Division of Infectious Disease, St John's Research Institute, Bangalore, India.
PLoS One. 2011;6(6):e21007. doi: 10.1371/journal.pone.0021007. Epub 2011 Jun 17.
Despite the advent of novel diagnostic techniques, smear microscopy remains as the most practical test available in resource-limited settings for tuberculosis (TB) diagnosis. Due to the low sensitivity of microscopy and the long time required for culture, feasible and accessible rapid diagnostic methods are urgently needed. Loop-mediated Isothermal Amplification (LAMP) is a promising nucleic-acid amplification assay, which could be accessible, cost-effective and more suited for use with unpurified samples.
METHODOLOGY/PRINCIPAL FINDINGS: In the current study, the objective was to assess the efficacy of a LAMP assay for tuberculosis compared with fluorescence smear microscopy as well as Löwenstein-Jensen (LJ) and Mycobacteria Growth Indicator Tube (MGIT) cultures for the diagnosis of pulmonary tuberculosis using sputum samples. Smear microscopy and culture were performed for decontaminated and concentrated sputum from TB suspects and the LAMP was also performed on these specimens. The LAMP and smear microscopy were compared, in series and in parallel, to culture. LAMP and smear microscopy showed sensitivities of 79.5% and 82.1% respectively and specificities of 93.8% and 96.9% respectively, compared to culture. LAMP and smear in series had sensitivity and specificity of 79.5% and 100.0% respectively. LAMP and smear in parallel had sensitivity and specificity of 82.1% and 90.6% respectively.
CONCLUSIONS/SIGNIFICANCE: The overall efficacies of LAMP and fluorescence smear microscopy in the current study were high and broadly similar. LAMP and smear in series had high specificity (100.0%) and can be used as a rule-in test combination. However, the performance of LAMP in smear negative samples was found to be insufficient.
尽管出现了新的诊断技术，但涂片显微镜检查仍然是资源有限环境中用于结核病（TB）诊断的最实用的检查方法。由于显微镜检查的敏感性低，培养所需的时间长，因此迫切需要可行和易于获得的快速诊断方法。环介导等温扩增（LAMP）是一种很有前途的核酸扩增检测方法，它具有可及性、成本效益高的特点，更适合用于未纯化的样本。
方法/主要发现：在本研究中，我们的目的是评估 LAMP 检测在诊断肺结核方面的效果，将其与荧光涂片显微镜检查以及 Löwenstein-Jensen（LJ）和分枝杆菌生长指示管（MGIT）培养法进行比较，以检测痰液样本中的肺结核。对疑似结核病患者的痰液进行去污和浓缩后，进行涂片显微镜检查和培养，并对这些标本进行 LAMP 检测。我们将 LAMP 与涂片显微镜检查进行了比较，分别采用串联和并联的方式与培养进行比较。与培养相比，LAMP 和涂片显微镜检查的敏感性分别为 79.5%和 82.1%，特异性分别为 93.8%和 96.9%。LAMP 和涂片显微镜检查串联的敏感性和特异性分别为 79.5%和 100.0%。LAMP 和涂片显微镜检查并联的敏感性和特异性分别为 82.1%和 90.6%。
结论/意义：在本研究中，LAMP 和荧光涂片显微镜检查的总体效果都很高且大致相似。LAMP 和涂片显微镜检查串联具有很高的特异性（100.0%），可以作为规则纳入测试组合。然而，我们发现 LAMP 在涂片阴性样本中的性能不足。
