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A mouse model of chronic pulmonary infection with Pseudomonas aeruginosa and Pseudomonas cepacia
J R Starke1, M S Edwards, C Langston
1Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030.
Abstract:
A mouse model of chronic pulmonary infection with either Pseudomonas aeruginosa or Pseudomonas cepacia was developed to compare bacteriologic and pathologic features of these infections. Experimental pneumonia was established in Swiss mice by transoral intratracheal inoculation of 10(3)-10(4) colony-forming units of mucoid P. aeruginosa or P. cepacia enmeshed in agarose beads. Unilateral infection with either strain was tolerated without morbidity. By 10 days postinoculation, the mean colony-forming units per infected lung was 3.8 X 10(5) for P. aeruginosa and 1.0 X 10(5) for P. cepacia. Bacterial counts remained stable through 21 days with no significant difference between organisms. Acute and chronic inflammatory histopathologic changes similar to many found in the lungs of cystic fibrosis patients were present in 95% of lung specimens. The changes occurred with both organisms but were more extensive with mucoid P. aeruginosa. This model represents an important tool for study of the contribution of complement, antibody, and adoptive transfer of T cell-mediated immunity to the pathogenesis of chronic pneumonia with Pseudomonas species, and represents the first successful model of chronic pulmonary infection with P. cepacia.
Insights
This study developed a mouse model for chronic pulmonary Pseudomonas infections. The model revealed similar bacterial loads and lung inflammation for both Pseudomonas aeruginosa and Pseudomonas cepacia, with P. aeruginosa causing more extensive changes.
Area of Science:
- Pulmonary medicine
- Microbiology
- Immunology
Background:
- Chronic pulmonary infections with Pseudomonas species are common in cystic fibrosis patients.
- Understanding the pathogenesis of these infections is crucial for developing effective treatments.
Purpose of the Study:
- To develop and characterize a mouse model of chronic pulmonary infection with Pseudomonas aeruginosa and Pseudomonas cepacia.
- To compare the bacteriologic and pathologic features of these infections in a controlled experimental setting.
Main Methods:
- Swiss mice were inoculated intratracheally with mucoid Pseudomonas aeruginosa or Pseudomonas cepacia.
- Bacterial counts and histopathologic changes were assessed at various time points post-inoculation.
Main Results:
- Both Pseudomonas species established chronic pulmonary infections with stable bacterial loads over 21 days.
- Histopathologic examination revealed acute and chronic inflammation in 95% of lung specimens, similar to cystic fibrosis lung pathology.
- Inflammatory changes were more extensive with Pseudomonas aeruginosa compared to Pseudomonas cepacia.
Conclusions:
- This mouse model is a valuable tool for studying the pathogenesis of chronic Pseudomonas pulmonary infections.
- The model allows for investigation of immune responses, including complement, antibody, and T cell-mediated immunity.
- This represents the first successful mouse model for chronic pulmonary infection with Pseudomonas cepacia.