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目的比较结核分枝杆菌利福平依赖株和耐药株在形态学及分子生物学方面的差异。方法制作利福平浓度梯度培养基,观察利福平依赖株和耐药株结核杆菌在含不同浓度利福平培养基上的菌落生长情况;采用抗酸染色和电镜观察二细菌的形态和超微结构;采用DNA测序技术分析细菌rpoB核心突变区的序列。结果利福平耐药菌株在200μg/ml利福平培养基上不生长,依赖株在700μg/ml药物培养基上生长旺盛。抗酸染色后电镜观察,利福平依赖菌株在含利福平培养基上生长良好,菌体粗大,细胞壁完整;对照培养基上的菌体细小,细胞壁破裂。测序分析二细菌在rpoB核心突变区均发生突变,其中依赖菌株的突变主要发生在531和526位,耐药株5个位点均有突变发生。结论利福平耐药株和依赖株结核分枝杆菌在形态学和超微结构上存在着明显差异,且这种差异可能与rpoB突变位点的不同存在一定相关性。
Objective To compare the morphological and molecular biological differences between Mycobacterium tuberculosis rifampin-dependent strains and drug-resistant strains. Methods The rifampicin concentration gradient culture medium was prepared to observe the growth of the rifampin-dependent strains and the resistant strains Mycobacterium tuberculosis on the rifampin-containing medium with different concentrations. The morphology and ultrastructure of the two bacteria were observed by acid-fast staining and electron microscopy Microstructure. The sequence of bacterial rpoB core mutation was analyzed by DNA sequencing. Results The rifampicin-resistant strains did not grow on 200μg / ml rifampicin medium, and the dependent strains grew vigorously on 700μg / ml drug medium. After acid-fast staining, the rifampicin-dependent strains grew well on rifampin-containing medium, the cells were coarse and the cell wall was intact; the cells on the control medium were small and the cell wall ruptured. Sequence analysis of two bacteria in the rpoB core mutations were mutated, of which strain-dependent mutations occurred mainly in the 531 and 526, resistant strains at five sites have mutations. Conclusion There is a significant difference in morphology and ultrastructure between rifampicin-resistant strains and Mycobacterium tuberculosis strains, and this difference may be related to the difference of rpoB mutation sites.