Phenotypic comparison of Pseudomonas aeruginosa strains isolated from a variety of clinical sites

Abstract

Pseudomonas aeruginosa elaborates a number of extracellular products which have been shown to play a role in the pathogenesis of disease caused by this organism. In this study, we showed that the host environment markedly affects the levels of exoproducts produced. We compared the phenotypes of a number of P. aeruginosa strains obtained from a variety of clinical sources, including burn wounds, skin wounds, urine, cystic fibrosis sputum, acute pneumonia sputum, and blood. The clinical isolates were examined quantitatively for levels of total protease, elastase, phospholipase C, exotoxin A, and exoenzyme S produced in vitro under defined conditions. The exoproduct levels varied significantly, depending on the site of isolation. Elevated levels of elastase were demonstrated in strains isolated from acute lung infections, phospholipase C levels were elevated in urinary tract and blood isolates, exotoxin A levels were elevated in blood isolates, and exoenzyme S levels were increased in acute pneumonia isolates. Isolates from cystic fibrosis sputum produced low amounts of virtually all of the tested exoproducts, particularly as compared with sputum isolates from acute P. aeruginosa lung infections.