A patient of post-cholecystectomy biliary stricture has undergone an ERCP three days ago. Following this she has developed acute cholangitis. Which of the following is the most likely organism causing acute cholangitis?: (A) Bacillus fragilis, (B) Escherichia coli, (C) Streptococcus viridans, (D) Pseudomonas aeuroginosa
Answer is B. The most common organisms implicated in acute cholangitis are Escherichia coli (27%), Klebsiella species (16%), Enterobacter, Streptococcus viridans (8%), Enterococcus and anaerobes. Ref: CURRENT Diagnosis and Treatment: Gastroenterology, Hepatology and Endoscopy, 2nd Edition, Chapter 32.