Characterization of Escherichia coli Isolates in Recreational Waters: Implications for Public Health and One Health Approach

Escherichia coli is commonly found in the gastrointestinal tract of warm-blooded animals and is routinely used as an indicator of fecal contamination in recreational waters. While most E. coli are commensal, some can harbor pathogenic potential, posing a major public health risk. This study investigated the sources of fecal contamination in recreational waters through the characterization of E. coli isolates. Presumptive E. coli detection was performed using selective and differential media, confirmed by PCR, and followed by characterization. E. coli were detected in all studied aquatic environments, with most isolates belonging to phylogenetic groups D1 (24%, non-human mammals) and B1 (20%, birds), suggesting animals as primary contaminants sources. Among E. coli isolates, 35% were identified as diarrheagenic E. coli (DEC), with enterotoxigenic (34%) and enterohemorrhagic (26%) being the most prevalent pathotypes. Furthermore, 85% of all isolates and 86.5% of DEC isolates exhibited multi-drug resistance, with highest rates displayed in phylogenetic subgroups A1 (human and non-human mammals) and B1. This study highlights the importance of the One Health approach encompassing a human, animal, and environmental holistic health perspective to effectively manage public health strategies and ensure the safety of beachgoers.