[Fluctuation in the ratio between drug-resistant and -susceptible M. tuberculosis bacilli which were isolated from patients with prolonged anti-tuberculosis treatment].

Purpose: In this study, we examined the fluctuation in the ratio between strains of tuberculosis bacilli resistant and susceptible to the anti-tuberculosis drugs.

Material & Method: We selected the cases in which the bacilli acquired drug resistance during the therapy and the cases in which drug resistance was fluctuating during prolonged anti-tuberculosis treatment. We selected the isolates throughout the medication period, and the selected isolates were separated into respective single colonies.

[A study of INH 0.1 microgram/ml resistant M. tuberculosis strains assessed by BrothMIC MTB-1 method].

In the antimycobacterial susceptibility test for INH using the egg-based Ogawa media, 3 concentrations (0.1, 1, or 5 micrograms/ml) of INH were used, and 1 microgram/ml was used as a critical concentration for INH resistance. However, it was controversial whether INH 0.