Clostridioides difficile infection (CDI) remains a leading cause of healthcare-associated diarrhoea and antibiotic-associated colitis. C. difficile produces 2 types of toxins; toxins A and B (encoded by TcdA & TcdB genes, respectively), which are virulence factors causing cytotoxicity and cellular detachment from intestinal epithelium and are responsible for CDI symptomatology. Many laboratories routinely perform singleplex or multiplex PCR testing, which detects C. difficile toxin genes (tcdA/tcdB) with/ without the detection of the hypervirulent ribotype O27/NAP1/B1 strain.
Local PathCare data confirm a rise in C. difficile detections, with increasing multiplex test positivity rates and a corresponding increase in absolute detection numbers. Although PCR testing is highly sensitive, it cannot distinguish between C. difficile colonisation and true infection driven by toxin production and may remain positive despite successful CDI therapy. In the context of rising C. difficile transmission, this limitation may contribute to overdiagnosis and unnecessary CDI treatment.
Implementation and Benefits of Routine Two-Step Testing