1*Karmacharya, D., 1Dixit, S.M., 2Shrestha, L., 1Bajracharya, B., 1Dulal, P and 2P. Malla
1Center for Molecular Dynamics Nepal (CMDN), Prasuti Griha MargKathmandu, Nepal
2National TB Center, Thimi, Nepal
*Author for correspondence (firstname.lastname@example.org)
A baseline study involving forty eight (48) sputum samples from suspected pulmonary tuberculosis (TB) cases based on available staining methods was carried out with the aim of comparing those results with those obtained using real time RT-PCR detection. Samples were comparatively assessed using microbiological methods at the National TB Center, Thimi, Nepal and real time quantitative PCR (QPCR) methodology at the Center of Molecular Dynamics Nepal (CMDN), Kathmandu, Nepal. The microbiological assessments applied were as per conventional DOTS regime- Smear Microscopy (Ziehl-Neelsen staining or AFB staining). The QPCR assay used targeted IS6110, a 12.7 kb fragment of M. tuberculosis not found in other Mycobacterium sub-species. Out of 48 samples that were processed, 7 AFB positive samples also yielded quantifiable QPCR positive results. However, of the 41 AFB negative samples assessed, three were found to contain quantifiable amounts of M. tuberculosis using QPCR method of detection. This amounts to 6.25% false negative results obtained using traditional microbiological methods alone, in TB diagnosis. The findings from this preliminary study demonstrate the need to deploy highly specific and sensitive genomic based method of detection of M. tuberculosis in conjunction with traditional AFB to come up with rapid, reliable and accurate detection of M. tuberculosis.