Pseudomonas aeruginosa exoproducts as pulmonary virulence factors.

An experimental animal model of chronic pseudomonas pneumonia was used to document the production of potential virulence factors by Pseudomonas aeruginosa during the infection. The production of exotoxin A, proteolytic enzymes, and the serotype-specific lipopolysaccharide and slime-layer antigens during the infection was examined by solid-phase radioimmunoassay of serum from infected rats and by indirect immunofluorescence tests of their lung tissue. Rats inoculated intratracheally with purified bacterial exoproducts, delivered alone or in combination, developed pulmonary histopathology similar to that induced by the experimental infection. The results indicate that these exoproducts are produced during the course of the pulmonary infection and suggest that they are involved in the observed lung pathology.