PCR based molecular detection of M. tuberculosis and comparison of its efficacy against AFB based bacteriological detection in diagnosis of Pulmonary Tuberculosis in Nepal.

Abstract

Introduction: Tuberculosis is high burden infectious disease in Nepal. Diagnosis strategy for tuberculosis includes Chest X-Ray, Ziehl-Nelson staining method and culture. Culture is considered to be a “gold standard” in TB diagnosis; however, it takes almost 3 weeks to do culture which affects rapid diagnosis of TB. This study investigates molecular based TB diagnosis and compares the result with the AFB staining.

Methods: Sputum samples from the National Tuberculosis centre (NTBC), Sano Thimi, Nepal were tested with Real Time PCR (QPCR) based assay for MTB detection at the affiliated laboratory of the Center for molecular Dynamics Nepal (CMDN), Kathmandu, Nepal.

Results: Out of 47 samples, 7 AFB positive samples yielded quantifiable QPCR positive result. However, of the 40 AFB negative samples assessed, 3 were found to contain quantifiable amount of M. tuberculosis using TB DNA detection. This amounts to 6.38% under detection using just AFB microscopy alone.

Conclusions: There is added benefits of using PCR in detection of M. tuberculosis .This method, if used in conjunction with traditional AFB will provide a more rapid, reliable and accurate diagnosis of M. tuberculosis.