Establishing the Genetic Basis of Altered Drug Responses in Mycobacterium tuberculosis

总结 高水平的耐药性使结核病患者面临更大的治疗失败风险。 然而，患者也不能用明显的药物敏感菌株治疗，即使在 在临床试验环境中，依从性得到很好的监测。我们假设几十年来 药物暴露选择了药物介导的 清除，而不是通过传统的耐药性测试确定，这些 这些变化会影响患者的治疗效果。在之前的工作中，我们发现了 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 在类似宿主的环境条件下的时间依赖性杀伤测定。我们假设 这些突变倾向于治疗失败，即使它们也加速了 高水平耐药性的出现。为了验证这一假设，我们建议测试 假设突变与临床耐药和治疗失败有关， 在抗生素的存在下，队列改变了Mtb的存活率。为此，我们将构建 和表型是携带突变的同基因菌株的条形码文库， 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 与治疗失败相关的一种病毒引起小鼠感染模型中的治疗失败。 最后，由于许多耐药相关突变似乎导致多药耐药， 耐受性，我们将评估其对新抗生素和小 Mtb晚期发展阶段的分子。

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.