['clostridium difficile']
['opt-80', 'vancomycin']

        Inclusion Criteria:

          -  Inpatients who have symptoms of CDAD as defined by;

               -  (1)Diarrhea: with ≥4 unformed bowel movements (or ≥200 mL unformed stool for
                  subjects having rectal collection devices) and

               -  (2)Presence of either toxin A and/or B of C. difficile in the stool

          -  Subjects who have not received antibacterials (vancomycin, metronidazole, et.al.)
             aiming at CDAD treatment before the study

        Exclusion Criteria:

          -  Life-threatening or fulminant CDAD

          -  Ileus paralytic or toxic megacolon

          -  Likelihood of death before the completion of study from any cause

          -  Concurrent use of oral vancomycin, metronidazole, et.al. aiming at the treatment of
             CDAD

          -  The anticipated need to continue other antibacterials for a period exceeding seven
             days from providing the informed consent

          -  Subjects who in the opinion of the investigator require other drugs to control
             diarrhea

          -  Need of change in dosage regimen of opiates during the study period

          -  Need of change in dosage regimen of probiotic products during the study period

          -  History/complications of ulcerative colitis or Crohn's disease

          -  Multiple occurrences of CDAD within the past three months

          -  Hypersensitivity to vancomycin

          -  Previous exposure to OPT-80 (fidaxomicin)

          -  Female patients who are pregnant, breastfeeding or possibly pregnant, or wishing to
             become pregnant during the course of study

          -  Participation in other clinical research studies or Post Marketing Clinical Trials
             utilizing an investigational agent within one month prior to providing the informed
             consent or within five half-lives of the investigational agent, whichever is longer
      