Cell-wall-deficient forms of Staphylococcus aureus as lung pathogens: an ultrastructural study

The interaction between stable protoplast L forms of Staphylococcus aureus and the alveolar wall of infected rats was observed in the course of experi mental pulmonary infection (days 3. 7. 14, and 30 p.i.). The L forms were s uccessfully 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 1 alveolar epithelial ce lls.