Department of Molecular Medicine, National Institute of Tuberculosis and Respiratory Diseases, Sri Aurobindo Marg, New Delhi, India.
Department of Molecular Medicine, National Institute of Tuberculosis and Respiratory Diseases, Sri Aurobindo Marg, New Delhi, India.
J Microbiol Methods. 2019 Mar;158:59-65. doi: 10.1016/j.mimet.2019.01.016. Epub 2019 Jan 28.
Confirmatory diagnosis of extra-pulmonary tuberculosis remains a true challenge owing to difficulty in procuring appropriate specimen, inefficient laboratory methods and paucibacillary nature of infection. These obstructions become all the very difficult in pediatric EPTB cases, due to non-specific clinical signs and symptoms, low sensitivity of smear microscopy and culture, lack of awareness among clinicians, etc. AIM OF THE STUDY: The present study aimed to evaluate the diagnostic accuracy of rapid and cost-effective loop-mediated isothermal amplification (LAMP) assay for EPTB diagnosis in children.
A total of 154 cases were analyzed by EPTB-site smear microscopy, culture, PCRs for IS6110, MPB64 & Pab genes, nested PCR and LAMP assay. Single-gene PCRs were performed by custom-synthesized primers. Nested PCR was performed using the 3B BIOTUB Kit and the LAMP assay was done using the Nu-LAMP TB kit.
We observed that the molecular tests displayed 4-fold higher positivity rate (minimum 46%) in comparison to the microbiological tests (maximum 11.03%). In contrast to the composite reference standard, LAMP assay was found to be 79.6% sensitive and 78% specific for EPTB diagnosis in childhood cases.
Our results indicate that LAMP assay is a promising technique for efficient diagnosis of EPTB in children belonging to resource-limited regions.
由于难以获取适当的标本、实验室方法效率低下以及感染菌量少，肺外结核病的确诊仍然是一个真正的挑战。这些障碍在儿科 EPTB 病例中变得更加困难，因为这些病例的临床症状和体征不具有特异性、涂片镜检和培养的敏感性低、临床医生缺乏认识等。
本研究旨在评估快速且具有成本效益的环介导等温扩增（LAMP）检测在儿童 EPTB 诊断中的诊断准确性。
对 154 例 EPTB 部位的涂片镜检、培养、IS6110、MPB64 和 Pab 基因的 PCR、巢式 PCR 和 LAMP 检测进行了分析。单基因 PCR 使用定制合成的引物进行。巢式 PCR 使用 3B BIOTUB 试剂盒进行，LAMP 检测使用 Nu-LAMP TB 试剂盒进行。
我们观察到分子检测的阳性率比微生物学检测高 4 倍（最低 46%）。与复合参考标准相比，LAMP 检测法对儿童 EPTB 的诊断灵敏度为 79.6%，特异性为 78%。
我们的结果表明，LAMP 检测法是一种很有前途的技术，可以在资源有限的地区有效地诊断儿童的 EPTB。
