To detect and characterize mutations in rpoB, katG and gyrA.
METHODS:
Thirty selected Mycobacterium tuberculosis isolates from the IDS-PGH were subjected to PCR amplification and sequencing. Sequences were compared to the wild type strain H37Rv.
RESULTS:
Mutations were detected in codons 512, 513, 516, 522, 526, 531 and 533 of rpoB, codons 280, 281, 315 and 333 of katG, and codons 90 and 94 of gyrA sequences. The most frequently mutating codons for rpoB, katG and gyrA were 531, 315 and 94, respectively. A clusteringanalysis of the sequences showed occurrence of seven, four and three clusters for the genes rpoB, katG and gyrA, respectively. The eight clusters obtained from the concatenated sequences of the three genes represent the eight potential genotypes of local strains. One cluster represents the wild type straingenotype, another cluster represents the XDR straingenotype, and six clusters represent the MDR straingenotypes.
CONCLUSION:
These findings indicate the utility of multiple RDR sequence analysis in both identifying specific drug resistancemutation and genotyping of various M. tuberculosis isolates.