[Characteristics of Streptomyces kanamyceticus mutants resistant to aminoglycoside antibiotics].

The influence of the antibiotic activity level in strains of S. kanamyceticus on their resistance to kanamycin and other aminoglycosides was studied. Correlation between the activity of the strains and their resistance was observed. A collection of induced mutants of S. kanamyceticus with increased resistance to kanamycin, gentamicin, neomycin and apramycin was set. Cross resistance in the mutants to the aminoglycosides under different conditions (fermentative and not fermentative) was characterized. An increase in the resistance to gentamicin, neomycin and apramycin correlated with an increase in the resistance to kanamycin. The effect of the mutations of resistance to the aminoglycosides on the antibiotic activity of S. kanamyceticus was investigated. It was found that the population of the gentamicin resistant mutants was characterized by an increased average antibiotic activity and a higher number of the plus variants which is promising for the improvement of the strains with respect to higher levels of the kanamycin synthesis. The dynamics of the kanamycin synthesis in the initial strain of S. kanamyceticus was compared with that in its aminoglycoside resistant mutants. The apramycin resistant mutant was characterized by a significant delay in the beginning of the kanamycin synthesis.