<prompt> Subdural empyema is most commonly caused by:H influenzaStaphylococcus aureusStreptococcus pneumoniaeE. Coli  <response>: Answer is C Streptococcus pneumoniae: Aerobic and Anaerobic streptococci are the most common aetiological agents for subdural ernphyema. influenzae is the most common causative organism in Children, and not in Adults. Subdural Empyema is a collection of pus in the space between he dura and arachnoid. In most cases a single organism is responsible, but many cultures are sterile because patients are often receiving antimicrobial therapy. The major pathogens include Aerobic and anaerobic Streptococci about 50 Staph about 12-16 Aerobic gram -ye bacilli 3-10 Other anaerobes 5 