Loop-mediated isothermal amplification for rapid and reliable diagnosis of tuberculous meningitis

Diagnosis of tuberculous meningitis (TBM) is often difficult. A reliable, simple, and rapid diagnostic test that can be performed in any standard laboratory could be helpful in TBM diagnosis. In this study, a loop-mediated isothermal amplification assay (LAMP) was evaluated to rapidly detect and diagnose TBM infection and was compared to the performance of nested PCR. Six specific primers were used to recognize the IS6110 genomic sequence from Mycobacterium tuberculosis, which included one forward outer primer, one reverse outer primer, two respective inner primers, and two loop primers. The optimum reaction temperature and time were 63°C and 60 min, respectively. Nested PCR was performed targeting the IS6110 region from M. tuberculosis using a commercial kit. The LAMP method yielded a sensitivity of 88.23% and a specificity of 80%, compared to the nested-PCR assay, which yielded a sensitivity of 52.9% and a specificity of 90% for TBM diagnosis. Comparative experiments showed that the LAMP assay is a rapid, sensitive, and specific method to detect TBM infection and that it is superior to the nested-PCR assay. LAMP is very simple, and it can be performed in any laboratory and in rural settings.