Abstract
The sensitivity of the atypical mycobacterial strains to various drugs other than antituber'culous drugs was studied in vitro using Dubos Tween Albumin liquid medium. The atypical mycobacterial strains tested were chosen from 53 strains including 7 photochromogens (M. kansasii), 8 scotochromogens, 30 nonphotochromogens (M. intracellulare) and 8 rapid growers.
Among the commonly used antibiotics the following was studied; Potassium Benzylp e nicillin (PC-G), Sodium Ampicillin (AB-PC), Sodium Cloxacillin (MCI-PC), Kitasamycin (LM), Cephaloridine (CER), Aminodeoxykanamycin (AKM), Demethylchlortetracycline (DMCT), Paromomycin (PRM) as well as two anti-neoplastic agents, Bleomycin (BLM) and Mitomycin C. A phenazine derivative Riminophenazine B 663, which is being investigated as an anti-leprotic agent, and an antifungus agent BAY b 5097 were also studied.
When the growth of mycobacteria was inhibited at t he concentrations of O.78 m cg/ml or less of any drug, the drug was defined as tentatively sensitive, and under this condition over fifty per cent of the nonphotochromogens (M. intracellulare) were sensitive to DMCT (63%)and PRM (53%). (The numbers in the parentheses are the percentages of the sensitive stra ins.)The Minimal Inhibitory Concentrations of BLM and Mitomycin C were O.78 mcg/ml or less in 37% and 48% of the nonphotochromogens, respectively. B 663 showed fairly constant in vitro effect to the atypical mycobacteria tested, and 75% of the nonphotochromogens were inhibited -their growth at the concentrations of O.156 m cg/ml to 0.625 m cg/ml. Photochromogen s seemed to be most sensitive to B 663 and the rapid growers were less sensitive than the other strains. All the strains tested were resistant to BAY b 5097.
