Molecular screening for primary drug resistance in M. leprae from newly diagnosed leprosy cases from India

Background: India records an Annual New Case Detection Rate (ANCDR) of 9·98 per 100,000 population, with a range of 0·42–81·7, across its various states. Although there is not much evidence available for presence of primary drug resistance in leprosy, it is essential to know such information on a periodic basis, in such high endemic regions, with increasing incidence of new leprosy cases. Objective: The study was undertaken to screen for Mycobacterium leprae drug resistance to dapsone, rifampicin and ofloxacin by PCR sequencing of folP1, rpoB, and gyrA genes respectively. Methods: Prospective community based study conducted during 2011–14, with samples collected from two districts- Adilabad and Hyderabad, Andhra Pradesh (presently Telangana state), Sonepur and Koraput, of Odisha state of India, for molecular drug resistance analysis of M. leprae. PCR and gene sequencing was carried out on the Slit Skin Samples SSS) collected from the enrolled subjects. An attempt was made to screen M. leprae PCR as a bacteriological tool for diagnosing leprosy. Results: During the study period 234 new leprosy cases were enrolled out of which 74% cases were multibacillary (MB) and 26% were paucibacillary (PB). 20% of the 214 specimens tested were positive for PCR of fol P1, 11%, positive for rpoB and 35% for gyrA. None of the isolates demonstrated drug resistance. Conclusion: Study findings indicate the absence of drug resistance in new leprosy patients and also suggest reintroduction of skin smear examination in to routine practice. PCR with some improvements may also be included for specific diagnosis of leprosy.