到的原理，可以用于 设计个性化的组合来杀灭包括泛耐药菌株在内的临床细菌分离株。 这种联合治疗方法是基于异质性耐药，这是一种神秘的抗生素耐药性形式 其中细菌分离株含有一个抗性亚群，该亚群可以在存在的情况下快速复制 抗生素，而大多数易感人群被杀死。然而，我们现在展示了，当组合在一起时，两个 对特定菌株具有异质性耐药的抗生素会杀死细菌，因为每种药物都会抑制亚群 抵抗另一种的细胞[Band等人，自然微生物学，2019]。因此，对多个 抗生素(“多重异源耐药”)可以作为细菌的致命弱点和有效的基础 联合疗法。重要的是，这种方法使用了FDA批准的现有抗生素，可以 立即受雇于诊所。这种改变模式的联合治疗方法具有 可能会产生重大的翻译影响，但必须首先进行广泛和彻底的审问。在这里，我们 建议使用一组来自佐治亚州监测倡议的强大的CRE和螃蟹临床分离株来 对多种抗生素进行异源耐药试验。这将允许在体外和体内进行选择 测试以多重异质电阻为目标的组合。我们将进一步研究两国之间的关系 多个异抗菌株中的抗性亚群，以及执行动态流动实验 测定有效组方的药代动力学和药效学。这项研究具有 可能为临床医生提供一种合理和可预测的方法来开出有效的抗生素 用于治疗细菌感染的组合，包括目前被认为无法治疗的感染。

Project Summary/Abstract Antibiotic resistance is one of the most serious medical challenges of our time. This crisis puts patients at risk of untreatable bacterial infections and threatens major advances of modern medicine that rely on antibiotics (transplants, chemotherapy, etc). There are at least 2 million antibiotic resistant infections each year in the US, leading to over 23,000 deaths. It is estimated that without significant action, worldwide annual mortality due to these infections will reach 10 million by 2050, surpassing the predicted mortality from cancer. Unfortunately, some bacteria, including specific isolates of carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-resistant Acinetobacter baumannii (CRAB), are now resistant to all available antibiotics and are essentially untreatable. In such instances, combinations of antibiotics are employed to try to overcome the resistance to individual drugs, but are only sporadically effective. When and why combinations work is unclear, and clinicians therefore lack a sound scientific rationale for choosing antibiotics to include in these regimens. Our research has revealed an unexpected principle, distinct from antibiotic synergy, that can be used to design personalized combinations to kill clinical bacterial isolates including pan-resistant strains. This combination therapy approach is based on heteroresistance, an enigmatic form of antibiotic resistance in which a bacterial isolate harbors a resistant subpopulation that can rapidly replicate in the presence of an antibiotic, while the majority susceptible population is killed. However, we now show that when combined, two antibiotics to which a given strain is heteroresistant, kill the bacteria as each drug inhibits the subpopulation of cells resistant to the other [Band et al, Nature Microbiology, 2019]. Thus, heteroresistance towards multiple antibiotics (“multiple heteroresistance”) can be exploited as a bacterial Achilles' heel and the basis of effective combination regimens. Importantly, this method employs existing FDA-approved antibiotics and can be employed in the clinic immediately. This paradigm-shifting approach to combination therapy has the potential to have a major translational impact, but must first be broadly and thoroughly interrogated. Here, we propose to use a robust set of CRE and CRAB clinical isolates from a Georgia-based surveillance initiative to test for heteroresistance to a wide range of antibiotics. This will allow the selection and in vitro and in vivo testing of combinations targeting multiple heteroresistance. We will further study the relationship between the resistant subpopulations in multiple heteroresistant isolates, as well as performing dynamic flow experiments to determine the pharmacokinetics and pharmacodynamics of effective combinations. This research has the potential to provide clinicians with a rational and predictable method with which to prescribe effective antibiotic combinations to treat bacterial infections, including those currently considered untreatable.