Bacterial viability after exposure to malachite green. Bacterial strains grown to mid-log phase were diluted to 107 cells/ml and 0.1 ml was plated on 7H10 medium with (green bars) or without (yellow bars) 1 mg/liter of malachite green. Data points show means +/- standard deviations of duplicate. Significantly different from values of H37Rv (p < 0.05)* (p < 0.01)**. All data are representative of two independent experiments.