Rapid diagnosis and simultaneous identification of tuberculous and bacterial meningitis by a newly developed duplex polymerase chain reaction.

The present study describes the development and evaluation of a duplex polymerase chain reaction (D-PCR) for diagnosis and simultaneous identification of tuberculous meningitis (TBM) and bacterial meningitis (BM) in a single reaction. A D-PCR with primers amplifying portions of the Mycobacterium tuberculosis IS6110 and the eubacteria 16SrDNA sequence in a same reaction mix was developed and tested on DNA extracted from 150 clinical CSF samples from different categories (TBM = 39, BM = 26, control infectious and non-infectious category = 85). The results indicate a clear differentiation between bands for eubacteria and M. tuberculosis with an analytical sensitivity of 10(3) cfu/ml for eubacteria and 10(2) cfu/ml for M. tuberculosis. When evaluated in clinical samples, D-PCR overall diagnosed 100 % confirmed TBM and 100 % confirmed BM cases with overall specificity of 96.5 %. D-PCR can be an effective tool for diagnosis and simultaneous identification of TBM or BM in a single PCR reaction. It saves time, cost, labour and sample amount and help in administration of appropriate antimicrobial therapy. The proposed diagnostic assay would be helpful in correct and rapid management of TBM and BM patients.

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.