The frequency of drug resistance mutations in Mycobacterium leprae isolates in untreated and relapsed leprosy patients from Myanmar, Indonesia and the Philippines.
BACKGROUND
The magnitude of drug resistance in Mycobacterium leprae to dapsone, rifampicin, and ofloxacin was studied in three Southeast Asian countries with a high prevalence of leprosy.


METHODS
M. leprae from the skin of leprosy patients was collected in North Maluku and North Sulawesi in Indonesia, Yangon in Myanmar, and Cebu in the Philippines. Mutations in the drug resistance determining regions in the folP1, rpoB, and gyrA genes, which have been proven to confer resistance, were analysed. In addition, samples from 51 newly diagnosed cases and 13 patients with leprosy relapse in Cebu were submitted for susceptibility testing in the mouse footpad.


RESULTS
Of 252 isolates obtained from new cases, 3% were dapsone resistant and 2% were rifampicin resistant. In samples taken from patients with relapsed leprosy (n = 53), significantly more resistance mutations were detected: 15% had dapsone resistance mutations, and 8% had rifampicin resistance mutations. Two patients with relapsed leprosy had mutations for both dapsone and rifampicin resistance. No mutations conferring quinolone resistance were detected. No mutations were detected in the folP1 gene of M. leprae isolates with a low degree of resistance to dapsone.


CONCLUSIONS
Detection of drug-resistant cases by mutation detection in the drug resistance determining region of the genome is a practical method for monitoring resistance. A comparison of the results obtained in this study with previous data obtained prior to the use of multidrug therapy (MDT), does not indicate clearly whether the magnitude of drug resistance has changed. Larger studies of resistance mutations in M. leprae isolated from patients with relapsed leprosy are needed to confirm our results.


CONCLUSIONS
We recommend monitoring the magnitude of drug resistance globally, by testing M. leprae DNA from relapse cases and a representative sample of new cases.
Matsuoka
Masanori
M
Leprosy Research Centre, National Institute of Infectious Diseases, Tokyo, Japan. matsuoka@nih.go.jp
Budiawan
Teky
T
Aye
Khin Saw
KS
Kyaw
Kyaw
K
Tan
Esterlina Virtudes
EV
Cruz
Eduardo Dela
ED
Gelber
Robert
R
Saunderson
Paul
P
Balagon
Victoria
V
Pannikar
Vijaykumar
V
D017931:DNA Primers; D004269:DNA, Bacterial / Q000032:analysis; D024881:Drug Resistance, Bacterial; D006801:Humans; D007214:Indonesia / Q000453:epidemiology; D007917:Leprostatic Agents / Q000494:pharmacology; D007918:Leprosy / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology; D009154:Mutation; D009166:Mycobacterium leprae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D010679:Philippines / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D012008:Recurrence
D017931:DNA Primers; D004269:DNA, Bacterial; D007917:Leprostatic Agents