This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
[{'content': 'In cholangitis, the organism mostly responsible is \nSelect and explain. \nA. E.coli, B. Streptococcus, C. E.histolytica, D. Clostridium', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ascending bacterial infection of the biliary ductal system with obstruction Most common cause is choledocholithiasis Most common organisms present in the bile in patients with cholangitis : E.coli (MC). Klebsiella pneumoniae, streptococcus faecalis & Bacteroides fragilis Ref: Sabiston 20th edition Pgno :1507', 'role': 'assistant'}]