Virulence of Pseudomonas Infection in Burned Rats and Mice

Abstract

Most strains of Pseudomonas aeruginosa isolated from patients were lethal to burned mice but rats were relatively resistant and died of certain strains only. In burned rats, silver sulfadiazine (1.0%) applied daily beginning 24 hours postseeding with ratvirulent organisms resulted in 11.2% mortality compared to 12.5% mortality after treatment with mafenide. With certain strains, death occurred after treatment with mafenide but not with silver sulfadiazine. The effect of silver sulfadiazine was dose-related. In mice seeded with human-virulent strains (which were not lethal to rats) or strains lethal to both species the mortality was less than 20% with silver sulfadiazine and 83% with mafenide. Silver sulfadiazine proved effective in both rats and mice infected with virulent strains of Pseudomonas; mafenide was equally effective in rats but relatively ineffective in mice.