[Development of bruneomycin and rubomycin resistance in mouse lymphadenosis tumor cells and Staphyloccus when these preparations are used separately or together].

Two sublines of mouse lymphadenosis (L-5178) resistant to bruneomycin and rubomycin used alone, as well as a subline with induced resistance to the combination of these drugs were employed in the study. The studies showd that in separate use of rubomycin and bruneomycin the tumor cell resistance to the respective drug was evident at the 10th passage. After 30 passages neither bruneomycin nor rubomycin produced reliable inhibition of the tumor growth in the respective subline of lyphadenosis. When the antibiotics were used in combination, no significant decrease in sensitivity of the tumor cells to either of the drugs or their combination was observed. The experiment with Staph. aureus also showed that the rate of the resistance increase to the drug combination was lower than that to the drugs used alone. Therefore, it was shown that the combined use of bruneomycin and rubomycin provided a means for preventing to a significant extent of development of the resistance in lymphadenosis tumor cells and Staph. aureus. This may be considered as an indication for clinical trials of the above combination.