<prompt> Pneumatocele is commonly caused by:Streptococcus pneumoniaHaemophilus influenzaSerratia marcescensKlebsiella pneumonia  <response>: Ans. a Streptococcus pneumonia Pneumatocoele often occur as a sequela to acute pneumonia, commonly caused by Staphylococcus aureus. 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. Also occur with other agents, including Streptococcus pneumoniae, Haemophilus influenzae, Escherichia coli, group Astreptococci, Serratia marcescens, Klebsiella pneumoniae, adenovirus, and tuberculosis Pneumatocele formation is associated with hyperimmunoglobulin E IgE syndrome Buckley- Job syndrome. 