An Antagonist of Dihydrostreptomycin and Streptomycin Produced by Pseudomonas pyocyanea

Abstract

DIFFICULTY arises in testing the sterility of dihydrostreptomycin preparations because there are no antagonists which will inactivate the antibiotic in the test cultures, and so allow any contaminating microbes to grow. The reagents used for inactivating streptomycin in such tests, for example, semicarbazide and hydroxylamine, are inactive against dihydrostreptomycin, because the aldehyde group with which they react has been reduced. Moreover, these reagents, being themselves bacteriostatic, are, in fact, unsatisfactory for testing streptomycin, since some contaminating organisms may fail to develop in the presence of the high concentrations necessary to inactivate concentrated solutions of streptomycin¹. A search was therefore made for agents active against both streptomycin and dihydrostreptomycin. Soyabean lipositol, which has been reported to inhibit streptomycin², was found to be inactive against both streptomycin and dihydrostreptomycin. Hydrolysis of the glycosidic linkage by the action of an enzyme preparation from snail gut was tried without success. The production of a streptomycinase by Pseudomonas pyocyanea was reported by Sureau et al.³. A culture filtrate of a strain of this bacterium antagonized streptomycin and dihydrostreptomycin. The active principle in the filtrate diffused through ‘Cellophane’ and was heat stable, and was not, therefore, an enzyme.