Drug resistance in Mycobacterium leprae from patients with leprosy in China.

Summary Background Previous studies of drug resistance have shown that mutations in the drug resistance-determining region (DRDR) in the Folp1, RpoB and GyrA genes of Mycobacterium leprae are responsible for resistance to dapsone, rifampin and ofloxacin, respectively. Aim To investigate the prevalence of mutations in genes associated with drug resistance in M. leprae isolates from patients with leprosy in Shandong Province. Methods The DRDR in the FolP1, RpoB and GyrA genes was analysed by direct sequencing of the PCR product from 85 isolates of M. leprae sampled from patients with leprosy in Shandong, China. Results Sequencing results were obtained for FolP1, RpoB and GyrA in 67, 57 and 81 of the 85 samples, with mutation rates of 1.5% (1/67), 8.8% 5/57 and 25.9% (21/81). Three multidrug-resistant samples were found among the new cases: one had a mutation in both Folp1 and RpoB, while the other two had a mutation in both RpoB and GyrA. Conclusions Primary resistance appears to be to either single drugs or combinations of two drugs. The resistance rate to dapsone seems to be low. To our knowledge, this is the first case of multidrug-resistant M. leprae from China.