embB基因突变与乙胺丁醇药敏表型及耐多药关系的研究

Assosciation between embB mutation and drug resistance and MDR in Mycobacterium tuberculosis for ethambutol

目的研究结核分枝杆菌(Mycobacterium tuberculosis,MTB)emb B306位点及其他突变位点与乙胺丁醇(ethambutol,EMB)的耐药表型及耐多药(multidrug resistant,MDR)的关系;分析emb B基因突变与EMB药敏表型及MDR的关系。方法对临床分离的MTB采用BD MGIT 960 SIRE试剂比例法进行药敏试验,取48株EMB耐药、46株EMB敏感但耐其他药及7株四药均敏感MTB提取核酸并扩增emb B基因全序列,对扩增产物进行测序分析emb B基因序列,与H37Rv标准株序列比对,分析emb B基因各突变位点、形式及频率。结果 101株MTB发现emb B基因序列上有17个不同位点突变形式。53株MTB在emb B基因序列上发生突变,其中46株为EMB耐药,7株为EMB敏感;emb B基因野生型的MTB有48株,其中2株为EMB耐药,46株为EMB敏感;emb B突变型与emb B野生型的MTB之间EMB耐药率有显著性差异(c2=68.95,P<0.01)。101株MTB中MDR有51株,其中有42株发生emb B突变,9株为emb B基因野生型,emb B基因突变率在MDR和非MDR之间有显著性差异(c2=36.9,P<0.01)。结论 emb B306位点与EMB耐药及MDR中度相关,emb B基因突变与EMB耐药及耐多药结核菌(multidrug resistant-Mycobacterium tuberculosis,MDR-TB)高度相关,emb B基因突变可作为MDR-TB的检测分子标记物,指导临床用药。

Objective To determine Mycobacterium tuberculosis（MTB） emb B306 and other loci molecular mutations and their association with ethambutol（EMB） resistance phenotype and multidrug resistant（MDR）; to determine molecular mutation in emb B gene and its association with EMB resistance phenotype and MDR. Methods The drug sensitivity test was carried out using ratio method by BD 960 MGIT SIRE reagent for clinical isolates of MTB, the DNA of 48 EMB resistance, 46 EMB sensitive but resistance to other drugs and 7 sensitive to four drugs of MTB were extracted and amplified emb B gene sequence. The amplified products were then sequenced and analyzed the emb B gene sequence of each MTB, compared with H37 Rv standard strain in Genbank, the mutation sites, the form and the frequency of emb B gene were analyzed.Results 17 different mutant forms were found in 101 strains of MTB emb B gene. 53 strains of MTB mutated in the emb B gene, 46 strains of which were EMB resistant, 7 were EMB sensitive; 48 strains of MTB were wild type in the emb B gene, 2 strains of which were EMB resistant, 46 were EMB sensitive. There were significant differences in the drug resistance positive rates of EMB between emb B mutation and emb B wild type（c2=68.95,P〈0.01）. There were 51 strains MDR in 101 MTB, including 42 strains of emb B mutation, and 9 strains of emb B wildtype, the mutation rate of emb B gene was significantly different between MDR and non-MDR（c2=36.9, P〈0.01）. Conclusion emb B 306 mutation is moderately related to EMB resistance in MTB, mutation of emb B gene is highly associated with EMB resistance and MDR-TB, the emb B gene can be used as a marker for the detection of MDR-TB, which could be used guideline for clinical drug use.