Report of rpoB mutation in clinically suspected cases of drug resistant leprosy: A study from Eastern India.
Loading...
Date
2015-03
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Background: The current strategy for leprosy control depends mainly on early case detection
and providing the recommended multidrug therapy (MDT) dosage. Understanding the molecular
mechanisms of drug resistance to each of these drugs is essential in providing effective treatment
and preventing the spread of resistant strains in the community. The progress of molecular
biology research provides a very effi cient opportunity for the diagnosis of drug resistance by
in vitro method. Aim: We aimed to investigate the point mutations within the rpoB gene region of
the Mycobacterium leprae genome, which are responsible for resistance to rifampicin, in order
to determine the emergence of drug resistance in leprosy in the Kolkata region of West Bengal.
Methods: A total of 50 patients with a relapse of leprosy were enrolled in the study. Skin smears
were obtained for estimation of bacillary index and biopsies were obtained in 70% alcohol for
extraction of DNA. The extracted DNA was amplifi ed by M. leprae-polymerase chain reaction (PCR)
targeting rpoB gene region. Every single nucleotide base in the sequence is aligned to reference
sequence and identity gaps were determined by NCBI – BLAST. Later in-silico analysis was done
to identify the changes in the translated protein sequences. Results: A mutation at the base pair
position 2275405 where G is replaced by C in the M. leprae genome, which corresponds to the
coding region of rpoB gene (279 bp – 2275228 to2275506), was observed in two patients. This
missense mutation in CAC codon brings about a glutamic acid to histidine change in the amino
acid sequence of RNA polymerase beta subunit at the position 442 (Glu442His), a region specifi c
for rifampicin interaction, which might be responsible for unresponsiveness to rifampicin by
manifesting a stable bacteriological index in these 2 patients even after completion of 24 months
of multibacillary multi-drug therapy (MB-MDT). Limitations: The major limitations of multipleprimer
PCR amplifi cation refractory mutation system (MARS) assay is that it capable of detecting
mutation at codon 425 and cannot distinguish any silent amino acid changes. Conclusion: The
study indicates the existence of rifampicin drug resistance in Eastern India.
Description
Keywords
DNA Sequencing, drug resistance, point mutations, rifampicin, RNA polymerase beta subunit
Citation
Reja Abu Hena Hasanoor, Biswas Nibir, Biswas Supratik, Lavania Mallika, Chaitanya Vedithi Sundeep, Banerjee Surajita, Maha Patra Prasanta Sinha, Gupta Umesh Dutta, Patra Pradip Kumar, Sengupta Utpal, Bhattacharya Basudev. Report of rpoB mutation in clinically suspected cases of drug resistant leprosy: A study from Eastern India. Indian Journal of Dermatology, Venereology and Leprology. 2015 Mar-Apr; 81(2): 155-161.