213 - An Analysis of the Impact of Gastrointestinal Polymerase Chain Reaction Panel Use on Antimicrobial use at a Tertiary Care Academic Medical Center

Background: Gastrointestinal Polymerase Chain Reaction (GI PCR) panels are increasingly utilized in place of conventional stool testing methods. Several studies have noted GI PCR testing is associated with a reduction in antibiotic prescribing. As it relates to the appropriate timing to order this test in hospitalized patients, one study showed decreased utility when ordered more than 72 hours into admission. At Tampa General Hospital, we utilize the BioFire® FilmArray® GI PCR panel. Since implementation in March 2015, its impact on antimicrobial use has not been formally assessed. Our aim was to evaluate the impact of the GI PCR panel and determine its usefulness as a potential tool for antimicrobial stewardship.

Methods: We conducted an IRB approved retrospective chart review in adult patients admitted to our institution who were ordered the GI PCR panel between 1/1/2018 and 12/31/19. Our primary objective was to assess antimicrobial prescribing patterns; secondary objectives included determining the quantity of tests ordered after 72 hours of admission and inpatient length of stay.

Results: Our initial chart review of 50 patients who were ordered the GI PCR panel revealed 60 % (n = 30) females with an overall median age of 55 years (interquartile range (IQR): 40.75,66.75). GI PCRs were ordered a median of 1 day into the hospital admission (IQR: 1,3) with 6 patients having a test ordered longer than 72 hours into their admission. The median length of stay was 5 days (IQR: 3,7). Testing was negative for 82 % of patients. For patients with positive tests, the most common pathogen identified was E coli (EPEC). Five out of 50 patients (10%) had antimicrobial therapy modified after GI PCR results. Internal medicine providers ordered the majority of tests in these patients (n = 26 (52 %)).

Conclusion: Our findings suggest the majority of GI PCRs were ordered within 72 hours of admission. However, changes in antimicrobial therapy were minimal. A limitation of our study includes patients who were on antimicrobials for other indications.