Most common cause of Pneumatocele:

Ans. (d) Staphylococcus AureusRef: Harrisons's 19 th ed.* Pulmonary pneumatoceles are thin-walled, air-filled cysts that develop within the lung parenchyma.* They can be single emphysematous lesions but are more, often multiple, thin-walled, air-filled, cystlike cavities.* Pneumatoceles are generally observed soon after the development of pneumonia and can be observed on the initial chest radiograph.* They are commonly caused by Staphylococcus Aureus.* Other agents also causes pneumatocele including:# Streptococcus pneumonia# H. Influenza,# E. Coli# Group A streptococci# Serratia marcescens# Klebsiella pneumoniae, adenovirus, and tuberculosis.* Noninfectious etiologies include hydrocarbon ingestion, trauma, and positive pressure ventilation.