Question

Which one of the following organisms causes pneumonia which most commonly results in Pneumatocele?

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

Hint:

Think of the organism famous for necrotizing pneumonia and lung abscess in infants.

Answer 1

The Correct Option is C

Step 1: Recall what a pneumatocele is.
A pneumatocele is a thin walled, air filled cyst that forms within the lung during or after a bout of pneumonia. It develops when infection damages the small airway walls, creating a one-way valve that lets air in but not out, so a cavity slowly balloons up.

Step 2: Recall which organism is famous for causing this.
Staphylococcus aureus pneumonia is well known for causing extensive tissue necrosis and abscess formation in the lung, especially in infants and young children. This necrotizing damage to small airways is exactly the mechanism that produces pneumatoceles, and Staph pneumonia is the classic cause taught for this finding.

Step 3: Compare with the other organisms.
Klebsiella pneumoniae (A) typically causes a necrotizing pneumonia with thick, blood tinged sputum and can lead to lung abscess, but pneumatocele formation is far less characteristic of it than of staphylococcal pneumonia. Haemophilus influenzae (B) causes bronchopneumonia, especially in children, but it is not classically linked with pneumatocele formation. Streptococcus pneumoniae (D) is the most common cause of community acquired pneumonia overall, but it usually resolves without cavity formation and is not the classic cause of pneumatoceles.

Step 4: Final answer.
The organism most commonly linked with pneumatocele formation is
\[ \boxed{\text{Staphylococcus aureus}} \]