July 21, 2026
Overview:
Antimicrobial resistance (AMR) is making infections harder to treat around the world. To track how drug-resistant bacteria spread, surveillance has traditionally focused on hospitals and patients. Increasingly, however, researchers are looking at wastewater as a valuable source of information for surveillance.
Because municipal wastewater contains sewage from entire communities, it can provide a snapshot of the bacteria and antibiotic resistance circulating among people. This makes it a useful tool for monitoring AMR and identifying trends that may not be visible through hospital surveillance alone.
Recognizing this potential, the European Union’s revised Urban Wastewater Treatment Directive, which came into force in 2025, requires large municipal wastewater treatment plants to monitor AMR. However, several important questions remain unanswered: What should be measured? Which methods should be used? How often should samples be collected? And how can the data be used to improve public health?
In this article, OHT’s Dr. Ramanan Laxminarayan and colleagues propose a practical framework to help ensure wastewater surveillance generates information that can guide public health action, support environmental policies, and strengthen efforts to combat AMR.
The Question:
How should wastewater-based AMR surveillance be designed so that it produces information that is useful for protecting public health, improving environmental decision-making, and supporting responsible antibiotic use?
The Findings:
The authors explain that collecting wastewater samples is only the first step. Before deciding what to measure, researchers and policymakers should first ask what they want the surveillance system to achieve. The researchers propose an objective-driven approach to help ensure that surveillance produces information that supports meaningful decisions.
- Define the surveillance objective, such as reducing the emergence and spread of AMR, limiting environmental transmission, or supporting responsible antibiotic use.
- Identify the decisions the data should support, such as improving wastewater treatment, reducing human exposure to resistant bacteria, and updating antibiotic treatment guidelines.
- Determine the knowledge gaps that prevent those decisions from being made effectively, such as understanding where resistance develops, how people are exposed, or how resistance patterns in wastewater compare with those seen in patients.
- Select the most appropriate surveillance methods to answer those questions. These may include measuring antibiotic residues, monitoring antibiotic-resistant bacteria, detecting antibiotic resistance genes, or using newer technologies such as metagenomic sequencing.
The authors emphasize that there is no single test that can answer every question. Different public health goals require different types of measurements and surveillance methods.
Although the framework was developed to support Europe’s wastewater monitoring requirements, the authors note that it could benefit countries around the world. In many low- and middle-income countries, where hospital-based AMR surveillance is limited and sanitation infrastructure is still developing, wastewater surveillance could provide valuable insights into the distribution and trends of AMR in communities and the environment.
By starting with clear public health objectives rather than simply collecting data, countries can build surveillance systems that make better use of resources and generate evidence to inform stronger One Health strategies for tackling antimicrobial resistance.
Read the article in Nature Microbiology here.
