2025 Southeastern Residency Conference

Title: Impact of a Novel Sepsis Diagnostic Test on the Prescribing Habits of Antimicrobials 
Authors: Monica Campbell, Emily Johnston, Hollis O'Neal, Christopher Thomas 
Objective: The objective of this study is to calculate de-escalation timing of antibiotics in septic patients prior to and after the use of a novel sepsis diagnostic test at our institution. 
Background: IntelliSep, an FDA approved rapid diagnostic and risk stratification test for sepsis has been used at Our Lady of the Lake Regional Medical Center (OLOLRMC) since August 2023. This test uses the biophysical abnormalities of leukocytes and associates this with detection of sepsis and the potential for impeding organ dysfunction. The purpose of this study is to examine the utilization of Intellisep to combat another prevalent issue, antimicrobial resistance. This study examines the utilization of IntelliSep on antimicrobial prescribing habits and compares time to appropriate de-escalation of antimicrobials, initiation of antimicrobials, and other relevant outcomes in presumed septic patients pre and post the use of IntelliSep.
Methods: This study is a single-center retrospective chart review. Patients included in the study are adult patients presenting to Our Lady of the Lake who received an IntelliSep Index Score (ISI). Based on the ISI, patients are classified as band 1, 2, or 3, with band one patients having a negative predictive value for sepsis of 97.5% based on previous studies. One hundred and ninety-five patients with ISI scores that were hidden from providers, and their treatment decisions, will be the control group compared to 400 total patients with ISI scores within the next year of initiation at our institution. A predetermined scoring system for classifying antimicrobials and their spectrum of activity will be used. In this scoring system, category one antimicrobials are the most narrow up to category three as the most broad. Category four medications are considered restricted antimicrobials at our institution. The primary outcome is time to de-escalation of antimicrobials based on this scoring system. Secondary outcomes include percent initiation of antimicrobials, total days of antimicrobial therapy, ICU and hospital lengths of stay, positive blood cultures within 72 hours of admission, and in-hospital mortality.
Results: Our primary outcome of time to de-escalation was 43.6 hours pre-intelliSep and 34.3 hours post-intelliSep in the overall category, and 22.8 hours and 22.1 hours for band 1, specifically. Number of patients initiated on antibiotics was 52 (67%) and 81 (41%) for band 1 patients pre and post-IntelliSep, respectively. Patients initiated on a broad-spectrum (3ab) regimen for band 1 were 32 (63%) and 28 (35%) for pre and post-intelliSep, respectively. 
Conclusion: Overall, we did not see a difference in our primary outcome for time to de-escalation of antibiotics. There was a statistically significant difference found in antibiotics started on arrival and patients initiated on a broad-spectrum regimen in our band 1 patients. These results are promising and overall point to a more appropriate usage of antimicrobials after the usage of IntelliSep, a diagnostic and risk stratification test for sepsis.