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Infection in vitro of the human pulmonary macrophage with Staphylococcus aureus (bacteriologic and ultrastructural
Abstract:
Alveolar macrophages from exeresis fragments taken from patients operated for pulmonary cancer were infected in vitro with Staphylococcus aureus. Part of the investigation was carried out in the presence of an antibiotic (pyopen) introduced in the culture medium. Bacteriologic seeding from an extracellular medium and from lyzed cells showed a greater intracellular multiplication rate. In the presence of pyopen there was a decrease in the number of germs due to the inhibition of multiplication. Electron microscopy revealed reduced phagolysosomal fusion, aspects of bacterial multiplication and the coexistence of intact bacteria and bacteria presenting structural alterations. The results suggest the importance of cellular parasitism in the chronic evolution of infectious bronchopulmonary processes.
Insights
Staphylococcus aureus multiplies within alveolar macrophages, suggesting a role in chronic lung infections. An antibiotic, pyopen, reduced bacterial numbers by inhibiting this intracellular growth.
Area of Science:
- Pulmonary Medicine
- Microbiology
- Cell Biology
Background:
- Alveolar macrophages are crucial for lung immunity.
- Staphylococcus aureus is a common cause of bacterial pneumonia.
- Intracellular bacterial growth can complicate treatment.
Purpose of the Study:
- To investigate Staphylococcus aureus intracellular multiplication within human alveolar macrophages.
- To assess the effect of the antibiotic pyopen on intracellular bacterial growth.
- To explore the mechanisms of bacterial survival and host cell interaction.
Main Methods:
- In vitro infection of human alveolar macrophages with Staphylococcus aureus.
- Bacteriologic seeding of extracellular and intracellular bacteria.
- Treatment with the antibiotic pyopen.
- Electron microscopy for ultrastructural analysis.
Main Results:
- Staphylococcus aureus exhibited significant intracellular multiplication within alveolar macrophages.
- Pyopen treatment decreased bacterial load by inhibiting intracellular multiplication.
- Electron microscopy showed reduced phagolysosomal fusion and bacterial structural alterations.
Conclusions:
- Alveolar macrophages support Staphylococcus aureus intracellular proliferation.
- Antibiotic inhibition of intracellular growth is a key factor in controlling infection.
- Cellular parasitism by S. aureus is important in chronic bronchopulmonary infections.