[Various principles of detecting the producers of beta-lactamase inhibitors among soil Actinomycetes].

: Principles of detecting organisms producing beta-lactamase inhibitors among soil actinomycetes were developed. For detecting such cultures it was recommended to use the Gauze agarized medium No. 1 supplemented with beta-lactam antibiotics. Benzylpenicillin proved to be the most efficient. Various liquid fermentation media for detecting the inhibitory activity of soil actinomycetes were compared. Two media were the most favourable i.e. the glucose-yeast medium No. 18/3 and the soybean-glucose medium with Na2SO4 and CoCl2 No. 20/3. The use of test cultures with relatively low resistance to benzylpenicillin was shown expedient in screening cultures producing beta-lactamase inhibitors. Test cultures with high resistance should be used in more detailed characterization of the selected cultures.