Use of transposon mutants to assess the role of exoenzyme S in chronic pulmonary disease due to Pseudomonas aeruginosa.

Among the potential virulence factors produced by Pseudomonas aeruginosa there are two distinct ADP-ribosyl transferases, exotoxin A and exoenzyme S. The role of exoenzyme S in Pseudomonas aeruginosa infection was studied using the rat chronic pulmonary infection model. Pseudomonas aeruginosa strain DG1 and an isogenic mutant of DG1 differing only in its capacity to produce exoenzyme S were employed in the study. Both Pseudomonas aeruginosa strains tested established a chronic pulmonary infection in this model and organisms recovered from lung homogenates were phenotypically unaltered with respect to exoenzyme S production in vitro. The extent of the observed pathology was markedly greater with the strain producing exoenzyme S, indicating that exoenzyme S may play a role in the progressive pathology observed in chronic lung disease due to Pseudomonas aeruginosa.