Making waves: From mandates to mechanisms: A transatlantic framework for wastewater antimicrobial resistance management.

Antimicrobial resistance (AMR) in wastewater presents a policy and implementation test: can regulators translate heterogeneous monitoring into affordable actions across treatment, water reuse, and biosolids management? A key transatlantic tension is visible. The European Union (EU) is institutionalizing action through binding wastewater mandates and upstream financing under the recast Urban Wastewater Treatment Directive (UWWTD), while the United States (U.S.) is advancing monitoring design, analytical quality control, and risk-assessment tools without binding federal AMR endpoints. The United Kingdom (UK) and Canada provide contrasts without displacing the EU-U.S. comparison. Organized around EU progress, U.S. constraints, shared bottlenecks, and mutual learning, this perspective identifies a surveillance-to-action gap involving comparability, interpretability, and actionability. Heterogeneous methods, bioinformatics workflows, metadata, and interpretive approaches limit the development of comparable evidence, while uncertain exposure relevance and uneven institutional capacity constrain proportionate responses. The manuscript therefore proposes a transatlantic package comprising: (i) a shared indicator set and quality assurance/quality control (QA/QC) guidance; (ii) shared genomic reference laboratories and materials to reduce cross-study uncertainty; (iii) targeted source-control and treatment priorities aligned with co-benefits; (iv) implementation pathways accounting for affordability and cost-allocation constraints; and (v) adaptive risk assessment supporting evidence-informed decisions under uncertainty for water reuse and biosolids management without requiring universal thresholds for every resistance marker. Recognizing that methods, baselines, thresholds, financing, and management responses are not directly transferable across jurisdictions, a tiered framework is proposed, allowing staged surveillance, minimum QA/QC, standardized metadata, and reference-laboratory support to be adapted and evaluated in other settings. This approach links comparable surveillance to proportionate responses during early EU implementation, supports phased implementation within existing U.S. frameworks, and provides adaptable principles for evaluation elsewhere.