USE OF NASBA(R) RNA AMPLIFICATION FOR DETECTION OF MYCOBACTERIUM-LEPRAE IN SKIN BIOPSIES FROM UNTREATED AND TREATED LEPROSY PATIENTS

This study was performed to assess the value of NASBA(R) RNA amplifica tion of a 16S rRNA target for the detection of presumably viable Mycob acterium leprae in sections of skin biopsies from leprosy patients. Th e NASBA positivity rate was 90.4% (84/93) for untreated multibacillary (MB) patients [bacterial index (BI) greater than or equal to 2] and 1 6.7% (8/48) for the untreated paucibacillary (PB) patients (BI < 2). N ASBA positivity showed a good concordance with the presence of solidly stained M. leprae [morphological index (MI)] in skin biopsies from le prosy patients, but no relationship could be demonstrated between the strength of the NASBA signals and the BI. Furthermore, the usefulness of the detection of 16S rRNA by NASBA to monitor the efficacy of lepro sy treatment was investigated using an additional 154 biopsy specimens analyzed from 80 MB patients during the course of treatment. The NASB A positivity rate declined during treatment. A significant decrease wa s observed after only 1-3 months. These results favor the view that de tection of RNA by NASBA may reflect the viability of M. leprae.