Genetic and biochemical studies on drug-resistant mutants in Mycobacterium smegmatis.

Genetic analyses of the loci conferring resistance to antibiotics known to affect protein synthesis were made employing the conjugation system of Mycobacterium smegmatis. By the complementation tests, vic (viomycin–capreomycin-resistant) mutants were classified into two different groups; cistrons A and B. Neomycin–kanamycin-resistant (nek) mutants, on the contrary, fall into a single cistron. Erythromycin-resistance (ery) locus was linked to vic–nek region. The map order deduced was argB, argA, (vicA, vicB), nek, ery. Biochemical studies showed that strains resistant to streptomycin, neomycin–kanamycin or viomycin–capreomycin had altered ribosomes.