Clinical Performances of Pure TB-Lamp Kit for <i>M. tuberculosis</i>Complex Detection in Sputum Samples

Tuberculosis represents a main concern for public health worldwide. In poor countries, the most prevalent method for bacteriological confirmation re- mains Smear Sputum Microscopy (SSM). This study objective was to assess clinical performances of Loop Mediated Isothermal Amplification for TB detection (Lamp-TB). Sputum of patients presenting symptoms consistent with tuberculosis were collected according to the National Tuberculosis Control Programme guidelines in Centre Antituberculeux de Yopougon. SSM after Ziehl-Neelsen staining and TB-Lamp were blindly performed with spot sputum specimen. Samples, transported at Institut Pasteur de Cote d’Ivoire were decontaminated according to N-acetyl-L-cystein (NALC) method. In Mycobacteria Growth Indicator Tube (MGIT), 500 μl of pellet were inoculated and incubated in MGIT 960 instrument. MPT64 antigen was detected on positive culture. Of 500 patients enrolled, 469 were included. Clinical isolates of M. tuberculosis Complex were detected for 157 (33.5%). Comparatively to culture, Sensitivity and Specificity of SSM were 86% (95% Confidence interval (CI): 81% - 91%) 96% (95%IC: 94% - 98%) respectively. TB-Lamp Sensitivity was 92% (95%CI: 88% - 96%), and Specificity 94% (95%CI: 91% - 97%). Positive Predictive Value of SSM and TB-Lamp was 91.8% and 88.8% respectively. Negative Predictive Value of TB-Lamp assay was 95.7% whereas this of SSM was 93.3%. Positive Likelihood Ratio was 15.3 for TB-Lamp and 21.5 for SSM 21.5 whereas negative Likelihood of TB-Lamp was lower than SSM. Active tuberculosis was detected in162/469 (34.5%) with TB-Lamp and 147 (31.3%) with SSM. TB-Lamp assay performances estimated from sputum samples may improve detection of active TB cases in routine.

低收入国家常规条件下抗酸杆菌痰涂片标准记录方法的评价

背景:贝宁、马拉维、尼加拉瓜和塞内加尔的实验室开展的结核菌痰涂片检查。方法:通过实验室登记进行计算机分析确定工作量、连续痰涂片的检出率及受检人群的人口分布特征结果:42个实验室的60000多个受检查者的资料显示,每个国家每天涂片检测的数量一般为4—19(平均6)。发现一例结核病人平均检查可疑者痰涂片21个(8—50)。所有至少一次阳性结果的病例中,87％的病例在第一次检测中就呈阳性结果。病例人群分布的不同在国家和性别之间变化很大。在42个实验室中的35个实验室里,男性病例的检出率要高于女性。随着年龄的增长,女性要比男性更多数量的可疑者检查方能确诊为一个病例。结论:该研究证实抗酸杆菌涂片结果标准化记录系统具有很好的用途,它能为规程实施和了解受检人群的分布特征方面提供必要的信息。

荧光显微术与萋-尼氏染色技术在检查痰抗酸杆菌方面的比较

背景:塞内加尔达喀尔国家结核病参比实验室。目的:比较荧光显微镜和明视野显微镜检查抗酸杆菌的结果。方法:1996年1月至1998年6月期间2630份痰标本被同时制备2种涂片,在1000倍物镜下分别进行萋-尼氏染色和荧光显微术检查,并应用这两种方法同时检查一例标本的68张涂片来确定判断一张涂片为阴性所需的检查时间。结果:诊断和随访检查时两者的符合率分别为96.9％和92.3％。当标本中每100个视野至少10条菌时,两者的检出率相似,但当标本中每100个视野少于10条菌时,荧光显微术的检出率较高。在同倍物镜下,荧光显微术判断一张涂片为阴性所需的检查时间平均为3分34秒,而萋-尼氏染色技术需7分44秒。结论:两者的检查结果非常相似。对于含菌量少的病例,荧光显微镜似比明视野显微镜的检出率更高,而且所需检查时间少一半多。