Mutation in the rpoB Gene of Mycobacterium leprae from Korean Laprosy Patients

A fast and easy PCR-SSCP method was developed and assessed for the early detection of rifampin-resistant Mycobacterium leprae in skin biopsy samples from Korean leprosy patients. The 190 bp of the rpoB gene, in which mutation is known to cause resistance to rifampin, was amplified by PCR and then analyzed by SSCP and DNA sequencing, All PCR products showing mobility shift on PCR-SSCP contained mutations, demonstrating that this method can be used for an early diagnositic method to detect a putative rifampin-resistant M. leprae strain. DNA sequence analysis revealed that 19 of 34 patient samples contained M. leprae strains with missense mutations in the rpoB gene: five were the same mutations previously reported to cause rifampin resistance and eight were the new type of mutatios that likely cause rifampin resistance. These newly identified dmutations, whose all five cytosine bases of four amino acids were substitued with thymine, were found at different sites from those reported in Mycobacterium tuberculosis or M. leprae. Therefore, they may provide additional clues to understand the molecular biological basis on the rifampin resistance of M. leprae.