Comparative assessments of polymerase chain reaction (PCR) assay of repetitive sequence (RLEP) and proline rich antigen (PRA) gene targets for detection of Mycobacterium leprae DNA from paucibacillary (PB) and multibacillary (MB) patients in Côte d’Ivoire

Several Mycobacterium leprae gene targets could be used for leprosy diagnostic.  PCR sensitivity of some gene targets for specific clinical isolates has not yet been established in Cote d'Ivoire. The present study was conducted to compare the sensitivity of the Pra gene and RLEP targets in the detection of M. leprae from nasal mucus and ear dermal pulp fluid samples from paucibacillary and multibacillary patients. Leprosy patients were classified into Paucibacillary and Multibacillary types. DNA extraction from samples was performed by a guanidine thiocyanate method. PCR technique was performed for M. leprae detection from samples. 84.94 % were positive for RLEP target while 69.94 % were positive for the Pra gene target. For paucibacillary cases with bacteriological index negative, 180 one 258 (69.76 %) were positive for the RLEP target and 193 one 258 (74. 80 %) were positive for Pra gene target. Concerning multibacillary cases with bacteriological index positive samples, 100% of the samples were positive for RLEP target and 65.21 % for Pra gene target. The Pra gene target showed a large difference in detection of M. leprae between paucibacillary and multibacillary forms in leprosy patients. In conclusion, PCR-Pra could be a useful tool for diagnosis of leprosy, mainly in cases of Paucibacillary leprosy or when bacilloscopy is negative. The PCR-RLEP appear to be the best target for early diagnosis of leprosy.