This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Medicine
[{'content': 'Most common cause of epidural abscess - \nSelect and explain. \nA. Staphylococcus, B. Streptococcus, C. Gram negative bacilli, D. Microaerophilic anaerobic streptococci', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Staphylococcuso Therefore spinal epidural abscess is much more common than the intracranial epidural abscess.# Spinal epidural abscess is more common by a factor of nine to one.Causes of epidural abscess", 'role': 'assistant'}]