P-207. Implementation of Two-Step C. difficile Testing to Reduce HO-CDI and Antibiotic Use with Analysis of Ordering and Treatment Practices
Authors: Phillips Emma C , Manning Brandi , Agnello Sydney , Reed Erica E , Coe Kelci E , Colburn Nora , Day Shandra R 
Published: January 2025

Abstract

Background
C. difficile infection (CDI) is an ongoing challenge for healthcare facilities. The mischaracterization of C. difficile colonization as active infection falsely elevates healthcare onset-CDI (HO-CDI) rates and increases antimicrobial overuse and healthcare costs. Two-step testing for CDI helps differentiate colonization from infection. We describe the change in HO-CDI rates and antimicrobial use following implementation of two-step C. difficile testing with analysis of order and treatment practices post-implementation.Figure 1:HO-CDI Rates Pre and Post-InterventionHO-CDI rates per 10,000 patient days pre and post-intervention. The vertical dotted black line indicates the date of intervention.

Methods
Two-step C. difficile testing (PCR followed by ELISA for toxin if PCR-positive) was implemented Sept. 5, 2023. HO-CDI rates were compared for 6 months pre and post intervention using MedCalc statistical software. Antimicrobial patient days per 1000 patient days for oral vancomycin and fidaxomicin was compared pre and post-intervention using Wilcoxen Rank Sum test. Analysis of all inpatients with a C. difficile order during the post-intervention period was performed including test result, demographics, diarrhea documentation, laxative use, C. difficile treatment and repeat testing.Figure 2:Antimicrobial Patient Days for PO Vancomycin and Fidaxomicin Pre and Post-InterventionAntimicrobial patient days per 1000 pre and post-intervention. The vertical dotted black line indicates the date of intervention.

Results
HO-CDI rates decreased from 6.44 to 2.89/10,000 patient days pre and post-intervention with an incidence rate ratio of 2.22, P&lt; 0.0001 (Figure 1). Inpatient prescriptions for oral vancomycin and fidaxomicin decreased from 28.4 to 22.2 antimicrobial patient days per 1000 patient days, p=0.0295 (Figure 2). A total of 1836 tests were done in the post-intervention period with detailed analysis included in Table 1. Less than 20% of patients had ≥3 diarrhea stools documented and excluding orders on HD 1 or 2, stool documentation was present in 29% of patients. Analysis of the 66 HO-CDI cases was similar compared to all positive cases with 24 (36%) receiving laxatives and 21 (36%) with diarrhea documented.Table 1:Analysis of All Inpatient C. diff Orders Post-InterventionAnalysis of all inpatient C. diff orders post-intervention, where negative indicates PCR negative / toxin negative; discordant indicates PCR positive / toxin negative; and positive indicates PCR positive / toxin positive.

Conclusion
HO-CDI rates and C. difficile specific antimicrobial use were significantly decreased after implementation of two-step testing. Despite this decrease, over half of discordant result patients received C difficile treatment, indicating an opportunity for additional education. Optimization of diagnostic stewardship with regards to laxative use and appropriate stool documentation are areas of opportunity.

Disclosures
All Authors: No reported disclosures