Resistance to anti leprosy drugs in multi-bacillary leprosy: A cross sectional study from a tertiary care centre in eastern Uttar Pradesh, India

Background: WHO MDT is the main drug regimen for treating leprosy and has been used for more than three decades. Many cases of relapse of leprosy have been reported, which points towards the emergence of drug resistance with the antileprotic drugs. Objectives: To find the resistance with the antileprotic drugs by detecting the mutations in drug resistance determining region of the rpoB, folP1 and gyrA genes of Mycobacterium leprae. Methods: Leprosy patients with bacterial index >= 2 were included in the study. The slides were further processed to extract genomic DNA, and polymerase chain reactions were performed to amplify the drug resistance determining region (DRDR) of rpoB, folP1 and gyrA genes. The samples in which genes could be amplified were subjected to DNA sequencing to detect mutations. Results: Out of 78 samples rpoB gene was amplified in 39 (50%), folP1 in 32 (41%) and gyrA in 45 (57.7%). In 20 (25.6%) samples no gene was amplified. Only 32 samples of rpoB, 25 samples of folP1 and 38 samples of gyrA gene were included in the study, rest were excluded due to sequencing error. No mutation was seen in rpoB gene and in folP1 gene. In gyrA gene samples mutations were seen in 8 (21%) samples, and were present at codon 91 GCA -> GTA (Alanine -> Valine). Limitations: Small sample size and less efficient method to detect resistance. Conclusion: Resistance is not a problem with conventional drugs in MDT. It is more common with quinolones.