National Clinical Research Center for Infectious Diseases, Guangdong Provincial Clinical Research Center for Tuberculosis, Shenzhen Third People's Hospital, Southern University of Science and Technology, Shenzhen, China.
Department of Traditional Chinese Medicine, The Baoan People's Hospital of Shenzhen, Shenzhen University, Shenzhen, China.
Front Cell Infect Microbiol. 2022 May 27;12:807095. doi: 10.3389/fcimb.2022.807095. eCollection 2022.
Bedaquiline (BDQ), a new antitubercular agent, has been used to treat drug-resistant tuberculosis (TB). Although mutations in , , and confer major resistance to BDQ, the mechanisms of resistance to BDQ and in clinical settings have not been fully elucidated. We selected BDQ-resistant mutants from 7H10 agar plates containing 0.5 mg/L BDQ (the critical concentration) and identified mutations associated with BDQ resistance through whole genome sequencing and Sanger sequencing. A total of 1,025 mutants were resistant to BDQ. We randomly selected 168 mutants for further analysis and discovered that 157/168 BDQ-resistant mutants harbored mutations in , which encodes a transcriptional regulator that represses the expression of the efflux pump, MmpS5-MmpL5. Moreover, we found two mutations with high frequency in at nucleotide positions 286-287 (CG286-287 insertion; accounting for 26.8% [45/168]) and 198-199 (G198, G199 insertion, and G198 deletion; accounting for 14.3% [24/168]). The other mutations were dispersed covering the entire gene. Moreover, we found that one new gene, , harbors a G572 insertion; this mutation has a high prevalence (85.7%; 144/168) in the isolated mutants, and the minimum inhibitory concentration (MIC) assay demonstrated that it is closely associated with BDQ resistance. In summary, we characterized 168/1,025 mutants resistant to BDQ and found that mutations in confer the primary mechanism of BDQ resistance. Moreover, we identified a new gene () involved in BDQ resistance. Our study offers new insights and valuable information that will contribute to rapid identification of BDQ-resistant isolates in clinical settings.
贝达喹啉（BDQ）是一种新的抗结核药物，已用于治疗耐药结核病（TB）。尽管 、 和 中的突变赋予了 BDQ 的主要耐药性，但 BDQ 耐药性和在临床环境中的机制尚未完全阐明。我们从含有 0.5mg/L BDQ（临界浓度）的 7H10 琼脂平板中选择 BDQ 耐药突变体，并通过全基因组测序和 Sanger 测序鉴定与 BDQ 耐药相关的突变。共有 1025 个突变体对 BDQ 耐药。我们随机选择了 168 个突变体进行进一步分析，发现 157/168 个 BDQ 耐药突变体携带编码转录调节剂的 基因突变，该转录调节剂抑制外排泵 MmpS5-MmpL5 的表达。此外，我们在核苷酸位置 286-287（CG286-287 插入；占 26.8%[45/168]）和 198-199（G198、G199 插入和 G198 缺失；占 14.3%[24/168]）发现了两个高频突变。其他突变则分散在整个 基因中。此外，我们发现一个新基因 ，其中包含一个 G572 插入；该突变在分离的突变体中普遍存在（85.7%[144/168]），最小抑菌浓度（MIC）测定表明它与 BDQ 耐药性密切相关。总之，我们对 168/1025 个 BDQ 耐药突变体进行了特征描述，发现 中的突变赋予了 BDQ 耐药的主要机制。此外，我们鉴定了一个新的与 BDQ 耐药相关的基因（）。我们的研究提供了新的见解和有价值的信息，有助于在临床环境中快速鉴定 BDQ 耐药分离株。
