[Sensitivity of m. kansasii strains to various antibiotics and chemotherapeutics in vitro and in vivo (author's transl)].

Sensitivity of 40 strains of M. kansasii (var. luciflava) to various antibiotics and chemotherapeutics in vitro and in vivo was examined. The strains showed considerable individual variability in their susceptibility in vitro, most were more resistant to isoniazid and PAS and about one half of the investigated strains to streptomycin, too, if correlated to "wild" strains of M. tuberculosis. Susceptibility to ethionamide, thiosemicarbazone (Conteben), viomycin, kanamycin and cycloserine appears to be the same as in the case of M. tuberculosis strains, but the resistance to pyrazinamide is higher. Good effect has been observed in vitro with rifampicin, ethambutol, capreomycin and phenazine derivative B 663. Oleandomycin and gentamycin are ineffectual in the dosages of drugs we used. The activity of most of these drugs was observed in experimental infections of white mice--in mono-therapy and in various combinations-provoked by different strains of M. kansasii. The main criterion of the effectivity of the treatment was the enumeration of viable mycobacterial units in the lungs of the mice in ten-days intervals; in one part of the experiments the histological examination of the various organs of the mice was performed. The drugs of the I. and II. line of antituberculotics were ineffective or showed only a slight effect. A very good effect of rifampicin, ethambutol and phenazine derivative B 663 in monotherapy and in multiply drug therapy was observed.