Reverse Transcriptase Polymerase Chain Reaction: A Promising tool for Rapid Identification of Mycobacterium tuberculosis

Tuberculosis remains a major cause of morbidity a mortality globally. Rapid diagnosis of MTB is important for prevention of tuberculosis. Sputum smear microscopy does not differentiate between viable and dead bacilli. Ribosomal RNA (rRNA) based methods are one of the important tools for rapid detection of viable MTB from patients samples. The aim of the study was to detect MTB in Sputum samples of follow up patients of MTB by Reverse Transcriptase RT PCR and to analyze the results of RT PCR with smear microscopy. 211 follow up sputum Samples were received through the Revised National Tuberculosis Control Programme (RNTCP). RNA was extracted from culture isolates and then processed by Reverse Transcriptase RT PCR targeting I6SrRNA gene. Direct smear microscopy of all sputa were done prior to processing. The RT PCR assay showed overall 59.87% accuracy. Out of a total 211 samples, 66 (31.2 %) were positive and 145 (68.7) were negative for Reverse transcriptase RT PCR. Of 66 RT positive samples, 38 (57.5 %) were smear positive and 28 (42.4 %) were smear negative. Of 145 RT negative samples, 33 (15.6%) were smear positive and 112 (53%) were smear negative. RT PCR could detect viable MTB in smear negative samples with 57.88% sensitivity (CI 95%, 44.79% to 69.66%) and with 77.24% specificity (69.55% to 83.79%). To conclude, Reverse transcriptase RT PCR may prove to be a promising tool for early detection of Mycobacterium tuberculosis.