Effect of calcium chloride on experimental infection of mice with Pseudomonas aeruginosa

Abstract

Concomitant administration of Pseudomonas aeruginosa and calcium chloride to mice enhanced the virulence of some strains. The 50% lethal dose of P. aeruginosa 5 decreased by more than three orders of magnitude, regardless of the challenge route (intramuscular, subcutaneous, and intraperitoneal injection), while the 50% lethal dose of strain N10 did not decrease. When challenged intramuscularly with 10(4) organisms of strain 5 or strain N10 mixed with calcium chloride, both strains multiplied at the local site of injection. Strain 5 subsequently caused systemic infection, while strain N10 did not. The virulence-enhancing effect of calcium chloride can be successfully applied in protection assays for immunized mice challenged with strain 5.