Studies on the Mechanism of Sulfonamide Bacteriostasis, Inhibition and Resistance

Abstract

The bacteriostatic action of five sulfonamide drugs was determined on a strain of S. aureus, using a relatively simple medium which was found to support adequate growth. Nicotinamide, thiamin, coenzyme I and biotin had no inhibitory effect on sulfonamide bacteriostasis. Uracil, pyruvate and adenylic acid in combination, but not singly, partially inhibited the effect of bacteriostatic concentrations of sulfaguanidine. Para-aminobenzoic acid inhibited the bacteriostatic action of all the sulfonamide drugs. Methionine and nucleic acid had no inhibitory effect on sulfonamide bacteriostasis when tested with the control strain of S. aureus. The strain of staphylococcus was made resistant to sulfonamide action. With partially resistant strains, methionine inhibited sulfonamide bacteriostasis but it did not prevent the development of fastness. Nucleic acid partially prevented the development of resistance of staphylococci in the presence of sulfaguanidine. It is suggested that yeast nucleic acid may contain a weak inhibitor of the action of sulfaguanidine on S. aureus.