Geospatial Patterns of Antimicrobial Resistance Genes in the US EPA National Rivers and Streams Assessment Survey

Antimicrobial
resistance (AR) is a serious global problem due to
the overuse of antimicrobials in human, animal, and agriculture sectors.
There is intense research to control the dissemination of AR, but
little is known regarding the environmental drivers influencing its
spread. Although AR genes (ARGs) are detected in many different environments,
the risk associated with the spread of these genes to microbial pathogens
is unknown. Recreational microbial exposure risks are likely to be
greater in water bodies receiving discharge from human and animal
waste in comparison to less disturbed aquatic environments. Given
this scenario, research practitioners are encouraged to consider an
ecological context to assess the effect of environmental ARGs on public
health. Here, we use a stratified, probabilistic survey of nearly
2000 sites to determine national patterns of the anthropogenic indicator
class I integron Integrase gene (intI1) and several
ARGs in 1.2 million kilometers of United States (US) rivers and streams.
Gene concentrations were greater in eastern than in western regions
and in rivers and streams in poor condition. These first of their
kind findings on the national distribution of intI1 and ARGs provide new information to aid risk assessment and implement
mitigation strategies to protect public health.