Research and analysis

Antimicrobial resistance in the environment: risk screening and prioritization tool: summary

Published 24 October 2024

Applies to England

1. Chief Scientist’s Group report summary

This project developed a prioritisation approach to assess a range of different environmental scenarios for human exposure to microorganisms resistant to antimicrobials and hence compare their significance for human health.

1.1 Background

Antimicrobial resistance (AMR) is a major concern for humans, animals, plants, and the wider environment. The Government’s 20-year Vision for AMR and the 5-year National Action Plan outline how the UK will address the AMR challenge. Studies have indicated that people can be infected by resistant bacteria through environmental routes, for example in recreational use of coastal bathing waters, but there is no agreed method to enable comparison of risks between different exposure scenarios. This project aimed to provide a risk assessment framework to enable such comparisons to be made in a structured and repeatable manner.

1.2 Approach

We developed a risk modelling framework, primarily for pathogenic antimicrobial resistant bacteria. However, its principles are broadly applicable to other resistant pathogens, including fungi and viruses. The framework focuses on direct human exposure via ingestion, inhalation, and skin contact, assuming that the resistant pathogens have entered the environment and are present at the point of human exposure. It follows a source, pathway, and receptor approach as used in traditional environmental risk assessment. The framework uses a qualitative risk assessment approach, organized into 4 modules:

• Module 1: Concentration of resistant pathogens in the environment.
• Module 2: Probability of human exposure via the environment.
• Module 3: Risk for the individual’s health in contact with the environment.
• Module 4: Risk to public health beyond the population exposed via the environment.

1.3 Results

Detailed recommendations are given to support standard evaluations of the key factors involved in each module and the rationale for defining the proposed qualitative assessment criteria from quantitative and non-quantitative assumptions. We have followed similar approaches to those adopted in food safety and clinical uses, so the framework is potentially useful to a wide range of people who may become involved in the evaluation of AMR microorganisms in the environment. The modular structure used and the ways in which probabilities or risks are estimated and displayed at appropriate break points allows the risk assessor to use the framework for different purposes. A tool has been developed to illustrate how the framework can be applied in practice with a graphical user interface for easier visualization and ranking of the results.

1.4 Conclusion

A problem with some proposed scenarios of concern for environmental AMR is a lack of transparency in how the scale and scope of such risks are assessed and how they compare with the concerns raised by other potential scenarios. Our work provides the first steps in developing a standardised approach to overcome this issue, with a major strength being its flexibility to test a wide variety of scenarios incorporating new microorganisms and changes to the population and/or the environmental compartments of interest. The report illustrates the level of detail required to perform even qualitative assessments and so prioritize risk for different organisms, populations, and environments.

1.5 Publication details

This summary relates to information from project SC2200031/R, reported in detail in the following output:

• Title: Antimicrobial resistance in the environment – risk screening and prioritisation tool
• Project manager: Dr Alwyn Hart, Chief Scientist’s Group
• Research contractor: Ausvet Europe

Appendices 4 and 5 from this project are available on request via: research@environment-agency.gov.uk.

This project was commissioned by the Environment Agency’s Chief Scientist’s Group, which provides scientific knowledge, tools, and techniques to enable us to protect and manage the environment as effectively as possible.

The project was carried out as part of the Environment Agency Chief Scientist’s Group research into AMR in the environment as part of the PATH-SAFE programme funded by HM Treasury through the Shared Outcomes Fund.

Enquiries: research@environment-agency.gov.uk.

© Environment Agency