Targets for short-course TB therapy

描述(由申请人提供)：尽管有几种有效的抗生素可用，结核病(TB)仍然是传染病导致的主要死亡原因之一。结核分枝杆菌感染的治疗很困难，很大程度上是因为这种微生物具有惊人的能力，即使经过几个月或几年的抗生素治疗也能坚持下去，经常导致不完全绝育和疾病复发。治疗不当的必然后果是出现多药耐药菌株，这种菌株的治疗更具挑战性。虽然这种现象的临床重要性怎么强调都不为过，但从机理上理解治疗过程中细菌的持久性以及更有效地治疗这种感染的策略已被证明是难以捉摸的。我们建议使用两种新的遗传学方法在分子水平上理解抗生素的持久性，并识别代表更有效治疗目标的细菌途径。首先，我们将使用“转座子原位杂交”来识别在感染动物的抗生素治疗过程中持续存在所需的分枝杆菌基因。这些信息将被用来表征这种细菌在感染期间采用的抗生素“耐受”状态，并定义协同治疗的新靶点。作为一种平行的方法，我们将开发一种简便的系统，用于有条件地抑制结核分枝杆菌的基本基因，以确定在类似于体内环境的条件下，抑制导致细胞快速死亡的途径。我们希望这两种方法都能深入了解导致感染期间细菌对抗生素产生显著耐受性的细菌的代谢状态，并确定可能减少治疗结核病所需时间的药物的潜在靶点。短程疗法可改善获得有效治疗的机会，减少结核病的流行，并防止迅速出现耐药性，从而对当前的结核病大流行产生重大影响。结核病仍然是一个祸害，很大程度上是因为目前可用的抗生素只有在给药数月后才有效。我们将采用两种独立的方法来确定新药可以针对的细菌途径，以缩短有效治疗的持续时间。短程疗法可以通过使治疗更广泛地获得，并通过降低耐药菌株的出现速度来影响世界范围内的结核病流行。

DESCRIPTION (provided by applicant): Despite the availability of several effective antibiotics, tuberculosis (TB) remains one of the leading causes of death due to infectious disease. The treatment of Mycobacterium tuberculosis infections is difficult largely due to this organism's remarkable ability to persist in spite of months or years of antibiotic treatment, often resulting in incomplete sterilization and recurrent disease. The inevitable consequence of inadequate therapy is the emergence of multidrug-resistant strains, which are even more challenging to treat. While clinical importance of this phenomenon cannot be overstated, a mechanistic understanding of bacterial persistence during therapy and strategies to treat this infection more effectively has proven elusive. We propose to employ two new genetic methodologies to understand antibiotic persistence at the molecular level, and to identify bacterial pathways that represent targets for a more effective therapeutics. First, we will employ "transposon-site hybridization" to identify mycobacterial genes that are required for persistence during antibiotic treatment of infected animals. This information will be used to characterize the antibiotic "tolerant" state adopted by this bacterium during infection and to define novel targets for synergistic therapies. As a parallel approach, we will develop a facile system for conditionally inhibiting essential genes of M. tuberculosis in order to define pathways whose inhibition results in rapid cell death under conditions similar to the in vivo environment. We expect both of these approaches to provide insight into the metabolic state of the bacterium that is responsible for its remarkable antibiotic tolerance during infection, and to identify potential targets for drugs that could reduce the time required to treat TB. Short-course therapy could have a dramatic effect on the current TB pandemic by improving access to effective treatment, reducing the prevalence of TB, and preventing the rapid emergence of drug resistance. Tuberculosis remains a scourge largely because currently available antibiotics are effective only after many months of administration. We will pursue two independent approaches to identify bacterial pathways that could be targeted by new drugs to shorten the duration of effective treatment. Short-course therapy could impact the worldwide tuberculosis epidemic both by making treatment more widely available and by reducing the rate at which drug-resistant strains emerge.