Background: The similar presentations in relapse of inflammatory bowel disease (IBD) and enteric infection pose substantial barriers to diagnosis and treatment. The objective of this study was to investigate the endoscopic and histologic predictors of enteric infection in patients with IBD and an exacerbation in symptoms using a multiplex PCR-based stool test for 22 pathogens. Methods: We reviewed the records of 691 patients with IBD who underwent a gastrointestinal pathogen panel PCR stool test (GI PCR; BioFire FilmArray) during an exacerbation of symptoms between January 2015 and May 2017. We identified patients who underwent endoscopy within 30 days of the test and collected baseline characteristics, PCR outcomes, medication exposures, and endoscopic and histologic findings. Results: 77 patients underwent endoscopy within 30 days of a GI PCR test (Table 1). 26 (33.8%) were positive for 14 enteric pathogens with E.coli species (14, 42.4%) and Norovirus (5, 15.2%; Table 2) as the most common. Endoscopic esophagitis was more common in patients with a positive test (p=0.04), but there were no other predictors of an infection including ileitis (p=0.43) and colitis (p=0.58) on endoscopy or chronicity (p=0.21), architectural distortion (p=0.65), and granulomas (p=0.46) on histology. These findings did not differ between viruses and bacteria. Of patients who tested positive, 12 (46.2%) received antibiotics. Patients who tested negative were more likely to have IBD medications added or up-titrated (p=0.004). Conclusions: Endoscopic and histologic findings did not differentiate flare of IBD from enteric infection. Our results suggest that these entities may elicit similar endoscopic and histologic findings, or coexist, and PCR stool testing may identify potential pathogens. As PCR testing significantly impacted management, further study is required to evaluate the impact of various enteric infections on the course of IBD and treatment strategies following GI PCR testing.
