A study of usefulness of fecal microbiota transplantation for refractory Clostridium difficile infection

INTERVENTION: infusion of solusion of donor feces to recipient's intestine. CONDITION: Reccurent Clostridium difficile infection PRIMARY OUTCOME: Relapse rate of C. difficile infection within 10 weeks after FMT. SECONDARY OUTCOME: change of diarrhea,disappearance of CD toxin,change of intestinal flora,relationship between donar and recipient intestinal flora,adverse event,relapse rate within 6 months. INCLUSION CRITERIA: Recurrent C. difficile infection even with enough treatment, i.e. vancomycin or metronidazole for more than 10 days.