GeneXpert MTB/RIF试验与4种结核分枝杆菌检测方法的比较

Comparison of GeneXpert MTB/RIF assay with four mycobacterium tuberculosis (MTB) detection methods

目的:比较GeneXpert MTB/RIF试验(Xpert试验)与4种结核分枝杆菌检测方法,探讨Xpert试验在肺结核快速诊断中的应用价值。方法:收集2015-08—2016-02武汉市肺科医院各病区送检的同一患者的3份痰标本共计536例,同时进行荧光抗酸染色涂片、结核分枝杆菌核酸扩增荧光检测(TB-DNA PCR)、Xpert试验、罗氏固体培养及MGIT960液体培养检测,比较5种方法在诊断结核病中的敏感度与特异度。结果:荧光抗酸染色涂片、TB-DNA PCR、Xpert试验、罗氏固体培养及MGIT960液体培养检测结核分枝杆菌的敏感度分别为42.97%、57.57%、62.43%、54.59%和62.43%;特异度分别为95.27%、99.21%、98.42%、88.97%及88.19%。在涂片阳性肺结核中,Xpert检出率为99.37%(158/159),MGIT960培养检出率为98.11%(156/159);在涂片阴性肺结核中,Xpert检出率为34.60%(73/211),MGIT960培养检出率为35.55%(75/211)。在220例Xpert检测与培养均阳性的标本中,两者均耐药为32例,均敏感为179例,Xpert利福平耐药而比例法敏感为8例,Xpert利福平敏感而比例法耐药为1例。2种方法检测利福平耐药具有高的一致性(Kappa值0.85)。结论:Xpert试验在肺结核诊断中具有与金标准液体培养一致的敏感性,同时快速筛查利福平耐药结核,对控制耐药结核的传播具有重要的临床价值,值得在临床推广应用。

Objective:To explore rapid diagnosis of GeneXpert MTB/RIF assay (Xpert assay)on tuberculo-sis by comparing Xpert with four mycobacterium tuberculosis (MTB)detection methods.Method:From August 2015to February 2016,536patients were included in the study,3sputum specimens from every patient were col-lected for smear fluorescent staining,TB-DNA PCR,Xpert assay,L-J solid culture and MGIT960liquid culture. Sensitivity and specificity of 5detection methods were compared.Result:Sensitivities of smear fluorescent stai-ning,TB-DNA PCR,Xpert assay,L-J solid culture and MGIT960liquid culture were 42.97%,57.57%,62.43%,54.59%and 62.43%,respectively.Specificities of five methods were 95.27%,99.21%,98.42%,88.97%and 88.19%.Among the smear-positive patients,the detection rates of Xpert and MGIT960liquid cul-ture were 99.37% (158/159 ), 98.11% (156/159)respectively ; among the smear-negative patients,the detec-tion rates of Xpert and MGIT960liquid culture was 34.60% (73/211 ), 35.55% (75/211)respectively.MTB was detected by Xpert and MGIT960liquid culture from 220patients,in which 32strains were resistant to rifampicin by two methods,179strains were sensitive to rifampicin by two methods,8strains were resistant by Xpert,but sensitive by the proportion method,1strain was sensitive by Xpert,but resistant by the proportion method. The two methods had excellent consistency (Kappa value 0.85)Conclusion:Xpert assay has similar sensitivity with the gold standard MGIT960liquid culture in diagnosis of tuberculosis and can rapidly screen resistance of rif-ampicin.The method is worth expanding and applying in clinical practice.