Rapid and accurate diagnosis of Clostridium difficile infection by real-time polymerase chain reaction

Background/Aims: The incidence and severity of Clostridium difficile infection (CDI) have increased worldwide, resulting in a need for rapid and accurate diagnostic methods. Methods: A retrospective study was conducted to compare CDI diagnosis methods between January 2014 and December 2014. The stool samples, which were obtained in presumptive CDI patients, were compared for their diagnostic accuracy and rapidity, including real-time polymerase chain reaction (PCR) of toxin genes, C. difficile toxin assay, and culture for C. difficile. Results: A total of 207 cases from 116 patients were enrolled in this study and 117 cases (56.5%) were diagnosed as having CDI. Among the 117 cases, the sensitivities of real-time PCR, C. difficile toxin assay, and culture for C. difficile were 87.2% (102 cases; 95% CI, 80.7%-92.8%), 48.7% (57 cases; 95% CI, 41.0%-59.8%), and 65.0% (76 cases; 95% CI, 60.2%-78.5%), respectively (P<0.005). Notably, 34 cases (29.0%) were diagnosed with CDI by real-time PCR only. The time required to obtain results was 2.27 hours (136.62 +/- 82.51 minutes) for real-time PCR, 83.67 hours (5,020.66 +/- 3,816.38 minutes) for toxin assay, and 105.79 hours (6,347.68 +/- 3,331.46 minutes) for culture (P<0.005), respectively. Conclusions: We confirmed that real-time PCR of toxin genes is the most effective diagnostic method for accurate and early diagnosis of CDI. It also helps to diagnose hypervirulent CDI, such as ribotype 027 infection.