He Jing, Gao Yamin, Wang Jingyun, Hameed H M Adnan, Wang Shuai, Fang Cuiting, Tian Xirong, Zhang Jingran, Han Xingli, Ju Yanan, Tan Yaoju, Ma Junying, Ju Jianhua, Hu Jinxing, Liu Jianxiong, Zhang Tianyu
Institute of Physical Science and Information Technology Anhui University Hefei China.
State Key Laboratory of Respiratory Disease Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China.
mLife. 2024 Sep 30;3(3):459-470. doi: 10.1002/mlf2.12139. eCollection 2024 Sep.
Treatment of (Mab) infections is very challenging due to its intrinsic resistance to most available drugs. Therefore, it is crucial to discover novel anti-Mab drugs. In this study, we explored an intrinsic resistance mechanism through which Mab resists echinomycin (ECH). ECH showed activity against Mab at a minimum inhibitory concentration (MIC) of 2 µg/ml. A ΔembC strain in which the gene was knocked out showed hypersensitivity to ECH (MIC: 0.0078-0.0156 µg/ml). The MICs of ECH-resistant strains screened with reference to ΔembC ranged from 0.25 to 1 µg/ml. Mutations in EmbB, including D306A, D306N, R350G, V555I, and G581S, increased the Mab's resistance to ECH when overexpressed in ΔembC individually (MIC: 0.25-0.5 µg/ml). These EmbB mutants, edited using the CRISPR/Cpf1 system, showed heightened resistance to ECH (MIC: 0.25-0.5 µg/ml). The permeability of these Mab strains with edited genes and overexpression was reduced, as evidenced by an ethidium bromide accumulation assay, but it remained significantly higher than that of the parent Mab. In summary, our study demonstrates that ECH exerts potent anti-Mab activity and confirms that EmbB and EmbC are implicated in Mab's sensitivity to ECH. Mutation in EmbB may partially compensate for a loss of EmbC function.
由于结核分枝杆菌（Mab）对大多数现有药物具有内在抗性，因此其感染的治疗极具挑战性。因此，发现新型抗Mab药物至关重要。在本研究中，我们探索了Mab对棘霉素（ECH）产生抗性的一种内在机制。ECH对Mab的最低抑菌浓度（MIC）为2μg/ml时表现出活性。敲除embC基因的ΔembC菌株对ECH表现出超敏性（MIC：0.0078 - 0.0156μg/ml）。参照ΔembC筛选出的ECH抗性菌株的MIC范围为0.25至1μg/ml。EmbB中的突变，包括D306A、D306N、R350G、V555I和G581S，在ΔembC中单独过表达时会增加Mab对ECH的抗性（MIC：0.25 - 0.5μg/ml）。使用CRISPR/Cpf1系统编辑的这些EmbB突变体对ECH表现出更高的抗性（MIC：0.25 - 0.5μg/ml）。溴化乙锭积累试验表明，这些基因编辑和过表达的Mab菌株的通透性降低，但仍显著高于亲本Mab。总之，我们的研究表明ECH具有强大的抗Mab活性，并证实EmbB和EmbC与Mab对ECH的敏感性有关。EmbB中的突变可能部分补偿EmbC功能的丧失。
