Novel Screen to Assess Bactericidal Activity of Compounds Against Non-replicating Mycobacterium abscessus
Novel Screen to Assess Bactericidal Activity of Compounds Against Non-replicating Mycobacterium abscessus
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DOI：
10.3389/fmicb.2018.02417
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发表时间：
2018-10-10
影响因子：
5.2
通讯作者：
Parish, Tanya
中科院分区：
文献类型：
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作者：
Berube, Bryan J.;Castro, Lina;Parish, Tanya
脓肿分枝杆菌感染在世界范围内呈上升趋势。目前的药物治疗方案在很大程度上是无效的，然而目前针对脓肿分枝杆菌的药物开发渠道却少得惊人。脓肿分枝杆菌的传统发现工作是评估一种新药在营养丰富的生长条件下抑制细菌生长的能力，但这并不能预测临床应用时的影响。体外和体内活性之间的脱节可能是由于细菌对感染期间遇到的环境条件的遗传和生理适应；这包括低氧张力和营养性饥饿。我们试图通过建立一种在非复制条件下鉴定对脓肿分枝杆菌具有杀菌活性的新化合物的试验来填补药物发现管道中的空白。我们开发并验证了一种利用营养饥饿产生非复制状态的新筛选方法。我们使用alamarBlue (R)来测量代谢活性，并证明这与这些条件下的细菌活力相关。我们优化了关键参数并证明了重现性。通过该试验，我们确定氯硝柳胺对非复制杆菌具有杀菌作用，突出了其在脓肿分枝杆菌治疗方案中的潜力。相比之下，目前临床上用于治疗脓肿分枝杆菌感染的大多数其他药物完全无效，这可能解释了它们疗效差的原因。因此，我们的分析允许在使用与体内更相关的条件的模型中快速鉴定杀菌化合物。这种筛选可以以高通量的方式来识别具有提高疗效的特性的新型药物，同时也缩短了治疗时间。
Mycobacterium abscessus infections are increasing worldwide. Current drug regimens are largely ineffective, yet the current development pipeline for M. abscessus is alarmingly sparse. Traditional discovery efforts for M. abscessus assess the capability of a new drug to inhibit bacterial growth under nutrient-rich growth conditions, but this does not predict the impact when used in the clinic. The disconnect between In vitro and in vivo activity is likely due to the genetic and physiological adaptation of the bacteria to the environmental conditions encountered during infection; these include low oxygen tension and nutrient starvation. We sought to fill a gap in the drug discovery pipeline by establishing an assay to identify novel compounds with bactericidal activity against M. abscessus under non-replicating conditions. We developed and validated a novel screen using nutrient starvation to generate a non-replicating state. We used alamarBlue (R) to measure metabolic activity and demonstrated this correlates with bacterial viability under these conditions. We optimized key parameters and demonstrated reproducibility. Using this assay, we determined that niclosamide was bactericidal against non-replicating bacilli, highlighting its potential to be included in M. abscessus regimens. In contrast, most other drugs currently used in the clinic for M. abscessus infections, were completely inactive, potentially explaining their poor efficacy. Thus, our assay allows for rapid identification of bactericidal compounds in a model using conditions that are more relevant in vivo. This screen can be used in a high-throughput way to identify novel agents with properties that promise an increase in efficacy, while also shortening treatment times.