1986. Impact of Two-Step Testing on the Diagnosis and Management of Clostridium difficile in a Multi-Hospital Healthcare System

Abstract Background Distinguishing active C. difficile infection (CDI) from asymptomatic colonization remains a significant challenge. A multi-step testing algorithm can improve the diagnostic accuracy of CDI and associated antibacterial prescribing. This study evaluated the impact of two-step testing on CDI rates and management in a multi-hospital community health system. Methods Two-step C. difficile testing (PCR for initial screening followed by EIA for toxin detection) was implemented in 6 acute care community hospitals in April 2018. EIA testing was automatically performed on all stool samples with a positive C. difficile PCR result. Prior to implementation, PCR alone was used to identify CDI. Messaging attached to the PCR laboratory report alerted prescribers of discrepant results (PCR +/EIA -). Anti-C. difficile therapy was at the discretion of the prescriber. We performed a retrospective cohort analysis over a 2-year period to evaluate the effect of two-step testing on system-wide hospital-onset CDI (HO-CDI) per 10,000 patient-days (PD) and anti-CDI antimicrobial use (AU) in days of therapy (DOT) per 1,000 PD. Segmented negative binomial regression with hospital clustering was used to estimate predicted HO-CDI rate for the baseline period between April 1, 2017 through March 31, 2018 and the post-intervention between May 1, 2018 through March 31, 2019. The implementation date at all sites in April 2018 was unknown; therefore, this month was removed from the analysis. Anti-CDI agents included fidaxomicin, metronidazole, and oral vancomycin, but may have included non-CDI indications for metronidazole. Results A total of 115 HO-CDI cases were identified; 91 (79%) before and 24 (21%) after. Prior to implementation of two-step testing, CDI rates declined at 4% per month (P = NS). The rate immediately dropped by 36% (P = 0.004) after two-step testing was implemented, but the trend did not significantly change (P = 0.52, Figure 1). Community-onset CDI rates also decreased during this time period. Combined facility-wide anti-CDI agent use was 824.87 before and 838.21 DOT/1,000 PD after and did not significantly change. Conclusion Use of a two-step approach for CDI testing reduced HO-CDI rates, but did not have a significant impact on anti-CDI antibiotic use in a multi-hospital community health system. Disclosures All authors: No reported disclosures.