Effect of Organic Acids on Streptomycin Activity. ∗,†

Abstract

Summary

The addition of 1% pyruvate and fumarate to nutrient broth supported the growth of E. coli in the presence of 10 μg/ml of streptomycin. When the concentration of the acids was increased to 3%, growth took place even in the presence of 150 μg/ml of streptomycin. The streptomycin was not destroyed. The test bacteria growing in the presence of streptomycin and of the organic acids did not become resistant to streptomycin.

Salts of succinic, formic, malic, and maleic acids also exerted some antagonistic effect upon streptomycin. Lactose, as well as lactic, acetic, and propionic acids, glycerol, glycerophosphate, and glucose had no effect upon the growth-inhibiting action of streptomycin on E. coli.

Comparison of the antagonistic effect of pyruvic and fumaric acids against the streptomycin action upon various bacteria, showed considerable variation. E. coli and P. vulgaris were largely protected by the organic acids against the action of streptomycin, whereas A. aerogenes and S. aureus were only slightly affected.