Defining critical concentrations of the second line TB drugs (cycloserin and PAS), to establish drug susceptibility testing on the liquid medium of Middlebrook 7Н9

Abstract

In order to determine critical concentrations of the second line TB drugs, namely cycloserin and PAS, and to use these critical concentrations for establishment of drug susceptibility testing by the proportional method on the liquid medium of Middlebrook 7H9 in the Bactec MGIT 960, 441 cultures of M. Tuberculosis were tested after inoculation of 2534 samples obtained from 1330 TB patients living in Vladimir Region. Upon results of drug susceptibility testing on solid media 4 groups of M. tuberculosis strains, susceptible and resistant to PAS and cycloserin have been identified. Results of searching for minimum inhibiting concentrations of PAS and cycloserin for these groups of strains in the liquid medium of Middlebrook 7H9 allowed finding critical concentrations for PAS (2.0 mkg/ml) and cycloserin (15.0 mkg/ml).

Keywords

• чувствительность к паск и циклосерину
• критические концентрации