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Medical School team produce evidence maps to explore AMR exposure

Researchers at the University of Exeter’s Medical School have produced two evidence maps to explore the risks of human exposure to AMR. 

Researchers at the University of Exeter’s Medical School have produced two evidence maps to explore the risks of human exposure to AMR in the environment and whether transmission can occur after exposure events, resulting in human health outcomes. An evidence map uses robust, systematic methods to identify, catalogue and describe all the research undertaken on a particular topic.

To do this, they used systematic mapping methodologies and asked two key questions:

1) What is the global research evidence about antibiotic resistant bacteria exposure and transmission to humans from the environment?

2) What research evidence is there measuring prevalence of antibiotic resistant bacteria in the environment in the UK?

For the first map, 40 studies were found globally, which assessed whether people had been exposed to, infected by or colonised from AMR bacteria from environmental sources including water, soil, food (from wild animals or raw plants), and air. Most research has looked at exposure through ingestion/consumption of water or food (wild meat or plants consumed raw).

The second map found 62 studies that investigated the abundance of AMR bacteria in the UK environment. Most research conducted has assessed whether bacteria in water sources are resistant to antibiotics, particularly water flowing into, or out of, wastewater treatment plants.

The maps illustrate that AMR is present in a range of environments and that AMR can transmit from the environment to humans resulting in potential health consequences. However, more research needs to be undertaken to understand underresearched environmental niches.

At the UN Environment Assembly in 2017, the environmental dimension of antimicrobial resistance (AMR) was highlighted as one of the most serious environmental pollution issues of our time. With high levels of AMR in the environment and constant human interaction with it, there is the potential for humans to be exposed to environmental AMR through essential (breathing, eating etc.), occupational (fisherman etc.) and recreational (swimming etc.) activities. A study published in 2022 estimated that there are already 4.95 million deaths per year associated with AMR and 1.27 associated with bacterial AMR. In addition, estimates have suggested that by 2050, AMR will contribute to 10 million deaths annually.

Whilst there is currently no statutory obligation for environmental surveillance of AMR in UK environments, funding has starting to be allocated to explore this problem. The UK government has recently allocated approximately £20 million to study environmental AMR, alongside AMR in food sources, as part of the PATH-SAFE project. In addition, the Environment Agency has secured £2 million for the development of an environmental AMR surveillance programme in the UK.

Articles identified through this mapping exercise can be used to support surveillance and policy in the environment to protect human health and can signpost to knowledge gaps where future research efforts should be focused.

The paper is entitled “Existing evidence on antibiotic resistance exposure and transmission to humans from the environment: a systematic map”, and was funded by a NERC Environmental Evidence for the Future Grant (NE/S015965/1).

Date: 20 April 2022