Spatial and Temporal Prevalence of Foodborne Bacterial Pathogens in Water-Overlying Sediments in the Mid-Atlantic United States

Abstract The presence of Fecal Indicator Bacteria (FIB) in the sediments of Conococheague Creek, PA, has been documented. However, the prevalence of pathogenic bacteria in these sediments and seasonal influence remain largely unexplored. This study aimed to fill this gap by investigating the presence and temporal distribution of foodborne pathogens, including Salmonella spp., Listeria monocytogenes , and Escherichia coli O157:H7 in water-overlying sediments at selected locations in Conococheague Creek. Over a three-year period, sediment samples were analyzed to enumerate total coliforms, fecal coliforms, and generic E. coli . Results indicated a substantial microbial presence, with total coliforms showing the highest average concentrations, particularly during the warmer seasons. Compared to other sampling sites, FIB concentrations were consistently higher at the SS site, a location characterized by low-intensity urban development. Both Salmonella spp. and L. monocytogenes were detected across all tested sites, with L. monocytogenes observed more frequently than Salmonella spp. Additionally, a higher prevalence of Salmonella spp. was observed during the warmer months, suggesting seasonal influences on its detection. Conversely, L. monocytogenes was detected throughout the year, with a significant increase during the colder seasons. The I81 site, an area dominated by agricultural activities like crops and pasture production, showed higher prevalence of Salmonella spp. and L. monocytogenes compared to the other two sites, suggesting a greater contamination risk in irrigation water sources. These findings emphasize the need for continuous, year-round monitoring of sediment microbial dynamics across the watershed to safeguard irrigation water quality and minimize the risk of pathogen transmission to fresh produce.