Liu Zhengwei, Pan Aizhen, Wu BeiBei, Zhou Lin, He Haibo, Meng Qiong, Chen Songhua, Pang Yu, Wang Xiaomeng
The Institute of TB Control, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China.
National Clinical Laboratory on Tuberculosis, Beijing Key laboratory for Drug-resistant Tuberculosis Research, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China.
Trop Med Int Health. 2017 Oct;22(10):1328-1333. doi: 10.1111/tmi.12934. Epub 2017 Sep 18.
The poor detection rate of multidrug-resistant tuberculosis (MDR-TB) highlights the urgent need to explore new case finding model to improve the detection of MDR-TB in China. The aim of this study was to evaluate the feasibility of a new model that combines molecular diagnostics and sputum transportation for early detection of patients with MDR-TB in Zhejiang.
From May 2014 to January 2015, TB suspects were continuously enrolled at six county-level designated TB hospitals in Zhejiang. Each patient gave three sputum samples, which were submitted to laboratory for smear microscopy, solid culture and GeneXpert. The specimens from rifampin (RIF)-resistant cases detected by GeneXpert, and positive cultures were transported from county-level to prefecture-level laboratories for line probe analysis (LPA) and drug susceptibility testing (DST). The performance and interval of MDR-TB detection of the new model were compared with those of conventional model.
A total of 3151 sputum specimens were collected from TB suspects. The sensitivity of GeneXpert for detecting culture-positive cases was 92.7% (405/437), and its specificity was 91.3% (2428/2659). Of 16 RIF-resistant cases detected by DST, GeneXpert could correctly identify 15 cases, yielding a sensitivity of 93.8% (15/16). The specificity of GeneXpert for detecting RIF susceptibility was 100.0% (383/383). The average interval to diagnosis of the conventional DST model was 56.5 days, ranging from 43 to 71 days, which was significantly longer than that of GeneXpert plus LPA (22.2 days, P < 0.01).
Our data demonstrate that the combination of improved molecular TB tests and sputum transportation could significantly shorten the time required for detection of MDR-TB, which will bring benefits for preventing an epidemic of MDR-TB in this high-prevalence setting.
耐多药结核病（MDR-TB）的低检出率凸显了在中国探索新的病例发现模式以提高MDR-TB检出率的迫切需求。本研究的目的是评估一种将分子诊断与痰液运送相结合的新模式在浙江省早期发现MDR-TB患者的可行性。
2014年5月至2015年1月，在浙江省6家县级结核病定点医院连续纳入结核病疑似患者。每位患者提供3份痰标本，送至实验室进行涂片镜检、固体培养和GeneXpert检测。对GeneXpert检测出的利福平（RIF）耐药病例的标本以及阳性培养物，从县级实验室运送至地级实验室进行线性探针分析（LPA）和药敏试验（DST）。将新模式的MDR-TB检测性能和间隔时间与传统模式进行比较。
共收集了3151份结核病疑似患者的痰标本。GeneXpert检测培养阳性病例的敏感性为92.7%（405/437），特异性为91.3%（2428/2659）。在DST检测出的16例RIF耐药病例中，GeneXpert能正确识别15例，敏感性为93.8%（15/16）。GeneXpert检测RIF敏感性的特异性为100.0%（383/383）。传统DST模式的平均诊断间隔时间为56.5天，范围为43至71天，显著长于GeneXpert加LPA模式（22.2天，P<0.01）。
我们的数据表明，改进的分子结核病检测与痰液运送相结合可显著缩短检测MDR-TB所需的时间，这将有助于在这一高流行地区预防MDR-TB的流行。
