Background: Rapid and accurate diagnostic tools are needed for appropriate management of infectious diarrhea. Methods: We evaluated the impact of the introduction of rapid multiplex PCR testing using the FilmArray gastrointestinal (GI) panel (BioFire Diagnostics, LLC, Salt Lake City, UT) at our institution, and compared the results to those of standard stool cultures. Results: The most common pathogens detected by the FilmArray GI panel were Clostridium difficile (55.0%), Campylobacter species (20.9%), Salmonella species (12.4%), and Shigella/EIEC species (12.4%). Rates of reproducibility in stool culture for these pathogens ranged from 56.3 to 77.8%. Co-detection of two or more organisms was common (24.2%), most commonly involving EPEC, EAEC, ETEC, and STEC. The time from arrival in the Emergency Department to discharge or admission to the hospital was unchanged after the introduction of FilmArray GI panel, but length of hospital stay was shorter (3 vs. 7.5 days, p = 0.0002) for the FilmArray group. The time to empiric antibiotics did not differ significantly, but optimal antibiotics were started earlier after introduction of the FilmArray GI panel (hospital day 1 vs. 2, p < 0.0001). More patients were discharged without antibiotics after introduction of the FilmArray GI panel (14.0% vs. 4.5%; p < 0.001). Conclusion: Our results demonstrate that the FilmArray GI panel is an important tool for improving both patient care and antibiotic stewardship, despite the tendency for positive results with multiple pathogens.

Streptobacillus moniliformis, the cause of rat-bite fever (RBF) in the United States, has rarely been reported as a cause of infectious endocarditis. In the majority of previously reported cases, the diagnosis was clinically- based in patients with underlying valvular abnormalities in the setting of positive blood culture for Streptobacillus moniliformis. We report a case of native valve endocarditis secondary to Streptobacillus moniliformis in a woman with a mitral valve vegetation but negative blood cultures where the diagnosis was established using molecular diagnostics on the valvular tissue.

In immunocompromised patients, histoplasmosis may present as disseminated disease. We present a 52-year-old Caucasian male with symptoms of dyspepsia, postprandial epigastric pain, nausea, and nonbloody diarrhea. Upper and lower gastrointestinal endoscopies were suspicious for inflammatory bowel disease (IBD); however, biopsies were consistent with histoplasmosis, specifically in the duodenum.