Immunoenzymometric assays for alkaline protease and exotoxin A from Pseudomonas aeruginosa: development and use in detecting exoproteins in clinical isolates from patients with cystic fibrosis.

Using immunoenzymometric assays, the production of elastase, alkaline protease and exotoxin A was determined in culture supernatants of 35 strains of Pseudomonas aeruginosa isolated from patients suffering from cystic fibrosis. The assays were simple, specific, sensitive and reproducible, and permitted the determination of low levels of exoproteins. A large strain variability of exoprotein production was found. Most of the strains secreted all three exoproteins, but six out of the 35 strains (17%) did not secrete at least one of the three (< 0.3 microgram/l). A significant correlation was observed between elastase and exotoxin A productions (r = 0.697, p < 0.001).