The Prevalence and Diversity of Antibiotic Resistant Bacteria in a Mixed-use Watershed 

Antibiotic resistance and antibiotic resistant (AR) pathogens present a major and increasing public health challenge. However, questions remain regarding the role of the environment and water treatment systems as transmission vehicles and environmental reservoirs of AR genes and pathogens. We will investigate the abundance and distribution of genes for antibiotic resistance and AR pathogens in surface waters, as well as their relationship to land use and wastewater infrastructure. This project will build on existing research programs examining microbial community composition and the prevalence of AR pathogens within the Upper Oconee Watershed in Georgia, a mixed-use watershed encompassing natural, agricultural, industrial, and residential areas. We propose three activities: 1.) Determine the prevalence and abundance of AR gene markers in a sample archive encompassing 5 years of quarterly collection of bacterial DNA samples from the Upper Oconee watershed and evaluate their correlation with markers of human impact, 2.) Extend a current project evaluating the prevalence and AR profiles of Salmonella, Escherichia coli, and Enterococcus in the watershed to cover a total of 4 years of sample collection and tracking, implement additional monitoring of Enterobacteriaceae and Staphylococcus aureus in the watershed, and measure antibiotic residues in water samples, and 3.) Develop a new assay to evaluate the presence and diversity of bacteria in a water sample that are resistant to select antibiotics by pairing enrichment culture with high-throughput sequencing based 16S rRNA gene amplicon analysis. Together, these activities will generate a rich dataset that enhances our understanding of the prevalence and abundance AR genes and pathogens in surface waters, and allows us to evaluate the potential role of surface waters as a reservoir of and potential vehicle for the spread of antibiotic resistance in the environment.