Department of Pharmacology, Beijing Tuberculosis and Thoracic Tumor Research Institute, and Beijing Chest Hospital, Capital Medical University, Beijing, China.
Curr Microbiol. 2022 May 26;79(7):205. doi: 10.1007/s00284-022-02881-x.
Novel anti-tuberculosis drug macozinone (MCZ) is identified as a drug candidate and is currently under clinical development for the treatment of tuberculosis. However, the mutations conferring resistance to MCZ remain inadequately characterized. In this study we investigated resistant mutations to the MCZ through de novo resistance selection in vitro. This was accomplished by passing the Mycobacterium tuberculosis H37Rv on solid agar plates, which were infused with the antibiotic. Through whole genome sequencing and targeted PCR genomic resistance conferring SNPs were catalogued, and the resistant phenotype was analyzed by MABA test. Of MCZ-resistant clones obtained in vitro the mutation of C387S in dprE1 is only observed in high-level resistant clones (MIC > 500 ng/mL) indicating that C387S mutation is directly related to high-level MCZ-resistance. In addition, high-level resistance to MCZ can occur in clone grew on agar plates infused with low concentration MCZ, which means low concentration MCZ induction can produce high-level drug-resistance and it is easy to produce high-level MCZ-resistance. We also found two new mutations (G61A and G248A) in dprE1 for the first time. The MIC of other clones except the clones carrying the C387S mutation was at the same level (20 ng/mL > MIC > 2 ng/mL). Of low-level resistant clones other gene mutations involved in drug efflux or membrane permeability were found (pepQ, Rv0678, arsC, etc.), with highest mutation frequency in Rv0678 (50/64, 78.12%). It suggests that there may be new mechanisms independent of dprE1 mutations.
新型抗结核药物马卡佐因（MCZ）被鉴定为一种候选药物，目前正在进行临床试验，用于治疗结核病。然而，导致对 MCZ 耐药的突变仍未得到充分描述。在这项研究中，我们通过体外从头耐药选择研究了对 MCZ 的耐药突变。这是通过将结核分枝杆菌 H37Rv 传代到固体琼脂平板上，平板中注入抗生素来实现的。通过全基因组测序和靶向 PCR 基因组耐药相关 SNP 进行编目，并通过 MABA 试验分析耐药表型。在体外获得的 MCZ 耐药克隆中，仅在高水平耐药克隆（MIC>500ng/mL）中观察到 dprE1 中的 C387S 突变，这表明 C387S 突变与高水平 MCZ 耐药直接相关。此外，在琼脂平板上注入低浓度 MCZ 生长的克隆中也会出现高水平的 MCZ 耐药，这意味着低浓度 MCZ 诱导可产生高水平耐药，且易产生高水平 MCZ 耐药。我们还首次在 dprE1 中发现了两个新突变（G61A 和 G248A）。除携带 C387S 突变的克隆外，其他克隆的 MIC 水平相同（20ng/mL> MIC>2ng/mL）。在低水平耐药克隆中，还发现了其他涉及药物外排或膜通透性的基因突变（pepQ、Rv0678、arsC 等），其中 Rv0678 的突变频率最高（50/64，78.12%）。这表明可能存在独立于 dprE1 突变的新机制。
