Polymerase chain reaction for identification and typing of Clostridium difficile isolated from Chinese patients

Objective: Toxigenic Clostridium difficile, the etiologic agent of C. difficile-associated diarrhea (CDAD), is the most common cause of hospital- acquired diarrhea in many developed countries. In spite of the endemic nature of diarrhea in China, few reports of C. difficile infection in this country have been documented in the literature. Methods: In this study, a polymerase chain reaction (PCR) assay was used to determine the presence of toxigenic C. difficile in the stools of 19 patients who developed diarrhea after antibiotic use in a hospital in China. Clostridium difficile was also cultured from the stool of these patients. After DNA extraction, PCR was performed with primers targeting C. difficile toxin A and toxin B gene sequences. Results: Toxin sequences were detected in 5 of 19 (26%) specimens analyzed. To determine strain identity, these isolates were genotyped using arbitrarily primed PCR (AP-PCR). Three AP-PCR profiles were identified among these isolates. Three of these isolates had the same DNA bending pattern, and they were isolated from patients who were at the same institution. Conclusions: These preliminary results indicate that C. difficile may be involved in some diarrhea cases in China. This study may aid in the understanding of the nature of endemic diarrhea in this country.