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Published on: March 17, 2014
Cilia-associated respiratory (CAR) bacillus infection of obese mice
J W Griffith1, W J White, P J Danneman
1Department of Comparative Medicine, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey.
Abstract:
Cilia-associated respiratory (CAR) bacillus was identified in respiratory tract lesions of obese mice dying of chronic respiratory disease. Neither Mycoplasma pulmonis nor pathogenic bacteria were isolated from cultures of the lesions at necropsy, but there was serologic and histologic evidence of respiratory virus infection. Cranial-ventral areas of lung were firm and demarcated from unaffected lung at gross examination, and representative tissue sank in water. Microscopically, there was suppurative bronchopneumonia with extensive peribronchiole lymphocyte and plasma cell proliferation. The affected bronchiole epithelium was covered with a sheet of slightly basophilic, filamentous, gram negative bacteria. Bronchioles with lesser amounts of lymphocyte accumulations contained lesser amounts of filamentous bacteria. Bronchioles without filamentous bacteria lining the respiratory epithelium lacked peribronchiole lymphocyte accumulations. There was a high correlation between CAR bacillus-positive serology and the identification of diagnostic histologic lesions. CAR bacillus was readily stained using immunohistochemical methods, and the ultrastructural features were similar to that described in rat infections.
Insights
Cilia-associated respiratory (CAR) bacillus was found in obese mice with chronic respiratory disease. This bacterium is linked to lung lesions and inflammation, suggesting its role in the disease.
Area of Science:
- Veterinary Pathology
- Microbiology
- Immunology
Background:
- Cilia-associated respiratory (CAR) bacillus is a known respiratory pathogen in rodents.
- Obese mice with chronic respiratory disease often present with complex lung pathologies.
- Differential diagnosis of respiratory infections in mice is crucial for accurate research.
Purpose of the Study:
- To identify the causative agent of chronic respiratory disease in obese mice.
- To investigate the association between CAR bacillus and observed lung lesions.
- To characterize the pathological and microbiological findings in affected mice.
Main Methods:
- Necropsy and histopathological examination of lung tissues.
- Bacteriological cultures to rule out other pathogens like Mycoplasma pulmonis.
- Serological testing for CAR bacillus.
- Immunohistochemical staining and ultrastructural analysis of bacteria.
Main Results:
- CAR bacillus was identified in respiratory tract lesions of obese mice.
- Suppurative bronchopneumonia with significant peribronchiolar inflammation was observed.
- A strong correlation was found between CAR bacillus serology and diagnostic histological lesions.
- Filamentous, gram-negative bacteria consistent with CAR bacillus were abundant on bronchiole epithelium.
Conclusions:
- CAR bacillus is implicated in the chronic respiratory disease observed in obese mice.
- Histopathological findings, including inflammation and bacterial presence, are characteristic of CAR bacillus infection.
- Immunohistochemistry and ultrastructural analysis confirm the identification of CAR bacillus.
