2005年和2015年结核分枝杆菌乙胺丁醇耐药水平的变化

目的 探讨2005年和2015年结核分枝杆菌对乙胺丁醇(ethambutol,EMB)耐药水平和突变位点的变化情况以及不同突变类型与EMB耐药水平的关系。方法 选取63株2005年、76株2015年的临床分离的耐多药结核分枝杆菌(MDR-TB)为研究对象,采用微孔板阿尔玛蓝显色法(micro plate alamar blue assay, MABA)检测菌株对乙胺丁醇的最小抑菌浓度(minimum inhibitory concentration, MIC)。然后提取核酸并扩增embB基因全序列,对扩增产物进行测序并分析其突变位点。结果 2005年和2015年MDR对EMB的耐药率无统计学差异(χ²=0.105,P=0.745),embB突变类型变化也无明显差别(χ²=9.410,P=0.124)。2005年选取的菌株中,对EMB耐药的有57株,耐药率为90.48%。2015年选取的菌株中对EMB耐药的有71株,耐药率为93.42%。139株MDR中发现embB基因序列上有9个不同位点突变形式,embB突变型合计99株,占所有MDR的71.22%,野生型40株,占所有MDR的28.78%。突变型对EMB的耐药率为99%,野生型对EMB耐药率为75%。结论 embB基因和embB306基因对检测EMB耐药有一定的参考价值。

Change of the ethambutol resistance of Mycobacterium tuberculosis in 2005 and 2015

To investigate the relationship between the levels of resistance to ethambutol (EMB) and mutation sites in Mycobacterium tuberculosis in 2005 and 2015 and the relationship of different mutation types and EMB resistance, 63 clinically isolated M. tuberculosis (MDR-TB) in 2005 and 76 clinically isolated MDR-TB in 2015 were included in this study. The minimal inhibitory concentration (MIC) of EMB against strains was detected by microplate Alamar blue staining method. Then the nucleic acid were extacted and the entire sequence of the embB gene was amplified. The embB gene sequence and the mutation site were analyzed comparing with the sequence of the H37Rv standard strain. As results, 57strains selected in 2005, were resistant to EMB with resistance rate of 90.48%. Among the strains selected in 2015, 71 strains were resistant to EMB with resistance rate of 93.42%. Among the 139 strains of MDR, 9 different site mutations in the embB gene sequence, 99 strains (71.22%) of embB mutations in all MDR, and 40 strains (28.78%) of wild typein all MDR were found. Mutant resistance to EMB was 99%, and wild-type resistance to EMB was 75%. The results showed that there was no statistical difference in MDR resistance to EMB between 2005 and 2015, and there was no significant difference in the change of embB mutation type. Certain reference value of EmbB gene and embB306 gene for EMB resistance was confirmed.