This concludes a knowledge summary regarding antimicrobial resistance in the environment, made by VKM on behalf of the Norwegian Environment Agency.

Challenges

The summary is based on seven VKM risk assessments on antimicrobial resistance, published in the period 2015 - 2020.

-Most studies on antimicrobial resistance in the environment are descriptive and fragmented. One of the challenges we face is the lack of quantitative data. Quantitative data are needed to understand the dynamics of the environment, over time. When such data are lacking, it is not possible to get a full understanding of exposure and resistance levels and how this varies, states Kaare Magne Nielsen, Scientific Leader of the project group.

Antimicrobial resistance in the environment has three dimensions: antimicrobial resistant bacteria, antimicrobial resistance genes and antimicrobial agents, which include antimicrobial drugs, heavy metals and other compounds that can affect the growth and spread of microbes.

Another challenge the VKM report highlights is that studies evaluated from 2015 to 2020 do not capture the complexity of antimicrobial resistance in the environment.

-The environment is not exposed to individual genes, bacterial species or selective agents such as antimicrobials, heavy metals and disinfectants, but complex mixtures thereof. It is not reflected in the studies, according to Nielsen.

VKM believes it is relevant to compare the summary of knowledge with the report Antibiotic resistance - knowledge gaps and current measures, developed by an interdisciplinary expert group at the Norwegian Institute of Public Health in 2014.

-Some progress has been made in understanding antimicrobial resistance in the environment since 2014, but the proposals and conclusions in the National Institute of Public Health's report (2014) are still valid," says Nielsen.

International efforts

VKM points out the need for greater coordinated international efforts in order to gain a greater understanding of how antimicrobial resistance affects the environment. Such efforts involve the design of studies that go beyond descriptive approaches, the establishment of standardized sampling and analysis regimes, securing data available about use and interaction between selective agents, and the development of monitoring strategies that provide knowledge of longitudinal resistance dynamics.

The knowledge summary has been approved by the Panel on Microbial Ecology.