粪便Gene Xpert MTB/RIF检测对HIV阴性肠结核的早期快速诊断价值

The value of Gene Xpert MTB/RIF detection in feces in the early and rapid diagnosis of HIV negative intestinal tuberculosis

目的:评价Gene Xpert结核分枝杆菌/利福平(MTB/RIF,简称“Xpert”)在人类免疫缺陷病毒(HIV)阴性肠结核患者早期快速诊断中的价值。方法:选取2018年1月至2019年6月在山东省胸科医院、北京胸科医院、苏州市第五人民医院3家医院就诊的254例HIV阴性疑似肠结核患者。采集所有患者的粪便标本,每份标本分别进行Xpert检测、涂片查抗酸杆菌、BACTEC MGIT 960(简称“MGIT 960”)分枝杆菌培养。以临床诊断为标准,评价Xpert检测粪便标本的敏感度和特异度,若培养结果为阳性,则对菌株进行利福平药物敏感性检测,并对Xpert检测结果与MGIT 960药敏检测结果一致性进行分析。结果:254例患者中139例(54.7%)临床诊断为肠结核,115例(45.3%)临床诊断为非肠结核。139例肠结核患者中,60例(43.2%)MGIT 960分枝杆菌培养阳性;79例(56.8%)按临床表现、肠镜检查结果、抗结核治疗效果等临床诊断为肠结核。以临床诊断为标准,Xpert检测粪便标本的敏感度[60.4%(84/139)]优于抗酸杆菌涂片敏感度[13.2%(17/139)],两者敏感度比较有统计学差异(P<0.001),Xpert检测特异度为100.0%(84/84);MGIT 960分枝杆菌培养敏感度为43.2%(60/139),与Xpert检测比较有统计学差异(P=0.004)。结核分枝杆菌(MTB)培养阳性患者中,Xpert检测的敏感度为98.3%(59/60)。在涂片和培养均为阴性的肠结核患者中,Xpert检测的阳性率为31.6%(25/79)。结论:Xpert检测粪便标本中MTB较抗酸杆菌涂片和MGIT 960分枝杆菌培养敏感度更高,并且可以同时检测利福平耐药性,为早期快速诊断肠结核提供细菌学依据。

Objective:To evaluate the value of Gene Xpert MTB/RIF detection in feces for the early and rapid diagnosis of patients with HIV negative intestinal tuberculosis.Methods:Totally,254 HIV-negative patients with suspected intestinal tuberculosis admitted in three tuberculosis hospitals,Shandong Provincial Chest Hospital,Beijing Chest Hospital,and Suzhou Fifth People’s Hospital from January 2018 to June 2019 were included.The feces(stool)samples of all patients were collected,and each sample was analyzed by Xpert detection,smear acid fast bacilli examination,and BACTEC MGIT 960(MGIT 960)mycobacterium culture.The sensitivity and specificity of stool samples detected by Xpert were evaluated using the clinical diagnosis as a standard.Rifampicin drug sensitivity test was carried out for all positive strains.The consistency between Xpert test results and MGIT 960 drug sensitivity test results was compared.Results:Among the 254 patients,139(54.7%)were diagnosed as intestinal tuberculosis and 115(45.3%)as non-intestinal tuberculosis.Of the 139 patients with intestinal tuberculosis,60(43.2%)were positive for MGIT 960 mycobacterium culture,79(56.8%)were diagnosed as intestinal tuberculosis according to the clinical manifestations,enteroscopy results and therapeutic effects of antituberculosis.With the standard diagnosis based on the clinical diagnosis,the sensitivity of Xpert[60.4%(84/139)],was higher than that of acid fast smear[13.2%(17/139)].The sensitivity difference between the above two methods was of statistical significance(P<0.001).The specificity of Xpert was 100%.There was a statistical significant difference in the sensitivity between MGIT 960 and Xpert detection[43.2%(60/139)vs 98.3%(59/60),P=0.004].The sensitivity of Xpert was.The positive rate of Xpert results was 31.6%(25/79)in patients who had negative acid fast smear and MGIT 960 mycobacterium culture results but were clinically diagnosed as intestinal tuberculosis.Conclusions:The detection of Mycobacterium tuberculosis in fecal samples by Xpert is more sensitive than acid fast smear and MGIT 960 mycobacterium culture,and it can detect rifampicin resistance at the same time,providing bacteriological basis for early rapid diagnosis of intestinal tuberculosis.