2366. PCR Followed by Toxin EIA for the Diagnosis of C. difficile Infection

Abstract

BackgroundIn June 2017 for the diagnosis of Clostridioides difficile infection (CDI), Renown Health transitioned from utilizing polymerase chain reaction (PCR) to a two-step algorithm of PCR followed by toxin enzyme immunoassay (EIA) if PCR was positive. Providers were encouraged to forgo treatment in patients that were PCR-positive and EIA-negative as recent literature suggests this may indicate colonization rather than infection. The purpose of this study was to assess the impact of implementation of the two-step algorithm for the diagnosis of CDI on antibiotic usage and patient outcomes.MethodsThis was a retrospective quasi-experimental study of adult inpatients at Renown Regional and South Meadows Medical Centers that were PCR positive before and after implementation of a two-step algorithm for the diagnosis of CDI. The pre-implementation period was defined between May 8, 2016 and May 7, 2017, and the post-implementation period was May 8, 2017 to May 7, 2018. Patients were excluded if they were admitted to a pediatric ward, tested for CDI at an outside facility, or if results were available following discharge. The primary outcome was inpatient days of metronidazole and non-parenteral vancomycin per PCR positive patient. Secondary outcomes included defined daily doses of therapy, proportion of untreated patients, time to resolution of diarrhea, all-cause in-hospital mortality, 30-day recurrence, all-cause 30-day readmission, length of stay, and 30-day CDI-related complications. CDI-related complication was a composite of ICU care, megacolon, ileus, surgical intervention. It was calculated that 242 patients were required to achieve at least 80% power to detect a 30% difference in antibiotic days between pre- and post-implementation of two-step C. difficile testing. Wilcoxon two-sample test was used for continuous data, and χ 2 or Fisher exact test were used for categorical data.ResultsSee figures.ConclusionIncorporation of C. difficile toxin EIA to PCR for the diagnosis of CDI resulted in a significant reduction in non-parenteral vancomycin and metronidazole days of therapy. Patient outcomes were not adversely affected by the addition of toxin EIA. The results suggests that toxin EIA may help differentiate between C. difficile colonization and active infection. Disclosures All authors: No reported disclosures.