Demonstrating a Comprehensive Wastewater-Based Surveillance Approach That Differentiates Globally Sourced Resistomes

Wastewater-based
surveillance (WBS) for disease monitoring is highly
promising but requires consistent methodologies that incorporate predetermined
objectives, targets, and metrics. Herein, we describe a comprehensive
metagenomics-based approach for global surveillance of antibiotic
resistance in sewage that enables assessment of 1) which antibiotic
resistance genes (ARGs) are shared across regions/communities; 2)
which ARGs are discriminatory; and 3) factors associated with overall
trends in ARGs, such as antibiotic concentrations. Across an internationally
sourced transect of sewage samples collected using a centralized,
standardized protocol, ARG relative abundances (16S rRNA gene-normalized)
were highest in Hong Kong and India and lowest in Sweden and Switzerland,
reflecting national policy, measured antibiotic concentrations, and
metal resistance genes. Asian versus European/US resistomes were distinct,
with macrolide-lincosamide-streptogramin, phenicol, quinolone, and
tetracycline versus multidrug resistance ARGs being discriminatory,
respectively. Regional trends in measured antibiotic concentrations
differed from trends expected from public sales data. This could reflect
unaccounted uses, captured only by the WBS approach. If properly benchmarked,
antibiotic WBS might complement public sales and consumption statistics
in the future. The WBS approach defined herein demonstrates multisite
comparability and sensitivity to local/regional factors.