This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Most common organism cultured in CSOM is ? 
Select and explain. 
A. Staphylococcus aureus, B. Staphylococcus epidermidis, C. Streptococcus pneumonia, D. Pseudomonas aeruginosa
D: Pseudomonas aeruginosa
Answer: D: Pseudomonas aeruginosa 
Explanation: Ans. is 'd' i.e., Pseudomonas aeruginosa Microbiology of CSOM Pus culture in both types of aerobic and anaerobic CSOM may show multiple organisms. Most commonly isolated organisms are gram negative bacilli, i.e., Pseudomonas, proteus, E.coli. These organisms are not commonly found in the respiratory tract, while commonly found in the skin of external ear.