embB 306位点作为耐多药结核分枝杆菌分子检测标记初探

目的 研究embB基因306位点(embB 306)突变在耐多药结核分枝杆菌中的分布,探讨以该位点作为耐多药分子检测标记的应用前景.方法 从上海疾病预防控制中心获得其保存的已知耐药表型的结核分枝杆菌291株,使用错配PCR及DNA测序两种方法检测其embB 306位点的突变,分析耐药表型与结核分枝杆菌embB 306位点的突变的相关性.结果 74株耐多药菌株中有38株(51.4%)该位点有突变(X2=93.8,P<0.01),而其他24株多耐药菌株中有9株(37.5%)为embB 306突变株(X2=60.1,P<0.01);41株耐单药菌株中仅有2株(4.9%)存在该位点的突变(X2=6.8,P=0.0093),而152株全敏感菌株中无一存在该位点突变.以embB 306位点作为耐多药结核分枝杆菌(MDR-TB)分子检测标记的特异度达94.9%(206/217).结论 以embB 306作为耐药突变位点,特别是耐多药结核分枝杆菌的分子检测标记,具有一定的灵敏度和较高的特异度,而且检测方法简单易行,可用于耐多药结核分枝杆菌的临床快速检测.

DNA location embB 306 regarded as the molecular marker for drug resistant Mycobacterium tuberculosis

Objective To investigate the prevalence of mutation in the locus 306 of embB gene in multi-drug resistant (MDR) Mycobacterium tuberculosis (TB) and evaluate the prospects for using it as a molecular marker to detect MDR-TB.Methods The 291 strains enrolled in this study were from the reference laboratory of Shanghai municipal centers for disease control and prevention, all of which had been tested for drug susceptibility.Mutation in embB 306 was screened both by amplification refractory mutation system (ARMS) and DNA sequencing.The mutation frequencies of embB 306 in the sample groups varied in drug resistance were statistically analyzed.Results 38(51.4% ) of the 74 MDR-TB were embB 306-mutant (X2 =93.8,P＜0.01).Of the 24 TB resistant to at least two drugs but not MDR, 9(37.5% ) were embB 306 mutant (X2 =60.1 ,P＜0.01 ).But only two(4.9% ) embB 306-mutant strains were found in 41 strains resistant to only one drug (X2 =6.8,P=0.0093).None embB 306-mutant strains were found in 152 pansensitive strains.The specificity of using embB 306 as a molecular marker for detecting multi-drug resistant TB was 94.9% (206/217).Conclusions As a molecular marker for screening drug resistant TB,especially MDR-TB, the gene locus embB 306 shows a relatively high sensitivity and specificity, promising a sound future for its application in clinics to realize fast screening of patients infected with MDR-TB and to provide evidence for appropriate medication.