The major cause of pseudomembranous colitis is known to be Clostridium difficile (C. difficile). There are few reports that Clostridium species other than C. difficile has caused pseudomembranous colitis. We report a case of pseudomembranous colitis caused by Clostridium glycolicum (C. glycolicum).

A 47-year-old woman who had operational history for rectal cancer 3 months ago, was readmitted with diarrhea of 3 days duration. Seven weeks before admission, she had received ornidazole and ceftriaxone due to diarrhea and abdominal pain, and her symptoms were improved. She had received additional radiation therapy for rectal cancer during six weeks before the recent onset of diarrhea. On admission, she complained of watery diarrhea ten times a day and abdominal pain. She had tenderness on both lower abdomen. Pseudomembrane was observed by colonoscopic and histologic examination. VIDAS C. difficile toxin A II assay was positive and C. glycolicum was isolated in the stool. She recovered after receiving oral metronidazole treatment.