1092. Tuning Down Clostridioides difficile PCR Sensitivity Reduces Treatment for C. difficile Infection in Toxin-Negative Patients With No Increase in Adverse Outcomes

Abstract

BackgroundStudies have shown that toxin detection identifies those who require treatment for C. difficile infection (CDI) and free toxin can be predicted with high negative predictive value from PCR cycle threshold (CT). CT-toxin was introduced at our institution in two phases: from October 2016 to October 2017, CT-toxin was reported with the PCR result (split reporting) and CDI therapy was discouraged if CT-toxin was negative (PCR+/CTtox−). Interim analysis showed that CDI treatment had no effect on outcomes in these CTtox− patients, so starting November 2017, only CT-toxin was reported. Outcomes in PCR+/CTtox− patients treated during split reporting and untreated during the toxin-only period are detailed here.MethodsPatients tested from October 2016 to February. 2018 with a positive Xpert tcdB PCR (Cepheid, Sunnyvale, CA) and CTtox− result were included. Clinical data were collected by retrospective chart review in the split reporting period and prospective review in the toxin-only period and analyzed using SPSS at α = 0.01.ResultsOf 186 unique PCR+/CTtox- patients during split reporting, 99 (53%) were treated, compared with 6 (12%, n = 51) in the toxin-only period (P < 0.001). In comparing treated patients during split reporting to untreated patients during toxin-only reporting (n = 45), there were no significant differences in age, sex, prior antibiotic use, CDI in the previous 6 months, Charlson Comorbidity Index, patient location, immune status, or data at testing, including WBC count, creatinine, albumin, and stools/day. There were no cases of fulminant CDI in either group and no difference in outcomes (table).ConclusionReporting of CT-toxin alone significantly reduced treatment for CDI compared with split reporting in CTtox− patients with no increase in adverse outcomes in short-term follow-up. Further study is needed to confirm these findings in a larger cohort. Table: Outcomes in Patients With PCR+/CTtox− Result by Treatment Status and Reporting Period. Categorical Variables Are Denoted as n (%) and Continuous Variables as Mean [Standard Deviation]OutcomesSplit ReportingTreated (n = 99)CT-Toxin Only ReportingUntreated (n = 45) P-valueDays to diarrhea resolution(<3 stools/day)2.8 [1.9]2.2 [2.1]0.2CTtox+ CDI within 8 weeks8 (8.1)4 (8.9)0.930-Day all-cause mortality9 (9.1)3 (6.7)0.8Disclosures All authors: No reported disclosures.