<prompt> Most common organism, responsible for pseudomembranous colitis is:Clostridium difficileClostridium botulismClostridium bifermentansClostridium histolyticum  <response>: Pseudomembranous colitis refers to swelling or inflammation of the large intestine colon due to an overgrowth of Clostridium difficile C. difficile bacteria. This infection is a common cause of diarrhea after antibiotic use. 