This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
Malignant otitis externa is caused by 
Select and explain. 
A. Hemophilus influenzae, B. Pseudomonas aeroginosa, C. Streptococcus pyogenes, D. E. coli
B: Pseudomonas aeroginosa
Answer: B: Pseudomonas aeroginosa 
Explanation: Malignant otitis externa is often caused by difficult to treat bacteria such as Pseudomonas aeruginosa. Only are cases of malignant otitis externa due to S.aureus, Proteus mirabilis and Aspergillus fumigates have been repoed.Ref: PL Dhingra, Diseases of Ear, Nose & Throat, 7th edition, pg no. 55