Population Ecology-Quantitative Microbial Risk Assessment (QMRA) Model for Antibiotic-Resistant and Susceptible <i>E. coli</i> in Recreational Water

Understanding and predicting the role of waterborne environments in transmitting antimicrobial-resistant (AMR) infections are critical for public health. A population ecology-quantitative microbial risk assessment (QMRA) model is proposed to evaluate urinary tract infection (UTI) development due to recreational waterborne exposures to <i>Escherichia coli</i> (<i>E. coli</i>) and antibiotic-resistant extended-spectrum β-lactamase-producing (ESBL) <i>E. coli</i>. The horizontal gene transfer (HGT) mechanism of conjugation and other evolutionary factors were modeled separately in the environment and the gut. Persistence/dilution dominated HGT in the environment; however, HGT highly impacted predicted ESBL populations in the body. Predicted disability life year (DALY) risks from exposure to ESBL <i>E. coli</i> at concentrations consistent with US recreational water criteria were less than the 10^-6 pppy benchmark value but greater than the susceptible <i>E. coli</i> DALY risks associated with a UTI health outcome. However, the prevailing susceptible dose-response relationship may underestimate ESBL risk if HGT rates <i>in vivo</i> approach those reported <i>in vitro</i>. A sensitivity analysis demonstrated that DALY values, <i>E. coli</i>/ESBL concentrations, and exposure parameters were influential on predicted risks. The model is a preliminary tool to begin the expansion of the QMRA paradigm to explore the impacts of evolutionary changes in AMR risk assessment.