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Assessment of elastase as a Pseudomonas aeruginosa virulence factor in experimental lung infection in mink
L E Elsheikh1, T Kronevi, B Wretlind
1National Veterinary Institute, Uppsala, Sweden.
Abstract:
Anaesthetized mink were inoculated intratracheally with an elastase-producing Pseudomonas aeruginosa strain (PAO1) and two mutants derived from PAO1 with defective elastase formation (strains PAO1-E64 and PAO1-las-16). Survival times were prolonged in mink infected with the mutants, and microscopic examination of lungs showed that the elastase-positive wild type strain produced more pronounced tissue damage and haemorrhages than did the elastase-defective mutant strains. The strains PAO1 and PAO1-las-16 were also compared to three strains isolated from natural infection in mink which differed in elastase production. The mink strains with high or moderate elastase production produced more severe lung damage and were associated with a higher mortality than the other strains tested. The results indicate that P. aeruginosa may enhance the virulence of the bacterium in lung infections.
Insights
Pseudomonas aeruginosa elastase contributes to lung damage and mortality in mink. Elastase-defective strains caused less severe infections, indicating elastase enhances bacterial virulence in respiratory infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Veterinary Pathology
Background:
- Pseudomonas aeruginosa is an opportunistic pathogen causing various infections.
- Bacterial elastase is a key virulence factor in P. aeruginosa infections.
- The role of P. aeruginosa elastase in mink lung infections requires further investigation.
Purpose of the Study:
- To evaluate the role of Pseudomonas aeruginosa elastase in the pathogenesis of lung infections in mink.
- To compare the virulence of wild-type P. aeruginosa with elastase-defective mutants in a mink model.
- To assess the impact of elastase production by naturally occurring P. aeruginosa strains on disease severity in mink.
Main Methods:
- Intratracheal inoculation of mink with P. aeruginosa strains (wild-type and elastase-defective mutants).
- Monitoring of survival times and clinical signs in infected mink.
- Histopathological examination of lung tissues to assess tissue damage and inflammation.
- Comparison with naturally isolated P. aeruginosa strains exhibiting varying elastase production.
Main Results:
- Elastase-defective P. aeruginosa mutants resulted in prolonged survival times and reduced lung tissue damage compared to the wild-type strain.
- Wild-type P. aeruginosa strains with high or moderate elastase production caused more severe lung damage, hemorrhages, and higher mortality.
- Naturally isolated strains with higher elastase activity were associated with more pronounced disease severity.
Conclusions:
- Pseudomonas aeruginosa elastase is a significant virulence factor contributing to the severity of lung infections in mink.
- Elastase production by P. aeruginosa enhances bacterial virulence and pathogenicity in respiratory infections.
- These findings highlight the importance of elastase in P. aeruginosa-induced lung pathology and suggest potential therapeutic targets.