Using routine asymptomatic Clostridioides difficile testing to identify patients at high risk of developing C. difficile infection during hematopoietic cell transplantation.

Background: Colonization with enteropathogens such as Clostridioides difficile has been linked to clinical infection with these same organisms. C. difficile infection (CDI) is associated with increased morbidity and mortality in patients undergoing hematopoietic cell transplantation (HCT). The study aims to evaluate the utility of existing C. difficile stool detection methods used during pre-transplant planning to identify individuals at high risk of developing CDI within 3 months post-transplant. Methods: A prospective cohort study of patients undergoing HCT at a large quaternary care centre was conducted to assess the impact of baseline C. difficile colonization on downstream CDI outcomes. Baseline stool samples were collected prior to admission for conditioning chemotherapy, which were evaluated for C. difficile colonization using routine, short-turnaround-time clinical approaches by performing glutamine dehydrogenase (GDH) enzyme immunoassay (EIA) and toxin B gene (tcdB) polymerase chain reaction (PCR). Clinical data and outcomes were reviewed 3 months post-transplant. Test characteristics for using baseline C. difficile colonization as a screening tool for predicting subsequent CDI were calculated. Results: Sixty patients were enrolled. The prevalence of C. difficile colonization (GDH positive) among patients undergoing HCT was 10% (6/60). Ten patients developed CDI within 3 months post-transplant, 50% of whom were colonized at baseline. Among the colonized patients, 83% (5/6) developed CDI during the follow-up period. Asymptomatic C. difficile colonization pre-admission had a 98% specificity (95% CI 89% to 100%), 50% sensitivity (95% CI 19% to 81%), 83% positive predictive value (95% CI 36% to 100%), and 91% negative predictive value (95% CI 80% to 97%) for developing subsequent CDI. Conclusions: Pre-admission C. difficile screening could support targeted prophylactic strategies for patients at risk of developing CDI, and this approach warrants further evaluation.