This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Orthopaedics
Most common cause of chronic osteomyelitis 
Select and explain. 
A. Staphylococcus aureus, B. Streptococcus pyogenes, C. Mycobacterium tuberculosis, D. Staphylococcus epidermidis
A: Staphylococcus aureus
Answer: A: Staphylococcus aureus 
Explanation: Chronic osteomyelitis is nearly always a sequel to acute osteomyelitisOccasionally infection is subacute or chronic from the beginningAs with acute osteomyelitis, the most common causative organism is staphylococcus areus(Refer: Mohindra's Fundamentals of Ohopedics, 2nd edition, pg no. 283, 284)