Detection of M. leprae by reverse transcription- PCR in biopsy specimens from leprosy cases: a preliminary study.

A reverse transcription (RT)-PCR assay targeting 16S rRNA of Mycobacterium leprae has been used to detect M.leprae specific nucleic acids. This study has been initiated to gain experience about detection of RNA from seven biopsy specimens by RT-PCR assay using species- specific primers described earlier. These biopsy specimens were from clinically confirmed and untreated leprosy cases belonging to BB and BL types. The earlier reported method was established in our laboratory. 171 bp fragment by RT-PCR was amplified from 4/7 cases. The positives results by RT-PCR were from the biopsies from fresh or short term treated cases whereas negative results were from specimens from long term treated cases showing clinical features of relapse. DNA targeting PCR (36 KDa) showed positivity in both groups. These results suggest that RT-PCR positivity possibly reflect the presence of viable organisms. Thus as earlier predicted RT-PCR assay may be useful for viability determinations for assessing the response to chemotherapy as well as presence of persisters in relapse cases.