Experimental Botryomycosis Produced by Pseudomonas Aeruginosa

Guinea-pigs intratesticularly challenged with small doses of Pseudomonas aeruginosa developed local abscesses with actinomycetoid granules measuring up to 300 ¼m in diameter; metastatic foci of infection in the lungs also contained granules. An eosinophilic shell supporting a crown of eosinophilic clubs is a noteworthy characteristic of the young granules produced by all three of the strains of Ps. aeruginosa studied. Granules were visible as early as 4 days after the inoculation of 0.1-ml doses of suspensions containing 104 bacteria per ml. No granules were produced in the mice challenged intraperitoneally.

Two of the test strains of Ps. aeruginosa were isolated from plant debris accessible to wild animals, insects and other arthropods. The third strain was isolated from a human case of otitis media.

The observations recorded in this article were made during the development of a research project supported by the Universidad de la Republica, Uruguay, and by the United States Army.

The authors are indebted to Dr Maria L. Iraola de Toledo for histopathological facilities and to Mr R. Cesarco for the photographic work.