The Effect of Mafenide on Dihydropteroate Synthase

Using intact bacterial cells, it was found that Pseudomonas aeruginosa was more susceptible to mafenide than Escherichia coli, that p- aminobenzoic acid (pABA) did not reverse or prevent inhibition by mafenide and that pABA itself was inhibitory. Under the experimental conditions used in these studies, pABA was more inhibitory to E. coli than to P. aeruginosa. It is proposed that pABA could be of use in the topical treatment of burn wounds. At the enzyme level, it was shown that mafenide did not inhibit dihydropteroate synthase. Thus, mafenide appeared not to exert its inhibitory effects in the same manner as the structurally related suphonamides. Mafenide is a synthetic antimicrobial agent structurally related to the sulphonamides as well as to p- aminobenzoic acid (pABA). It has low bacteriostatic activity against a wide spectrum of both Gram-positive and Gram-negative bacteria, especially Pseudomonas aeruginosa, a troublesome organism in burn wound tissues. (Js)
Pub. in Jnl. of Antimicrobial Chemotherapy, v25 p25-29 1990.