This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection of Bones & Joints, Subject name: Orthopaedics
Most common organism causing osteomyelitis: 
Select and explain. 
A. Staph Aureus, B. Strep pneumonia, C. H. Influenza, D. E. coli
A: Staph Aureus
Answer: A: Staph Aureus 
Explanation: Ans. (a) Staph AureusRef: Maheshwari 5th ed. /168Note that responsible pathogens may be isolated in only 35- 40% of infections. Bacterial causes of acute hematogenous and direct osteomyelitis include the following:* Most common organism causing acute osteomyelitis: Staph. Aureus* MCC of osteomyelitis in sickle cell anemia patient: SALMONELLA* MCC of osteomyelitis in IV drug abuser: PSEUDOMONAS* MC organism causing osteomyelitis in open foot injury: PSEUDOMONAS* MC organism causing osteomyelitis in HIV patient: Staph. Aureus* MC organism causing osteomyelitis in case of animal bite: Pasteurella Multiocida* MC organism causing osteomyelitis in case of human bite: Eikenella Corrodens