Discrepancies between the results of M.tuberculosis susceptibility testing by phenotypic and genotypic method

The increase in the number of cases of drug-resistant TB and the therapeutic failures in the treatment, imposes the need to optimize the sensitivity tests of M.tuberculosis. There is still no unanimously accepted and reliable method for the laboratory diagnosis of TB and most often the application of several methods is required. Knowledge and synergistic analysis of mutations in the M. tuberculosis genome, evaluation of the results of phenotypic tests with different levels of resistance, as well as information about clinical outcomes will substantially improve the treatment of patients with drug-resistant TB. Evaluation of different types of genotypic resistance, with the description of mutations that confer low or high resistance, is consistent with the level of phenotypic resistance, and also makes it possible to adjust treatment regimens, which in turn positively influence the duration and results of treatment.