[Histopathological observations of experimental hematogenous infection with Pseudomonas aeruginosa in mice (author's transl)].

The effect of intravenous injection of Pseudomonas aeruginosa in mice was studied in various conditions : dose of bacteria injected (2.5 X 10(6) to 4.5 X 10(7)) , moment of necropsy (one hour to 4 months after infection), number of injections (one, two and eight). Gross and microscopic examinations of tissues included kidney, lung, spleen and liver. The frequency, the type and the time of appearance of the lesions depend upon the dose of organisms, upon the individual susceptibility of the mouse and upon the number of injections. Abscesses preferentially localised in kidneys appeared in mice that received only one injection of bacteria. They were visible to the naked eye as soon as two days after inoculation with a large dose. Granulomatous inflammatory reaction was observed in the different tissues, however it was predominantly seen in the kidney and in animals that received several injections. In the liver and the spleen hyperplasia and hypertrophy of lymphoid, myeloid, megacaryocytic and mononuclear phagocytic cells were observed. This model of experimental pyelonephritis due to P. aeruginosa seems to us useful to study the factors promoting localisation and multiplication of this organism in a tissue.