Pneumatocele formation is most commonly associated with pneumonia caused by which organism?

• A. Staphylococcus aureus
• B. Streptococcus pneumoniae
• C. Pseudomonas aeruginosa
• D. Haemophilus influenzae

Answer: (A)

Pneumatocele formation reflects necrotizing pneumonia where alveolar walls are damaged and air-filled cavities form within the lung parenchyma. Staphylococcus aureus is classically associated with this pattern, especially in children and after influenza, because it readily causes necrosis and abscess-like cavities that develop into thin-walled air spaces seen as pneumatoceles on imaging. These lesions are often multiple and may resolve over weeks, though rupture can lead to pneumothorax. Other organisms can cause pneumonia with different radiographic patterns, but the association with pneumatoceles is most characteristic for Staph aureus.