Effects of preservatives, steroids, and ethylenediaminetetraacetate on the antimicrobial activity of sulfacetamide.

The effect of EDTA (ethylenediaminetetraacetate), steroids, and preservatives on the antimicrobial activity of 10% sodium sulfacetamide solutions was evaluated in this study by kill rate and minimum inhibitory concentration (MIC) using five representative microorganisms. The results indicate that thimerosal-preserved sulfacetamide solutions containing EDTA are more effective against Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus epidermidis, and Candida albicans than similar paraben-preserved solutions. Furthermore, the addition of EDTA improves the kill rate, but not the MIC, for the Pseudomonas, Serratia, and Candida species regardless of the preservative. The combination of a steroid with sulfacetamide does not affect its antimicrobial activity.