Towards better severity stratification in Clostridioides difficile infection: bridging the gap between surveillance...

Accurate and consistent documentation of severe Clostridioides difficile infection (sCDI) is essential for risk stratification, timely management and optimal resource allocation. This study aimed to evaluate and compare the application of national surveillance criteria and European Society for Clinical Microbiology and Infectious Diseases (ESCMID) treatment-based definitions of sCDI to identify opportunities for improvement in severity classification and case identification.

A retrospective review was conducted of all CDI episodes between 6^th January 2023 and 6^th January 2024 in an Irish tertiary hospital. Data included patient demographics, recent antimicrobial exposures, ribotype and sequence type (ST), radiology and clinical outcomes. Episodes were categorised as sCDI using both the Irish national surveillance sCDI definition and ESCMID treatment-based criteria for sCDI and severe-complicated Clostridioides difficile infection (sc-CDI).

Among 140 CDI episodes in 131 patients, 100 (71%) were healthcare-associated and 122 (93%) had recent antimicrobial exposure. While only two episodes (1.4%) met national sCDI surveillance criteria, 63 (45%) met ESCMID sCDI and 19 (13.5%) met ESCMID sc-CDI criteria. Among ESCMID-defined sCDI cases, 39 (62%) met only one criterion, suggesting potential overestimation of severity. Sequence types ST11 and ST10 were more frequent in severe cases.

Current surveillance definitions may underestimate, while treatment-based criteria may overestimate the burden of sCDI. A revised, clinically balanced sCDI case definition is required to enhance severity stratification, improve case detection and guide appropriate allocation of healthcare resources.