RRDR突变特征及Xpert单独或联合检测对结核病的诊断效能

Analysis of RRDR mutation characteristics and Xpert single or combined detection in the diagnosis of tuberculosis

目的阐明Xpert阳性患者利福平耐药决定区(RRDR)突变特征,并探讨Xpert单独或联合检测对结核病的诊断效能。方法选取2019年12月-2022年3月遂宁市中心医院门诊及住院部收治的疑似结核病患者1418例为研究对象,1418例患者均送检标本进行Xpert检测,对同时进行抗酸涂片、结核培养、Xpert、结核分枝杆菌DNA(DNA)检测的664例可疑结核病患者根据临床最终诊断将其分为结核病组(n=435)和非结核组(n=229)。分析Xpert阳性标本rpoB基因RRDR突变情况及抗酸涂片、结核培养、Xpert、DNA单独或联合检测诊断结核病的灵敏性、特异性、约登指数和受试者工作特征曲线下面积(AUC)。结果1418例患者均送检标本进行Xpert检测,阳性550例,阳性率为38.79%;550例Xpert检测阳性患者中,50例利福平耐药,利福平耐药率为9.09%;rpoB基因RRDR突变以单探针突变为主,单探针突变率最高的为Probe E[60.00%(30/50)],其次为Probe A[16.00%(8/50)]、Probe D[(14.00%(7/50)]、Probe B[6.00%(3/50)],未发现Probe C的突变;检测到2例双探针突变,未发现三探针突变。以临床最终诊断为金标准,Xpert单独检测诊断结核病的灵敏性、特异性、约登指数、AUC分别为82.07%、94.76%、0.77、0.884,高于抗酸涂片、结核培养、DNA单独检测;抗酸涂片+结核培养+Xpert诊断结核病的灵敏性、特异性、约登指数、AUC分别为93.56%、94.76%、0.88、0.942,高于抗酸涂片+结核培养(67.13%、92.58%、0.60、0.799)和抗酸涂片+结核培养+DNA检测(74.48%、91.70%、0.66、0.831),但略低于抗酸涂片+结核培养+Xpert+DNA检测(96.55%、96.94%、0.93、0.967)。结论rpoB基因RRDR突变以Probe E单探针突变为主,未检测到Probe C的突变以及三探针突变。从诊断经济学考虑,抗酸涂片+结核培养+Xpert检测在结核病诊断中具有良好的诊断效能。

Objective To elucidate the mutation characteristics of rifampicin resistance determining region(RRDR)in tuberculosis patients with Xpert positive results,and analyze the diagnostic value of Xpert individual or combined in the diagnosis of tuberculosis.Methods A total of 1418 suspected tuberculosis patients admitted to the outpatient and inpatient departments of the Suining Central Hospital from December 2019 to March 2022 were selected as the research objects.All 1418 patients were submitted for Xpert testing,and 664 suspected tuberculosis patients who underwent acid-fast smear,tuberculosis culture,Xpert,and Mycobacterium tuberculosis DNA(DNA)testing were divided into the tuberculosis group(n=435)and non-tuberculosis group(n=229)according to the final clinical diagnosis.The rpoB gene RRDR mutation of Xpert-positive samples and the sensitivity,specificity,Yoden index and area under curve(AUC)of the receiver operating characteristic of acid-fast smear,tuberculosis culture,Xpert and DNA testing alone or in combination for the diagnosis of tuberculosis were analyzed.Results A total of 1418 patients submitted samples for Xpert detection,and 550 cases were positive,with a positive rate of 38.79%.Among the 550 positive Xpert patients,50 cases were rifampicin-resistant,and the rifampicin resistance rate was 9.09%.For the rpoB gene of RRDR,the mutations were mainly single-point mutations,and the highest single-point mutation rate was Probe E[60.00%(30/50)],followed by Probe A[16.00%(8/50)],Probe D[(14.00%(7/50)]and Probe B[6.00%(3/50)];no mutation of Probe C was found;2 cases of double-point mutation were detected,and no three-point mutation was found.Taking the final clinical diagnosis as the gold standard,the sensitivity,specificity,Youden index,and AUC of Xpert alone in diagnosing tuberculosis were 82.07%,94.76%,0.77,and 0.884,respectively,which were higher than those of acid-fast smear,tuberculosis culture,and DNA testing alone.The sensitivity,specificity,Youden index,and AUC of acid-fast smear+tuberculosis culture+Xpert in diagnosing tuberculosis were 93.56%,94.76%,0.88,and 0.942,respectively,which were higher than those of acid-fast smear+tuberculosis culture(67.13%,92.58%,0.60,0.799)and acid-fast smear+tuberculosis culture+DNA testing(74.48%,91.70%,0.66,0.831),but slightly lower than acid-fast smear+tuberculosis culture+Xpert+DNA testing(96.55%,96.94%,0.93,0.967).Conclusions The rpoB gene of RRDR mutation was dominated by Probe E single-point mutations,and no Probe C mutations and three-point mutations were detected.From the perspective of diagnostic cost,acid-fast smear+tuberculosis culture+Xpert test had good diagnostic efficiency in the diagnosis of tuberculosis.