Use of a multiplex DNA extraction PCR in the identification of pathogens in travelers' diarrhea

Background: Diarrhea is one of the most common ailments afflicting travelers with attack rates of 30-40% for medium to high-risk destinations. As travelers' diarrhea (TD) is syndromic and caused by a wide range of pathogens, including bacteria, parasites and viruses, multiplex deoxyribonucleic acid (DNA) extraction polymerase chain reaction (PCR) technology can be useful for determining the etiology of TD pathogens. Objective: The goal of this retrospective study was to produce clinically relevant and useful data on gastrointestinal illness related to travel identified by culture-independent methods of diagnosis-use of the multiplex DNA extraction PCR platform (BioFire FilmArray GI Panel) and to describe the use of this technology in detection of enteric pathogens. Method: We reviewed our data in returned travelers from May 2014 to March 2017, looking at demographics, country of travel, number of pathogens found and pathogens by specific region. Results: Stool analysis by DNA extraction PCR was obtained in 388 post-travel patients. Three hundred and twentyseven of these had diarrhea or other enteric symptoms. Sixty-one travelers presented with enteric symptoms and were diagnosed with post infectious irritable bowel syndrome (PI-IBS) after stool analyses were negative. Of those with diarrhea or gastrointestinal (GI) symptoms and excluding those diagnosed with PI-IBS, 207 patients tested positive for at least 1 enteric pathogen (63.4%). Eighty of those patients were found to have multiple pathogens. Viral pathogens were identified in 38 patients, 18% of the total number of cases. Conclusion: The BioFire FilmArray GI Panel was associated with better detection of pathogens than historical controls while also allowing prompt and accurate diagnosis and potential treatment. A higher proportion of viral pathogens compared with historical assumptions was identified as well as mixed infections with multiple pathogens, a phenomenon largely unknown to clinicians before this technology became available.