Resistance to Tetracycline and Oleandomycin of a Number of Streptomycetes — Producers of Polyketide Antibiotics

Recently, antibiotic resistance of pathogenic and opportunistic microorganisms is one of the primary problems of medicine. Scientists pay considerable attention to the study of genes for resistance of strains of streptomycetes as sources of such genes for microorganisms. The aim of this study was to determine the sensitivity of 9 strains of streptomycetes producing polyketide antibiotics to tetracycline and oleandomycin and to identify possible correlations in resistant and sensitive strains between the level of their resistance and the presence of resistance genes in chromosomes. Methods. 9 strains of producers of polyketide antibiotics were studied: Streptomyces cyanogenus S136, S. fradiae Tu2717, S. glaucescens Tu49, S. olivaceus Tu2353, S. antibioticus 35, S. globisporus 1912, S. aureofaciens 019, S. coelicolor A3(2), S. lividans TK24. Appropriate microbiological (method of serial dilution in agar) and biotechnological (method of computerized analysis of sequences) methods were used. Results. According to the sensitivity to oleandomycin and tetracycline, the studied strains of streptomycetes can be divided into 3 groups. The first group includes strains resistant to both antibiotics — S. coelicolor A3(2) and S. lividans TK24, the second group includes strains resistant to only one of the antibiotics: more resistant to oleandomycin — S. globisporus 1912, S. glaucescens Tu49, S antibiotic 35-1; more resistant to tetracycline — S. olivaceus Tu2353, S. fradiae Tu2717, S. aureofaciens 019. Strain S. cyanogenus S136 is sensitive to both antibiotics. Conclusions. A correlation was found between the level of tetracycline resistance and the presence (the number and similarity of structures) in the genomes of strains S. lividans TK24, S. globisporus 1912, and S. cyanogenus S136 sequences, which are similar to the sequences of tetracycline resistance genes of strain S. coelicolor A3(2).