Experimental Studies on Mice Challenged Subcutaneously with Pseudomonas aeruginosa

Abstract

Summary

By use of the subcutaneous route, chronic Pseudomonas aeruginosa infections were established in normal mice undebilitated by burn wounds or leukopenic agents. Using a 21-day holding period, an LD₅₀ value of 4.6 × 10⁸ colony forming units was obtained. After subcutaneous infection, the dermis was completely necrosed with the lesions reaching deep into the subcutaneous tissue and musculature within 3-4 days. Ecthyma gangrenosum-like skin lesions at the site of infection appeared during this time period. By 7-15 days all mice exhibited a systemic infection. Both the livers and lungs showed a great deal of hemorrhage and frequently contained large necrotic foci, while the kidneys showed petechial hemorrhage and occasional renal abscesses. The susceptibility to infection was markedly increased by use of various antineoplastic agents and suprarenal hormones. However, the type of tissue damage or severity was not significantly altered as compared to infected mice which had not received any of the chemical agents.

This investigation was supported by the Office of Naval Research Grant N-00014-69-0235-0002, the National Institutes of Health general research support Grant 5 S01 RR 05384, and the National Science Foundation Graduate Traineeship Grant GZ 2033.