Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
Antimicrob Agents Chemother. 2012 Nov;56(11):5782-9. doi: 10.1128/AAC.01125-12. Epub 2012 Aug 27.
Mycobacterium tuberculosis 18b, a streptomycin (STR)-dependent mutant that enters a viable but nonreplicating state in the absence of STR, has been developed as a simple model for drug testing against dormant bacilli. Here, we further evaluated the STR-starved 18b (SS18b) model both in vitro and in vivo by comparing the behavior of 22 approved and experimental tuberculosis drugs. Using the resazurin reduction microplate assay (REMA), rifampin (RIF), rifapentine (RPT), TMC207, clofazimine (CFM), and linezolid (LIN) were found to be active against SS18b in vitro, and their bactericidal activity was confirmed by determining the number of CFU. A latent 18b infection was established in mice, and some of the above-mentioned drugs were used for treatment, either alone or in combination with RIF. RIF, RPT, TMC207, CFM, and pyrazinamide (PZA) were all active in vivo, while cell wall inhibitors were not. A comparative kinetic study of rifamycin efficacy was then undertaken, and the results indicated that RPT clears latent 18b infection in mice faster than RIF. Intrigued by the opposing responses of live and dormant 18b cells to cell wall inhibitors, we conducted a systematic analysis of 14 such inhibitors using REMA. This uncovered an SS18b signature (CWPRED) that accurately predicted the activities of cell wall inhibitors and performed well in a blind study. CWPRED will be useful for establishing the mode of action of compounds with unknown targets, while the SS18b system should facilitate the discovery of drugs for treating latent tuberculosis.
结核分枝杆菌 18b 是一种链霉素（STR）依赖性突变株，在缺乏 STR 的情况下进入存活但非复制状态，已被开发为一种针对休眠杆菌的药物测试简单模型。在这里，我们通过比较 22 种已批准和实验性结核病药物，进一步在体外和体内评估了 STR 饥饿的 18b（SS18b）模型。使用 Resazurin 还原微板测定法（REMA），发现利福平（RIF）、利福喷汀（RPT）、TMC207、氯法齐明（CFM）和利奈唑胺（LIN）对 SS18b 在体外具有活性，并且通过确定 CFU 数证实了它们的杀菌活性。在小鼠中建立潜伏的 18b 感染，并单独或与 RIF 联合使用上述部分药物进行治疗。RIF、RPT、TMC207、CFM 和吡嗪酰胺（PZA）在体内均具有活性，而细胞壁抑制剂则没有。然后进行了 rifamycin 疗效的比较动力学研究，结果表明 RPT 比 RIF 更快地清除小鼠中的潜伏 18b 感染。由于对活细胞和休眠 18b 细胞对细胞壁抑制剂的反应相反感到好奇，我们使用 REMA 对 14 种此类抑制剂进行了系统分析。这揭示了 SS18b 特征（CWPRED），它可以准确预测细胞壁抑制剂的活性，并且在盲研究中表现良好。CWPRED 将有助于建立具有未知靶标的化合物的作用模式，而 SS18b 系统应该有助于发现治疗潜伏性结核病的药物。
