Wastewater sampling could be a low-cost strategy for assessing patterns of antibacterial resistance across urban populations. We aimed to quantify fluoroquinolone-resistant (FQ-R) Enterobacterales, third-generation cephalosporin-resistant (3GC-R) Enterobacterales, carbapenem-resistant Enterobacterales, and the blaCTX-M-15 and blaKPC genes in influent wastewater from 12 diverse sewersheds across metro Atlanta over 2 seasons; examine associations between culture- and digital PCR-based outcomes; and investigate relationships between sewersheds' sociodemographic characteristics and concentrations of AR bacteria in wastewater. FQ-R Enterobacterales, 3GC-R Escherichia coli, and 3GC-R Klebsiella, Enterobacter, or Citrobacter spp. (KEC) were detected in 79-94% of samples (n=34), with concentrations differing among sewersheds. Carbapenem-resistant E. coli and KEC were not reliably detected. The blaCTX-M-15 gene was detected in every sample, and we detected trends towards an association with 3GC-R E. coli and KEC, suggesting potential utility of this gene as a monitoring target. The blaKPC gene was detected in every sample despite carbapenem-resistant E. coli and KEC not reliably being detected, suggesting it is not an appropriate indicator for these bacteria. After accounting for season, repeated measures, and potential healthcare inputs, we found that sewersheds with higher proportions of crowded households, Hispanic, non-Hispanic Asian, and individuals speaking a language other than English at home had higher flow-normalized concentrations of FQ-R Enterobacterales, 3GC-R E. coli and/or KEC in their wastewater. Comparisons with human data are needed to determine how well sociodemographic patterns observed through wastewater mirror trends in the human population.

The authors have declared no competing interest.

This work was supported by an award from Emory University's Research Council. MLN was supported by Emory University and the MP3 Initiative. The content is solely the responsibility of the authors and does not necessarily represent the official views of Emory University or the MP3 Initiative.

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Raw data needed to replicate our main analyses are available through the Open Science Framework (OSF): https://osf.io/8fcj6/. Sewershed-level sociodemographic characteristics and flow-normalized concentrations of AR bacteria and ARGs are depicted at: https://4f37k2-cameron7564.shinyapps.io/testmap/.

https://4f37k2-cameron7564.shinyapps.io/testmap/

https://osf.io/8fcj6/