Occurrence of mutations associated with rifampicin and isoniazid resistant in Mycobacterium tuberculosis isolates from patients in Burkina Faso

Genetic mutations are responsible for the high rate of resistance observed in the treatment of tuberculosis. This study aimed at determining the occurrence of mutations associated with rifampicin (RIF) and isoniazid (INH) resistance of Mycobacterium tuberculosis complex (MTBC) isolates. MTBC strains isolated by culture from 110 TB patients diagnosed with resistant to rifampicin (RR-TB) by Xpert MTB/RIF were studied. The isolates were obtained from the National Tuberculosis Reference Laboratory in Ouagadougou. They were identified culturally using Antigenic method (SD Bioline TB Ag MPT64). Polymerase Chain Reaction, PCR (DRplus) was used to detect the occurrence of mutations in the genes associated with resistance katG and inhA promoter for INH, and rpoB for RIF. Out of 103 isolates with RIF resistant, mutations were detected in 87(84.5%) of gene rpoB while no mutation was found in 16(15.5%) of the gene of the isolates even though the wild probes had disappeared. Single mutations were found in the codons D516V (41.7%) and H526Y (17.5%) while combined mutations (single and double) were mostly detected in the codons D516 (51.5%), H526Y (20.4%), S531L (11.7%) and H526D (10.7%) respectively. Single mutations responsible for high-level isoniazid resistance, katG were observed in the codon S315T1 while the combined inhA and katG were detected in the codon C8T and S315T, 16 (14.5%) respectively. The highest mutation occurrence was observed with rpoB516, rpoB526 for RIF and katG315 for INH associated with resistance of MTBC isolates. There is a need to improve molecular assay kit diagnosis to curb the geographic specificity of the target genes needed to detect more possible mutations.