Thiacetazone: in vitro activity against Mycobacterium avium and M. tuberculosis.

Bacteriostatic and bactericidal activity of thiacetazone was determined for 68 M. avium clinical isolates and 14 wild drug-susceptible M. tuberculosis strains. The drug had equally low bactericidal activity against both mycobacterial species. The inhibitory activity against most of the M. avium strains was greater than it was against M. tuberculosis. The broth determined MICs for 65 of 68 M. avium strains were between 0.02 and 0.15 micrograms/ml, while the MICs for M. tuberculosis ranged from 0.08 to 1.2 micrograms/ml.