1989 Volume 64 Issue 8 Pages 511-518
Comparing minimal inhibitory concentrations (MICs) determined in variousnontuberculous mycobacteria with those for Mycobacterium tuberculosis strains, whichwere isolated from patients who were untreated previously by any antituberculosis drugs, clinical efficacy of isoniazid and ethambutol in the treatment of nontuberculousmycobacteriosis was evaluated. The MICs of isoniazid for M. tuberculosis strains were0.03-0.1μg/ml, whereas the MICs for M. xenopi strains were 0.1-0.4μg/ml, those for M. szulgai 0.2-0.8, and those for M. kansasii 0.8-1.6μg/ml.
The fact that M. xenopi strainsare susceptible to isoniazid was reported previously, and in this study, it was shown that M. szulgai and M. kansasii are also considerably susceptible to isoniazid.
Isoniazid may beuseful in the treatment of infection due to these mycobacteria.
The MICs of ethambutolfor M. tuberculosis strains ranged from 0.8 to 3.13μg/ml.
The percentages of strains of various mycobacteria, which are susceptible to 3.13μg/ml ethambutol, were 100% in M. szulgai, 100% in M. nonchromogenicum, 90% in M. gordonae, 88% in M. marinum, 77% in M. kansasii, 46% in M. malmoense, and 30% in M. scrofulaceum.
In contrast, the percentage in M. avium complex strains remained only 19%.
It has been suggested that ethambutol iseffective in the treatment of diseases caused by M. szulgai, M. marinum and M. kansasii.
