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Cell-wall-deficient forms of Staphylococcus aureus as lung pathogens: an ultrastructural study
S Stoitsova1, L Michailova, N Markova
1Institute of Microbiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Abstract:
The interaction between stable protoplast L forms of Staphylococcus aureus and the alveolar wall of infected rats was observed in the course of experimental pulmonary infection (days 3, 7, 14, and 30 p.i.). The L forms were successfully cultivated from bronchoalveolar lavage samples taken throughout the tested interval. The ultrastructural results demonstrated the ability of the L forms to invade the alveolar wall where they established, grew and reproduced mainly in the interstitium. The infection caused lung lesions: granulomas, focal fibroses and destruction of type I alveolar epithelial cells.
Insights
Staphylococcus aureus L forms invade rat lungs, establishing in the interstitium and causing alveolar wall damage. This study details their interaction and the resulting lung lesions over 30 days.
Area of Science:
- Microbiology
- Pathology
- Pulmonary Medicine
Background:
- Staphylococcus aureus can exist in cell-wall-deficient L-form states.
- Understanding L-form interactions in vivo is crucial for infection pathogenesis.
Purpose of the Study:
- To investigate the interaction between Staphylococcus aureus L forms and the rat alveolar wall during experimental pulmonary infection.
- To characterize the ultrastructural changes and lesion development.
Main Methods:
- Experimental pulmonary infection model in rats using Staphylococcus aureus L forms.
- Cultivation of L forms from bronchoalveolar lavage samples at various time points (days 3, 7, 14, 30 p.i.).
- Ultrastructural analysis of lung tissue to observe L-form invasion and host response.
Main Results:
- Staphylococcus aureus L forms were consistently isolated from bronchoalveolar lavage.
- Ultrastructural evidence showed L forms invading and establishing within the alveolar wall interstitium.
- Infection led to lung lesions including granulomas, focal fibroses, and type I alveolar epithelial cell destruction.
Conclusions:
- Staphylococcus aureus L forms actively invade and persist within the lung interstitium.
- These L forms contribute to the pathogenesis of pulmonary lesions and tissue damage.
- The study highlights the significant role of L forms in staphylococcal lung infections.