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Role of exoenzyme S in chronic Pseudomonas aeruginosa lung infections
Abstract:
Exoenzyme S is an extracellular ADP-ribosyltransferase enzyme produced by Pseudomonas aeruginosa. Mutants of Pseudomonas aeruginosa deficient in this enzyme have been shown to have reduced virulence in infections of burned mice. The contribution of exoenzyme S to the pathogenesis of chronic lung infections with this organism was evaluated by examining the incidence of exoenzyme S production by Pseudomonas aeruginosa strains isolated from cystic fibrosis patients and comparing an exoenzyme S deficient mutant and its exoenzyme S producing parent in a rat chronic lung infection model. Of 51 isolates examined, 43% produced detectable levels of exoenzyme S. While both the exoenzyme S deficient mutant and its parent strain were equally capable of colonizing and persisting in rat lungs, the exoenzyme S producing parent elicited a greater degree of lung damage. These data suggest that exoenzyme S contributes to the pathogenesis of chronic lung infections.
Insights
Pseudomonas aeruginosa
Area of Science:
- Microbiology
- Pathogenesis
- Enzymology
Background:
- Exoenzyme S is an extracellular ADP-ribosyltransferase produced by Pseudomonas aeruginosa.
- Reduced virulence is observed in Pseudomonas aeruginosa mutants lacking exoenzyme S in mouse infection models.
Purpose of the Study:
- To evaluate the role of exoenzyme S in the pathogenesis of chronic Pseudomonas aeruginosa lung infections.
- To determine the incidence of exoenzyme S production in cystic fibrosis patient isolates.
- To compare the virulence of exoenzyme S-deficient mutants and their parent strains in a rat chronic lung infection model.
Main Methods:
- Analysis of Pseudomonas aeruginosa strains from cystic fibrosis patients for exoenzyme S production.
- Infection of a rat chronic lung model with an exoenzyme S-deficient mutant and its parent strain.
Main Results:
- 43% of 51 Pseudomonas aeruginosa isolates from cystic fibrosis patients produced detectable exoenzyme S.
- Both exoenzyme S-deficient mutants and parent strains equally colonized and persisted in rat lungs.
- The exoenzyme S-producing parent strain caused significantly greater lung damage compared to the mutant.
Conclusions:
- Exoenzyme S contributes to the pathogenesis of chronic Pseudomonas aeruginosa lung infections.
- The enzyme plays a role in the severity of lung damage during chronic infections.