Pseudomonas aeruginosa strains obtained from patients with tracheal, urinary tract and wound infection: variations in virulence factors and virulence genes.

Pseudomonas aeruginosa produces several virulence factors including exotoxin A, exoenzyme S and elastase. In previous reports we have analysed several clinical isolates for the production of these three virulence factors and for possible heterogeneity within the genes that code for these factors (toxA, lasB and the exoS genes). The isolates were obtained from three specific sites (trachea, urinary tract and wounds). Although the isolates produced variable levels of these factors, isolates that were obtained specifically from urinary tract and wound infections produced increased levels of exotoxin A and exoenzyme S. In addition, a prolonged infection with P. aeruginosa appears to enhance exoenzyme S production. Restriction site polymorphism was very limited within the toxA, lasB, and exoS structural genes; however, the upstream region of toxA showed restriction site polymorphisms between the different isolates. The observed polymorphisms did not correlate with any variations in the levels of the virulence factors. In this article, we provide a short review of these studies.