Comparative study of C. difficile antigen/toxin detection in Clostridioides difficile infection

Abstract

Clostridioides difficile (C. difficile) is a major cause of antimicrobial-associated diarrhea/enteritis. However, the sensitivity of EIA and IC methods to detect toxin has been an issue. In this study, we compared the usefulness of Quick Chaser^®CD GDH/TOX (Quick Chaser method) and Smart Gene^®CD Toxin B (SG method). The subjects were C. difficile DNA solutions of known concentrations and 52 patients with suspected CDI. C. difficile DNA solution was serially diluted to confirm the minimum detection limit. The minimum detection limit was 10 copies/μL. Compared to the toxigenic culture method (TC), ①the Quick Chaser method had a sensitivity of 94.4%, specificity of 93.8%, and agreement rate of 94.2% for detection of C. difficile-specific antigen, and 50.0% sensitivity, specificity of 95.8%, and agreement rate of 71.2% for toxin detection. ②The SG method had a sensitivity of 85.7%, specificity of 100.0%, and agreement rate of 92.3% for toxin B gene detection. Since the SG method can be performed using the remainder of the extraction solution from the Quick Chaser method, the two methods can be used together to quickly provide useful information to the clinical side, making them very useful in the treatment of CDI.