Retrospective Review of BioFireʼs FilmArray Gastrointestinal Panelʼs Detection of Multiple Pathogens in Adults Patients: A Hypothesis Generating Study: 2017 Presidential Poster Award

Abstract

Introduction: Multiplex stool PCR gives clinicians an accurate diagnostic tool to detect multiple intestinal pathogens in a single sample with rapid turnaround and high sensitivity/specificity. BioFire's FilmArray Gastrointestinal Panel is an FDA approved syndromic multiplex PCR assay which evaluates stool for 22 common bacterial, viral and parasitic targets. Studies using multiplex assays have found 31.5% of positive stool samples had multiple pathogens. The clinical implication of detecting multiple pathogens is poorly understood. This study will add to the body of knowledge on pathogen co-detection in routine stool PCR use. Methods: The study was designed as a retrospective, descriptive, hypothesis-generating study to evaluate the co-detection of pathogens with BioFire FilmArray Gastrointestinal Panel in an adult community population. Patients with stool PCR positive for ≥1 pathogen within the date range of 01/01/15-06/30/16 were obtained. Inclusion criteria was age ≥18 and having a stool PCR with ≥1 pathogen within a community health network in the study date range. Patients with tests repeated within 14 days of initial sample were excluded from the analysis. Demographic data at the time of sample collection were obtained. Results: Of 710 patients with pathogen detection, 119 (16.8%) had more than one. Bacterial-viral codetections were seen in 50.4% of co-detection samples, while 39.5% of co-detections were bacterialbacterial. Viral-viral, bacterial-parasitic, and bacterial-parasitic-viral co-detections were less frequent at 5%, 3.4%, and 1.7%. Certain organisms (E. coli O157:H7, P. shigelloides, Sapovirus, EAEC, and Cryptosporidium) when positive on stool PCR testing, had a ≥50% occurrence as a co-detection rather than in isolation. The most common patterns of co-detection were Norovirus/C. difficle, EPEC/C. difficle, EPEC/Campylobacter, and EPEC/Norovirus at 19.3%, 7.6%, 5.9%, and 5.9%. Conclusion: Our study highlights a high frequency (16.8%) pathogen co-detection in patients with a positive stool PCR test. It also suggests that bacterial-viral co-detections is the most commonly identified combination. The most frequent pathogen specific combination was Norovirus with C. difficle accounting for 19.3% of co-detections. More information is needed on the significance of co-detections and their treatment. The information obtained in this study is intended to add to the current body of knowledge and to be used for the generation of hypotheses in future studies.