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: Surgery
The commonest organism seen in peritonitis is - 
Select and explain. 
A. Escherichia coli, B. Clostridium welchii, C. Staphylococci, D. Klebsiella
A: Escherichia coli
Answer: A: Escherichia coli 
Explanation: Ans. is 'a' i.e., Escherichia coli