Molecular Detection of Gastrointestinal Pathogens Using a Multiplex Gastrointestinal Panel and Their Associations With Demographic and Clinical Characteristics.

Background Acute gastroenteritis causes morbidity across all age groups, and timely, effective identification of its etiologic agents is essential for clinical management and antimicrobial stewardship. Conventional diagnostic methods have limited sensitivity and often fail to detect coinfections or specific bacterial pathotypes. In contrast, molecular methods, such as FilmArray panels, are rapid, highly sensitive, and capable of detecting coinfections. This study aimed to characterize gastrointestinal pathogens detected by the BioFire FilmArray Gastrointestinal Panel (BioFire Diagnostics, LLC, Salt Lake City, UT, USA; a bioMérieux company) and to evaluate their association with demographic and clinical characteristics among patients at Hospital Angeles Lindavista, Mexico City, Mexico. Methods A retrospective observational study conducted from January 2022 to July 2025 included all patients who underwent gastrointestinal molecular testing. Demographic data, clinical characteristics, and multiplex PCR results were extracted from electronic medical records and the FilmArray database. Data were analyzed using descriptive statistics, logistic regression, Fisher's exact test, and Spearman correlation. Results An analysis of 1,120 samples found an overall positivity rate of 906 (81%). Coinfections were present in 543 (49%) cases. The most common pathogens were enteropathogenic Escherichia coli (E. coli, EPEC; 374, 33.4%); enteroaggregative E. coli (EAEC; 281, 25.1%); and enterotoxigenic E. coli (ETEC; 231, 20.6%). Rotavirus A (206, 18.4%) and norovirus GI/GII (168, 15%) were the most frequent. Positivity was highest in children under five (147, 84.48%) and lowest in adults over 60 (129, 73.71%). Seasonal patterns showed unexpected peaks of rotavirus in spring-summer and of Cyclospora cayetanensis in summer. No significant association was found between pathogen presence and comorbidities, likely due to many missing clinical details. A negative correlation among major E. coli pathotypes suggests competitive exclusion. Conclusion The BioFire FilmArray Gastrointestinal Panel identified pathogen patterns that conventional methods miss. Age and seasonal trends highlight the need for localized epidemiological surveillance. These results encourage the use of molecular diagnostics in routine assessments of gastrointestinal infections and support antimicrobial stewardship efforts. Future studies should include clinical severity metrics and evaluate patient outcomes to connect molecular detection with clinical significance.