Ou Xichao, Song Yuanyuan, Zhao Bing, Li Qiang, Xia Hui, Zhou Yang, Pang Yu, Wang Shengfen, Zhang Zhijian, Cheng Shiming, Liu Changting, Zhao YanLin
Chinese Center for Disease Control and Prevention, Beijing, China.
Chinese PLA General Hospital, Beijing, China.
Tuberculosis (Edinb). 2014 Jul;94(4):428-33. doi: 10.1016/j.tube.2014.04.006. Epub 2014 May 5.
Cross-Priming Amplification (CPA) has been shown to rapidly and effectively detect Mycobacterium tuberculosis (MTB) in sputum samples under isothermal conditions. However, no performance data exist from peripheral-level tuberculosis (TB) clinics in tuberculosis-endemic countries. We conducted a clinical trial at four county-level TB clinics in China to evaluate the effectiveness of the CPA assay. TB suspects were continuously enrolled by a clinician at each clinic. Following informed consent, each patient provided two sputum specimens (spot and morning sputum). Sputum samples were tested by smear microscopy, solid culture and CPA. The National TB reference laboratory (NTRL) collected all culture positive strains and performed 16S-23S rDNA internal transcribed spacer (ITS) sequence analysis for strain identification. Solid culture was used as the gold standard to evaluate the effectiveness of CPA in detecting MTB. A total of 2200 TB-suspected patients were enrolled at the four county-level TB clinics. Compared to solid culture, the sensitivity and specificity of the CPA test for MTB detection within this group was 84.1% (95%CI, 79.5-88.6) and 97.8% (95%CI, 97.1-98.5), respectively, and the sensitivity in smear-negative cases was 59.8% (95%CI, 49.8-69.8). The test failure rate of CPA was 0.8% (32/3918), significantly lower than the 1.7% (106/6138) culture contamination rate.
交叉引物扩增（CPA）已被证明可在等温条件下快速有效地检测痰标本中的结核分枝杆菌（MTB）。然而，结核病流行国家的基层结核病诊所尚无相关性能数据。我们在中国的四家县级结核病诊所进行了一项临床试验，以评估CPA检测法的有效性。每家诊所的临床医生持续招募结核病疑似患者。在获得知情同意后，每位患者提供两份痰标本（即时痰和晨痰）。痰标本通过涂片显微镜检查、固体培养和CPA进行检测。国家结核病参比实验室（NTRL）收集所有培养阳性菌株，并进行16S-23S rDNA内部转录间隔区（ITS）序列分析以进行菌株鉴定。固体培养用作评估CPA检测MTB有效性的金标准。四家县级结核病诊所共招募了2200名结核病疑似患者。与固体培养相比，该组中CPA检测MTB的灵敏度和特异性分别为84.1%（95%CI，79.5-88.6）和97.8%（95%CI，97.1-98.5），涂片阴性病例中的灵敏度为59.8%（95%CI，49.8-69.8）。CPA的检测失败率为0.8%（32/3918），显著低于1.7%（106/6138）的培养污染率。
