Antimicrobial resistance (AMR) is among the top 10 public health threats, with nearly 5 million deaths in 2019 linked to AMR-related bacterial infections. (1) A One Health approach is needed to combat AMR.

Healthcare-based surveillance (HBS) of AMR provides incomplete information about the scope of the AMR threat. HBS screens only patients seeking medical attention, lacking community-level representativeness, and suffers from underreporting. (2) Consequently, researchers are turning to wastewater-based surveillance (WBS) to complement HBS. (3) WBS can provide information about AMR circulating within communities and hospitals, offering a comprehensive understanding of AMR prevalence. However, the surveillance targets and data obtained from WBS are distinct from those derived from HBS, creating uncertainty regarding their utility to the public health sector and ability to yield policy relevant information. In May 2024, participants in a workshop during the 7th Environmental Dimension of Antimicrobial Resistance (EDAR7) conference (Montréal, Canada) sought to answer four questions aimed at advancing the policy relevance of AMR data generated by WBS.@en

Risk assessment is critical for identifying target concentrations of antibiotic resistant pathogens necessary for mitigating potential harmful exposures associated with water reuse. However, there is currently limited available data characterizing the concentrations of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in recycled water to support robust efforts at risk assessment. The objective of this systematic review was to identify and synthesize the existing literature documenting the presence and abundance of ARB and ARGs in recycled water. In addition, this review identifies best practices and explores monitoring targets for studying ARB and ARGs in recycled water to guide future work and identifies key research needs aimed at better supporting quantitative microbial risk assessment focused on recycled water and antibiotic resistance. Future efforts to collect data about ARB and ARG prevalence in recycled water should report concentration data per unit volume. Sample metadata should also be provided, including a description of treatment approach, a description of planned water uses (e.g., potable, irrigation), methods for conveyance to the point of use, and available physicochemical water quality data. Additional research is needed aimed at identifying recommended ARB and ARG monitoring targets and for developing approaches to incorporate metagenomic data into risk assessment.@en

Antibiotic-resistant bacteria and antibiotic resistance genes are abundant in stormwater, yet there is no consensus regarding how to assess their public health risks. We systematically reviewed the literature and identified 15 studies that provided quantitative occurrence and/or abundance information that was linked to stormwater. Sampling and data analysis approaches across studies varied widely, emphasizing that standardized approaches are needed to pool data across studies in a risk analysis. The amounts, timing, and intensity of precipitation within the storm sewershed for fate and transport were rarely considered and/or reported in relation to concentrations of resistance determinants among the reviewed studies. Linking hydrologic and sewershed characteristics to microbial community composition and antibiotic resistance determinants may help improve our understanding of risk and improve sampling protocols. Research needs for ARB and ARG quantification and assessment are discussed, with an emphasis on informing quantitative microbial risk assessments.

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