FilmArray GI-panel performance for the rapid and multiple detection of gastrointestinal microorganisms in foodborne illness outbreaks in Shenzhen during 2018-2019

Foodborne illness outbreaks can be caused by a great many of gastrointestinal microorganisms including bacteria, viruses and parasites. Acute gastroenteritis is most commonly found in such patients infected with at least one pathogen through food intake. The stool culture has been conventionally used to guide a single diagnosis and therapy. However, traditional methods for identification of a pathogen are time-consuming and have limited sensitivity, leading to false negatives and co-infection omission. The aim of this study was to characterize the multiple etiology of each foodborne illness outbreak in Shenzhen during 2018-2019 by the FilmArray GI panel, and to reveal the seasonality of each causative organism incurring outbreaks. All patients included had a FilmArray GI panel performance and the seasonal characteristics were recorded. A total of 173 patients suffered from foodborne illnesses in 32 outbreaks in Nanshan District of Shenzhen. In total, 365 microorganisms were detected of which 83.8% (306/365) corresponded to bacteria and 16.2% (59/365) to viruses. Co-infections with more than one microorganism were detected in 81.3% (26/32) of the outbreaks. In 153 (88.4%) of 173 patients at least two pathogens were identified. The most common diarrheal pathogen related to outbreaks was EPEC (56%), followed by ETEC (38%), Norovirus (34%), EAEC (28%), Vibrio (25%), Salmonella (22%), P. shigelloides (22%), C. difficile (16%), STEC (3%) and Sapovirus (3%). Bacterial outbreaks occurred with a seasonal distribution with the exception of C. difficile whereas Norovirus outbreaks predominated during the autumn-winter months. The use of the FilmArray GI panel has given us worthy information regarding the epidemiology of pathogens detected in patients with acute diarrhea. It also highlights the importance of multi-pathogen infections and the frequency of diarrheogenic E. coli in foodborne disease outbreaks. More significantly, the rapid and multiple findings may help quickly taking an appropriate precaution, control and treatment.