Xpert c difficile system

Xpert C. difficile system
(Cepheid) is an automated, real-time multiplex PCR assay using disposable cartridge. This assay detects toxin B (tcdB), binary toxin (cdt), and a point mutation associated with PCR ribotype 027. The result of the toxin B target means the presence of toxigenic C. difficile. The results of other targets indicate additional information regarding ribotype 027. The invalid result is reported when sample processing control is failed, indicating that the sample is not properly processed or PCR is inhibited. Using a maximum valid cycle threshold setting of 37 for tcdB, the limit of detection point estimate for toxigenic C. difficile is 1,657 CFU/swab (95% confidence interval [CI], 1,157–3,561 CFU/swab), according to the manufacturer’s insert.

This study was approved by the Institutional Review Board of the Konkuk University Medical Center, Seoul, Korea. This study included 99 fecal samples from patients, which were submitted to our center for laboratory tests. These included 79 tcdB positive samples by real-time PCR (Xpert C. difficile system, Cepheid, Sunnyvale, CA, USA) from March 2017 to October 2017 and the other 20 fecal samples were obtained from healthy controls whose samples were submitted for occult blood test of general health examination (controls). This study required neither study-specific nor any other interventions and the data were analyzed anonymously. Therefore, written informed consent from the enrolled patients was waived by the ethics committee.