P-225. Effect of isolating Clostridioides difficile asymptomatic carriers on the incidence of healthcare-associated C. difficile infections: a systematic review and meta-analysis
Authors: Zanichelli Veronica , Wong Jacqueline , Sohani Zahra , Daneman Nick , Frenette Charles , Lee Todd C , Mertz Dominik , McDonald Emily , Brown Kevin , Grant Jennifer M , Haraoui Louis-Patrick , Johnstone Jennie , Katz Kevin , Lee Robyn S , Leis Jerome A , Sander Beate , Wong Titus , Loo Vivian , Longtin Yves 
Published: January 2025

Abstract

Background
Asymptomatic carriers are a potential source of healthcare-associated Clostridioides difficile infection (HA-CDI). Our objective was to investigate the impact of interventions to detect and isolate asymptomatic carriers during their hospital stay on the incidence of HA-CDI.Figure 1Forest plot of the association between screening and isolating C. difficile carriers on admission and HA-CDI (by random-effects meta-analysis)

Methods
We performed a systematic review and searched the research literature up to March 2023 for interventional studies where asymptomatic adult patients were screened for C. difficile colonization and were isolated if positive. Only studies that allocated interventions to clusters of individuals and measured outcomes at the population level were eligible. HA-CDI incidence rate ratios were pooled through random effects meta-analysis. Risk of bias was assessed using the Cochrane’s tool for non-randomized studies of interventions.Figure 2Forest plot of the association between screening and isolating C. difficile carriers on admission to hospital or to selected units and HA-CDI (by random-effects meta-analysis)

Results
5,681 unique references were screened of which six were eligible. All studies were before-after quasi-experimental interventional studies (2/6 included a control group and 4/6 compared incidence rates during the intervention to before) from high-income countries published between 2016 and 2020 that assessed the effects of hospital-wide or unit-wide screening. Two studies only screened patients at high risk of CDI (e.g. hematologic patients receiving chemotherapy). Four studies were considered to have a serious risk of bias. Among the six included studies, 75,870 patients were screened and 4,104 patients were identified as carriers (the proportion of carriers ranged from 3.1 to 15%). Using a random-effects inverse-variance meta-analysis, screening and isolation of carriers was associated with a significant reduction in the incidence of HA-CDI (N=6, pooled rate ratio 0.28, 95% CI 0.20-0.39). Subgroup analyses yielded similar point estimates for reduction in HA-CDI rates both when screening was done on hospital admission (N=3, RR 0.47, 95% CI 0.24 to 0.94) and on admission to specific hospital units (N=3, RR 0.24, 95% CI 0.16 to 0.34).

Conclusion
Based on this systematic review and meta-analysis, screening and isolating C. difficile carriers is associated with a decreased incidence of HA-CDI in adult patients. Due to methodological limitations, robust randomized controlled trials are needed to confirm this finding.

Disclosures
Dominik Mertz, MD, MSc, KCI Inc. USA: Grant/Research Support