Rapid Multiplex Gastrointestinal Pathogen Panel Testing Improves Antibiotic Stewardship in Patients with Suspected Infectious Diarrhea Compared with Conventional Methods

BACKGROUND: The BioFire FilmArray™ Gastrointestinal (GI) Panel is a 1 hour multiplex real-time PCR test that can detect the presence of 22 GI pathogens (viral, bacterial, and parasitic) known to cause infectious diarrhea. Our tertiary-care academic medical center implemented the GI Panel for all cases of suspected infectious diarrhea replacing the previous conventional testing once utilized to detect GI pathogens. METHODS: The aim of this IRB approved, retrospective investigation was to determine the utility of the GI panel testing vs. the conventional testing to guide patient management. Cases were randomly selected, stratified by age group and result (specific pathogens or negative result) in the pre-implementation period (n = 119 of 1550 samples) from May 2014 through April 2015 and in the post-implementation period (n = 333 of 1117 samples) from May 2015 through April 2016. RESULTS: The rate of a positive test for any stool pathogen per patient was 34.2% (n = 342 of 999) for the GI panel and 11.6% (n = 162 of 1391) for conventional testing, P = <0.0001. Median time to test result from collection was 3.3 hours for the GI panel vs 45.4 hours for culture (P < 0.0001). Among patients started on antibiotics prior to result, discontinuation rate was 33% (n = 30/90) after GI panel results vs 5.4% (n = 2/37) after stool culture results, P = 0.0014. Antibiotics were initiated or adjusted after the result in 28.5% of patients (95/333) in the GI panel cohort compared with 60.5% (72/119) in the culture cohort; however, this was influenced by the method for selecting cases and the higher yield of viral pathogens in the GI Panel cohort. Mean time to antibiotic adjustment was 2.1 hours with the GI panel vs 22.0 hours in the culture cohort (P = 0.0155). Appropriateness of antibiotic use, adjudicated after the test result became available was significantly higher in the GI panel group (91%), compared with the culture group (81%), P < 0.0039. CONCLUSION: After implementation of a rapid multiplex GI pathogen panel to evaluate stool samples from patients with suspected infectious diarrhea, our institution saw benefits in antibiotic stewardship, including: higher diagnostic yield, faster results, higher rates of antibiotic discontinuation, shorter time to antibiotic adjustment and a lower rate of inappropriate antibiotic treatment. DISCLOSURES: All authors: No reported disclosures.