[Biological properties of laboratory strains and clinical isolates of mycobacteria multiresistant to antitubercular preparations].

Multiresistant M. tuberculosis strains show varying drug resistance, virulence and growth rates. The count of cells of some multiresistant strains in the guinea-pig parenchymatous organs after intracardiac inoculation was comparable with that of after inoculation with clinical isolates. Furthermore, some multiresistant strains were not inferior to sensitive clinical isolates. The findings lead to the conclusion that there is a wide range in the virulence of multiresistant strains and hence they can present an epidemiological hazard.