Shi Jin, Liu Yuanyuan, Wu Tuoya, Li Lu, Han Shujing, Peng Xiao, Shang Yuanyuan, Guo Yongli, Pang Yu, Gao Mengqiu, Lu Jie
Department of Tuberculosis, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis & Thoracic Tumor Research Institute , Beijing, China.
Beijing Key Laboratory for Pediatric Diseases of Otolaryngology, Head and Neck Surgery, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health , Beijing, China.
Microbiol Spectr. 2023 Aug 30;11(5):e0009023. doi: 10.1128/spectrum.00090-23.
The 2022 World Health Organization guidelines recommend use of two core anti-tuberculosis (TB) drugs, bedaquiline (BDQ) and clofazimine (CFZ), for treatment of drug-resistant (DR)-TB. However, several mutated (MTB) genes, conferring BDQ and CFZ resistance, have been reported that predominantly arose from sporadic mutations that have not been comprehensively characterized. Herein, MTB clinical isolates collected from drug-susceptible (DS)-, multidrug-resistant (MDR)-, and extensively drug-resistant (XDR)-TB patients were cultured with BDQ or CFZ to generate progeny strains with resistance to these drugs. Progeny strains exposed to CFZ exhibited increased CFZ minimum inhibitory concentrations (MICs) that exceeded MIC increases of BDQ-exposed progeny strains. Notably, and mutations accounted for 83% and 17% of BDQ-induced spontaneous gene mutations, respectively, and 86% and 14% of CFZ-induced spontaneous gene mutations, respectively. Analyses of predicted mutation-induced changes in amino acid sequences and structures of MmpR and PepQ mutants revealed several point mutations affected sequence conversation and functionality as an underlying mechanism for observed acquired BDQ/CFZ resistance. Moreover, our results revealed differences in patterns of BDQ- and CFZ-induced acquired spontaneous mutations that may enhance our understanding of MTB BDQ/CFZ-resistance mechanisms. IMPORTANCE This study of MTB drug resistance mechanisms revealed patterns of spontaneous MTB mutations associated with acquired BDQ and CFZ resistance that arose after clinical MTB isolates were cultured with BDQ or CFZ. Results of protein sequence and structural analyses provided insights into potential mechanisms underlying associations between MTB gene mutations and DR phenotypes. Taken together, these results revealed differences in acquired BDQ and CFZ resistance mechanisms as a new perspective that may enhance our understanding of BDQ/CFZ resistance mechanisms and facilitate the development of new methods for detecting MTB drug resistance genes.
2022年世界卫生组织指南建议使用两种核心抗结核药物——贝达喹啉（BDQ）和氯法齐明（CFZ）来治疗耐多药结核病（DR-TB）。然而，已经报道了几种赋予BDQ和CFZ耐药性的结核分枝杆菌（MTB）基因突变，这些突变主要源于尚未得到全面表征的散发性突变。在此，我们将从药物敏感（DS）、耐多药（MDR）和广泛耐药（XDR）结核病患者中收集的MTB临床分离株分别用BDQ或CFZ进行培养，以产生对这些药物耐药的子代菌株。暴露于CFZ的子代菌株显示出CFZ最低抑菌浓度（MIC）增加，且超过了暴露于BDQ的子代菌株的MIC增加幅度。值得注意的是， 突变分别占BDQ诱导的自发基因突变的83%和17%，以及CFZ诱导的自发基因突变的86%和14%。对MmpR和PepQ突变体的氨基酸序列和结构中预测的突变诱导变化的分析揭示了几个影响序列保守性和功能的点突变，这是观察到的获得性BDQ/CFZ耐药的潜在机制。此外，我们的结果揭示了BDQ和CFZ诱导的获得性自发突变模式的差异，这可能会增进我们对MTB的BDQ/CFZ耐药机制的理解。重要性本研究对MTB耐药机制进行了研究，揭示了临床MTB分离株用BDQ或CFZ培养后出现的与获得性BDQ和CFZ耐药相关的MTB自发突变模式。蛋白质序列和结构分析结果为MTB基因突变与DR表型之间关联的潜在机制提供了见解。综上所述，这些结果揭示了获得性BDQ和CFZ耐药机制的差异，这是一个新的视角，可能会增进我们对BDQ/CFZ耐药机制的理解，并促进检测MTB耐药基因新方法的开发。
