EARLY HEARING DETECTION AND INTERVENTION VIRTUAL CONFERENCE
MARCH 2-5, 2021

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5/24/2018 | 3:15 PM - 3:30 PM | THE PREVALENCE OF ANTIBIOTIC RESISTANCE GENES IN US WATERWAYS AND THEIR RELATIONSHIP TO WATER QUALITY AND LAND USE INDICATORS | 410 A

THE PREVALENCE OF ANTIBIOTIC RESISTANCE GENES IN US WATERWAYS AND THEIR RELATIONSHIP TO WATER QUALITY AND LAND USE INDICATORS

Antibiotic resistance genes (ARGs) in freshwaters are an emerging contaminant of concern. We used 1,747 water samples from the USEPA’s 2013-2014 National Rivers and Streams Assessment and digital-droplet polymerase chain reaction techniques to quantify the concentrations (target molecules/ml) of several ARGs across the conterminous US. Median ARG concentrations ranged from ~7-22 molecules/ml (max=32,231 molecules/ml). Several ARGs were positively and significantly related to watershed urbanization and agriculture. For example, multiple regression showed a positive relationship between sul1 (associated with drug-resistant Salmonella) and watershed urbanization and agriculture (multiple-r²=0.34). Likewise, these watershed metrics explained 37% of the variation in intI1, a gene that facilitates acquisition of drug resistance in bacteria. ARG concentrations were also positively correlated with turbidity, total suspended solids, and chloride, ammonia, potassium, and nutrient concentrations, but these relationships were weaker (r²=0.04-0.2) than relationships with land use. Hotspot analysis confirmed that ARG concentrations are lower in western mountains and higher in portions of the Midwestern and Northeastern US with distinct spatial clustering, especially in areas with intensive agriculture. This study provides a baseline for ARG concentrations in the Nation’s streams that could be critical for future monitoring of these emerging contaminants.

Disease Ecology
Pollution
Genetics

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Presenters/Authors

Ryan Hill (), US EPA, Pacific Ecological Systems Division, Corvallis, OR, hill.ryan@epa.gov;