随着抗菌药物的广泛应用,抗生素相关性腹泻(antibiotic-associated diarrhea,AAD)日益受到关注.3%~29%的住院患者在接受抗生素治疗后出现腹泻.难辨梭菌相关性疾病(clostridium difficile-associated disease,CDAD)的病死率为6%~30%.