Establishing the Genetic Basis of Altered Drug Responses in Mycobacterium tuberculosis

建立结核分枝杆菌药物反应改变的遗传基础

基本信息

批准号：
10390301
负责人：
SARAH FORTUNE
金额：
$ 99.03万
依托单位：
HARVARD MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-04-18 至 2024-03-31
项目状态：
已结题

项目摘要

Summary High-level drug resistance puts TB patients at increased risk of treatment failure. However, patients also fail treatment with apparently drug susceptible strains even in clinical trial settings where compliance is well monitored. We postulate that decades of drug exposure have selected for bacterial strains that have alterations in drug-mediated clearance that are not identified by conventional drug resistance testing and that these changes put compromise patient outcomes. In previous work, we identified mutations that alter bacterial drug susceptibility in ways that are not identified by conventional clinical resistance testing but are revealed by assaying bacterial drug responses using time-dependent killing assays under host-like environmental conditions. We hypothesize that these mutations predispose to treatment failure even as they also accelerate the emergence of high-level drug resistance. To test this hypothesis, we propose to test the hypothesis that mutations associated with resistance and treatment failure in clinical cohorts alter Mtb survival in the presence of antibiotics. For this aim, we will construct and phenotype a barcoded library of isogenic strains carrying mutations identified in our analyses of clinical strains as associated with drug resistance or treatment failure. We will test the hypothesis that the drug resistance-associated mutations and mutations associated with treatment failure cause treatment failure in a mouse model of infection. Finally, because many resistance associated mutations appear to cause multidrug tolerance, we will assess their effects on the efficacy of new antibiotics and small molecules in late stage development for Mtb.

概括高水平的耐药性使结核病患者治疗失败的风险增加。然而，即使在明显的药物敏感菌株治疗中，患者也失败了。依从性受到良好监控的临床试验环境。我们假设几十年药物暴露选择了具有药物介导改变的细菌菌株常规耐药性测试无法识别的清除率，并且这些变化会损害患者的治疗结果。在之前的工作中，我们发现了突变以常规方法无法识别的方式改变细菌药物敏感性临床耐药性测试，但通过使用测定细菌药物反应来揭示在类似宿主的环境条件下进行时间依赖性杀伤测定。我们假设这些突变容易导致治疗失败，即使它们也会加速出现高度耐药性。为了检验这个假设，我们建议检验假设突变与临床耐药性和治疗失败相关在抗生素存在的情况下，队列会改变结核分枝杆菌的存活率。为了这个目标，我们将建设并对携带我们鉴定的突变的同基因菌株的条形码文库进行表型分析分析与耐药性或治疗失败相关的临床菌株。我们将检验耐药相关突变和突变的假设与治疗失败相关导致小鼠感染模型治疗失败。最后，因为许多耐药性相关突变似乎会导致多种药物耐受性，我们将评估它们对新抗生素和小抗生素疗效的影响结核分枝杆菌处于后期开发阶段的分子。