Mapping the evidence for the risks of human exposure and transmission of AMR in the natural environment

Antimicrobials (such as antibacterial and antifungal medicines) are used to treat and prevent infections in humans and animals. Effective antimicrobial drugs are essential to modern medicine and to food production practices. However, the microorganisms that cause many common infections are developing the ability to survive and grow even in the presence of antimicrobials, particularly antibiotics. This antimicrobial resistance (AMR) leads to treatment failure, with consequent poor health outcomes and even death. There has been a rapid recognition both by national and international organisations that AMR is a critical emerging threat to our health and wellbeing. If current trends continue AMR infections could be the leading cause of death globally by 2050. Until recently, most attention has focused on the role that clinical settings, like hospitals, and agricultural settings, such as farms, play in contributing to the development and spread of AMR. But, as a large proportion of AMR infections are now known to be acquired in the community, and many resistance mechanisms to have evolved in environmental bacteria before spread to human pathogens, environmental sources are increasingly recognised as key.

However, the research that has been conducted about human health risks from environmental sources of AMR risk is disparate, covers a wide range of topic areas, and has not previously been brought together systematically. This study will establish what research has been undertaken to assess the role of the environment in AMR acquisition. It will use a research method called "systematic evidence mapping" to ensure that all the relevant research evidence is identified in a robust and non-biased way. The aim is to identify, categorise and describe the range of research evidence available. As well as written descriptions, a series of graphics and tables will be generated as a quick reference to how much research has addressed particular types of issues. This will allow us to see easily where there has been a lot of research and where there has been little or none. This "evidence gap" identification can show where research still needs to be done. We will work with stakeholders to prioritise which evidence gaps are most pressing to fill. Where there is already a body of research, this can in the future be brought together using full systematic review methodologies to form a better understanding of a topic area for policy and practitioners to make evidence based decisions.

Through the focus on AMR, which is acknowledged as a key challenge nationally and internationally, we will identify where, across a range of policy areas, key actions may be needed in environmental policy to contain and reduce the human health risks from AMR in the environment. We will also help identify where more research is needed in an integrated manner across the processes involved in AMR as detailed in the DPSEEA model shown in Figure 1 of the Case for Support. Our ability to access an optimal stakeholder group through existing NERC funded Knowledge Exchange adds considerable value to this project because it facilitates our ability to include stakeholder input across the evidence mapping project - particularly in refining the final scope and identifying priority evidence gaps and gluts. The outputs of the evidence mapping project will be made available to all stakeholders and the wider community through the website being developed as part of existing knowledge exchange activity.

The desire and need for evidence by key stakeholders is demonstrated by the close working relationship between Gaze, Defra and EA. Both the KE Fellowship and JPIAMR network grant were written in response to demand from Defra/EA partners for information and evidence on AMR from an environmental perspective. The proposed evidence mapping exercise will consider evidence on human exposure, colonisation and infection from all environmental matrices (not just water) and will include a UK focused assessment of environmental AMR prevalence in environmental matrices that can be used in future human exposure risk assessments. The issue of AMR and environment has been prioritised by the United Nations Environment Programme (Gaze co-ordinating the UNEP report on AMR in the environment to be considered at the next UN Environment Assembly), the European Environment Agency (Gaze recently co-organised a meeting on AMR and environment at EEA headquarters in Copenhagen) and at EU level demonstrating the importance and timeliness of this proposal in contributing to understanding of what is undoubtedly a huge global issue.