[Use of selective media with lincomycin for the directed screening of antibiotic producers].

Relation between lincomycin resistance of Micromonospora cultures freshly isolated from soil samples and their capacity for production of antibiotics related to lincomycin by the structure or mode of action was shown. 32 cultures of Micromonospora were isolated from soil platings containing 50--100 microgram/ml of lincomycin. Crude antibiotic substances were recovered with the method of organic solvent extraction from 10 cultures possessing pronounced antibiotic activity. Selective inactivity (MIC more 1000 microgram/ml) of the crude substances with respect to the lincomycin resistant variant of Staph. aureus 209 p was observed, 2 of them having no inhibitory effect on the erythromycin resistant variant of the staphylococcus. The crude antibiotics inhibited the growth of the initial strain of the staphylococcus and its other antibiotic resistant variants in concentrations of 0.5--10 microgram/ml. It was demonstrated with the use of gas chromatography and mass spectrometry that one substance was lincomycin and 4 substances were known macrolides. Efficiency of the simple method of directed screening of antibiotics belonging to definite groups is indicated. Resistance of actinomycetes freshly isolated from natural substrates to various antibiotics is used as the criterion for antibiotic screening. The method provides detection of various antibiotics which are analogs in the structure or mode of action of the selecting antibiotic used for the screening.