P-1629. Reduction in Clostridioides difficile Over-diagnosis Following Suppression of C. difficile Target from Multiplex Molecular Stool Assay in a Pediatric Healthcare System

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Abstract Background Clostridioides difficile testing by polymerase chain reaction (PCR) does not differentiate asymptomatic colonization from infection, and children are frequently colonized with toxigenic strains of C. difficile. Over-diagnosis of C. difficile infections can lead to adverse patient outcomes and poorer quality metrics for hospitals.Figure 1:C. difficile PCR orders following change in GI PCR Panel, Interrupted Time Series Methods In January 2023 our pediatric health system enacted multimodal changes to the electronic ordering of stool tests for C. difficile and other gastrointestinal pathogens. A multiplex PCR test for stool was updated to suppress testing for toxigenic C. difficile. The only remaining method to test for C. difficile by PCR in house was a C. difficile toxin gene specific PCR. Additionally, appropriate clinical criteria with a hard stop were added to the C. difficile PCR order (all of: no laxatives in the past 24 hours, at least 3 liquid stools in the past 24 hours, at least one risk factor for C. difficile infection, and patient at least one year old). If providers still sought C. difficile testing without meeting these criteria, infectious disease specialist approval was required. We analyzed the effect of this intervention using interrupted time series analysis and pre-post aggregate rates from January 2019 through February 2024.Figure 2:C. difficile positive rate following change in GI PCR Panel, Interrupted Time Series Results There were 4426 stool PCR tests performed for C. difficile in the pre-intervention period and 622 in the post-intervention period. The mean (± sd) age of those tested was 7.8 years (± 6.1 years). After the intervention, there was an immediate 61% decrease in C. difficile testing incidence (95% CI [53% - 67%], Figure 1) and 51% decrease in C. difficile diagnosis incidence (95% CI [26% - 67%], Figure 2). There was no significant immediate change or change in slope in the C. difficile antibiotic treatment incidence or HFO C. difficile incidence, but there was a trend towards lower rates of healthcare facility onset C. difficile after the change (aggregate rate 4.13 per 10,000 non-NICU patient-days prior to intervention vs. 3.39 after, P = .28). Conclusion Removing C. difficile from multiplex PCR assays and adding required clinical criteria to the electronic order reduces the number of C. difficile tests and diagnoses in a pediatric health system. Disclosures Laura Filkins, PhD, Avsana Labs: Board Member|Avsana Labs: Stocks/Bonds (Private Company)|Biofire Diagnostics: Grant/Research Support