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: Microbiology
Most common cause of non gonococcal septic ahritis is ? 
Select and explain. 
A. Staph aureus, B. H. influenzae, C. Streptococcus pyogenes, D. Pneumococcus
A: Staph aureus
Answer: A: Staph aureus 
Explanation: Ans. is 'a' i.e., Staph aureusStaphylococcus aureus is the most common cause of septic ahritis in all ages although group-B streptococcus is also a common cause in newborns.H. influenzae was a common cause of septic ahritis in children but has now become rare due to the routine use of the conjugate vaccine. In young sexually active adolescents and adults two bacteria are commonly implicated.Staph aureus (non-gonococcal septic ahritis)Neisseria gonorrheae (vonococcal septic ahritis).