Molecular mechanisms of mycobacterium tuberculosis strains resistance to rifampicin and isoniazid

: The levels and spectra of the drug resistance of clinical M. tuberculosis strains were defined. There was a relationship of treatment regimens to the drug resistance of mycobacteria isolated from the strains. The fragments of genes rpoB, inhA, and katG were analyzed by polymerase chain reaction and sequencing. In addition to earlier identified substitutions, new mutations were found in rpoB: A-->T/233, G-->A/395, C-->T/232, G-->T/202, C-->T/221, C-->T/260, GA-->TT/202-203, delta 199-207 ATGGACCAG. Strain 12/7 was found to have 30 point mutations leading to substitution of only 3 amino acids and to have GGG(Gly)354 deletion as well. Most mutations in this strain are "silent". Substitutions at 944 and 463 positions were revealed in katG.