Background : Surveillance of antimicrobial resistance (AMR) in healthcare settings is essential for effective management of infections, optimization of antibiotic treatments and early detection of hospital outbreaks. Traditional surveillance for patients, based on routine clinical antimicrobial susceptibility data and multidrug-resistant organisms (MDRO) screening, has limitations. Wastewater-based surveillance (WBS) has emerged as an alternative tool for benchmarking health markers, as used in wastewater monitoring of virus around the COVID-19 pandemic. WBS can potentially serve as a cost-effective and efficient tool for monitoring resistant pathogens and genes in hospital settings.

Objectives : Here we review the role of WBS for monitoring AMR in hospitals, summarizing current evidence and challenges. Practical recommendations are also provided on what must be considered when implementing AMR WBS programs in hospitals, including system setup, selection of surveillance targets, wastewater collection methods, microbiological processing, and interpretation of WBS-generated data.

Results and implications : WBS could serve as a promising tool for monitoring AMR in hospitals, with the potential to enhance infection control efforts. However, the optimal and validated approach for this purpose has yet to be established. There is significant variability in the methods used for sampling and processing of wastewater, and ideal sampling techniques and microbiological methods for tracking AMR need to be determined. Key knowledge gaps remain regarding the qualitative and quantitative link between AMR detected in hospital wastewater, and hospitalized patients. This link can be influenced by various factors, including presence of antibiotic residues, or biofilm formation in sanitary or effluent pipes and external environmental factors such as rainwater mixing. New research is needed to refine WBS methods for AMR, to better understand the link between wastewater findings and prevalence of AMR in hospitalized patients and to validate WBS effectiveness as a health surveillance strategy, or instrument for benchmarking of AMR prevalence in hospital populations.