微孔板法与GeneXpert MTB/RIF技术检测结核分枝杆菌对利福平耐药性的价值

目的探讨微孔板法和GeneXpert MTB/RIF(简称“GeneXpert”)技术检测MTB对利福平(RFP)耐药性的价值。方法收集陕西省结核病防治院2017年收住入院和门诊诊治的疑似结核病患者6893例,按照临床诊断标准确诊为结核病患者6086例,同时使用BACTECMGIT960液体培养(简称“MGIT960法”)和GeneXpert技术检测上述确诊患者的425份临床标本;其中,痰标本217份、肺泡灌洗液标本170份、肺外标本(包括胸腹腔积液、脓液,脑脊液等)38份;排除3例报告错误或无法判读、2例培养结果污染的标本,有效标本份数为420份。对其中GeneXpert技术和MGIT 960液体培养均为阳性的372株临床分离株同时进行微孔板法、GeneXpert技术和MGIT 960耐药性检测,其中痰标本191例、肺泡灌洗液标本158例、肺外标本(包括胸腹腔积液、脓液及脑脊液等)23例,以MGIT960检测结果为标准,分析微孔板法和GeneXpert技术检测结核分枝杆菌对RFP耐药性的诊断价值。结果GeneXpert技术、微孔板法和MGIT960法对RFP耐药性检测总的阳性率分别为18.8%(70/372)、16.7%(62/372)、16.7%(62/372)。以MGIT960法检测结果为标准,微孔板法和GeneXpert法对利福平耐药性检测的敏感度、特异度、符合率、Kappa值分别为91.9%(57/62)、98.4%(305/310)、97.3%(362/372)、0.8,96.8%(60/62)、96.8%(300/310)、96.8%(360/372)、0.8;微孔板法和GeneXpert法对痰液、肺泡灌洗液、肺外标本利福平耐药性检测的敏感度、特异度、符合率、Kappa值分别为96.7%(29/30)、98.1%(158/161)、97.9%(187/191)、0.9,93.3%(28/30)、96.3%(155/161)、95.8%(183/191)、0.9,91.7%(22/24)、98.5%(132/134)、97.5%(154/158)、0.9和100.0%(24/24)、97.0%(130/134)、97.5%(154/158)、0.9,75.0%(6/8)、100.0%(15/15)、91.3%(21/23)、0.8,100.0%(8/8)、100.0%(15/15)、100.0%(23/23)、1.0。结论以MGIT960检测结果为标准,微孔板法和GeneXpert技术对利福平耐药性检测总的阳性率和不同标本对利福平耐药性检测的阳性率均具有较好的一致性。

The value of MicroDST and GeneXpert MTB/RIF test in detecting Mycobacterium tuberculosis resistance to rifampicin

Objective To compare the results of Mycobacterium tuberculosis (MTB) resistance to rifampicin (RFP) by Micropore-plate method (Microdrug sensitivity, MicroDST) and GeneXpert MTB/RIF test. Methods Among the 6893 suspected MTB patients who admitted to or visited Outpatient Department in Shaanxi Provincial Tuberculosis Control and Prevention Hospital, 6086 patients were diagnosed as MTB cases according to the clinical diagnostic criteria. A total of 425 clinical specimens were tested by BACTEC MGIT 960 liquid culture method and GeneXpert method, including 217 sputum specimens, 170 alveolar lavage specimens, and 38 extrapulmonary fluid specimens (such as pleural and peritoneal effusion, pus and cerebrospinal fluid). After excluding 3 specimens that reported errors or could not be interpreted and 2 specimens that were contaminated when cultured, there were 420 valid specimens. Three hundred and seventy-two clinical isolates with positive results by GeneXpert and MGIT 960 method were tested for drug resistance by MicroDST, GeneXpert MTB/RIF and MGIT 960 method, including 191 sputum specimens, 158 alveolar lavage specimens, and 23 extrapulmonary fluid specimens (such as pleural and peritoneal effusion, pus and cerebrospinal fluid). Taking MGIT 960 test as the gold standard, the performance of MicroDST and GeneXpert MTB/RIF in detecting MTB resistance to RFP were compared. Results The overall positive rates of RFP resistance by GeneXpert MTB/RIF, MicroDST and MGIT 960 method were 18.8% (70/372), 16.7% (62/372), and 16.7% (62/372), respectively. Taking MGIT 960 test as the gold standard, the sensitivity, specificity, coincidence rate and Kappa value of RFP resistance test were 91.9% (57/62), 98.4% (305/310), 97.3% (362/372) and 0.8 by MicroDST assay and 96.8% (60/62), 96.8% (300/310), 96.8% (360/372) and 0.8 by GeneXpert MTB/RIF assay. The sensitivity, specificity, coincidence rate and Kappa value using sputum, alveolar lavage and extrapulmonary specimens were 96.7% (29/30), 98.1% (158/161), 97.9% (187/191), 0.9; 93.3% (28/30), 96.3% (155/161), 95.8% (183/191), 0.9; and 91.7% (22/24), 98.5% (132/134), 97.5% (154/158), 0.9 by MicroDST assay and 100.0% (24/24), 97.0% (130/134), 97.5% (154/158), 0.9; 75.0% (6/8), 100.0% (15/15), 91.3% (21/23), 0.8; and 100.0% (8/8), 100.0% (15/15), 100.0% (23/23), 1.0 by GeneXpert MTB/RIF assay, respectively. Conclusion Taking MGIT 960 test as the gold standard, MicroDST and GeneXpert MTB/RIF assay have a good consistency in overall positive detection rate of RFP resistance, as well as in different samples.