the incidence of nosocomial toxigenic clostridium difficile associated diarrhea in tehran tertiary medical centers

clostridium difficile is the most common cause of nosocomial diarrhea. it is usually a consequence of antibiotic treatment, but sporadic cases can occur. this study was aimed to determine the frequency of the nosocomial clostridium difficile (c. difficile) associated diarrhea in tehran university of medical sciences hospitals and study of antibacterial susceptibility of isolates. in this study a total of 942 stool samples from patients with nosocomial diarrhea that were hospitalized in imam khomeini hospital, shariati hospital and children clinical center were collected. the samples were cultured on a selective cycloserine cefoxitin fructose agar (ccfa) and incubated in anaerobic conditions, at 37°c for 5 days. isolates were characterized to species level by conventional biochemical tests. bacterial cytotoxicity was assayed on tissue culture (vero). antimicrobial sensitivity of isolated toxigenic c. difficile were investigated by kirby beuer method (disk diffusion). our findings show that, of the total patients, 57 toxigenic c. difficile (6.1%) were isolated. results of statistical analysis show significant differences between the rate of isolated toxigenic c. difficile and age group of patients (p