Antimicrobial resistant E.coli and genes can move freely between people, animals and the environment, a new study in Malawi and Uganda shows.
The new findings could help inform future public health interventions to reduce the spread of drug-resistant infections and help us understand how to tackle the threat of antimicrobial resistance (AMR).
Researchers from Liverpool School of Tropical Medicine (LSTM), Wellcome Sanger Institute, the Malawi Liverpool Wellcome Programme (MLW), and others explored the transmission of resistance across Uganda and Malawi.
The results, published in Lancet Microbe, support taking a One Health approach when trying to stop the spread of AMR, providing genomic evidence that suggests that drug-resistant bacteria can move freely between humans, animals, and the environment in certain regions.
The researchers stress that integrated public health interventions are required to combat AMR, ones that take all transmission routes into account. For example, antimicrobial stewardship in livestock, wildlife, and wastewater, as well as humans.
AMR is a global health threat that causes more than 1.27 million deaths each year, with low-and middle-income countries experiencing a particularly high burden. Understanding AMR is critical to stopping its spread and protecting the effectiveness of lifesaving treatments.
Dr Patrick Musicha, first author on the paper, and based at MLW, LSTM and Wellcome Sanger Institute, said: “Our study provides direct genomic evidence that antimicrobial resistance can move freely between humans, animals, and the environment and henceunderscores the urgent need for truly One Health interventions for combating antimicrobial resistance. If we are ever able to slow the spread of treatment-resistant infections, we must take these different transmission routes into account and develop integrated public health interventions that address multiple ways that the bacteria can spread.”
The research is part of the DRUM consortium (Drivers of antimicrobial Resistance in Uganda and Malawi), led by LSTM. This programme aims to understand how water, sanitation and hygiene practice interact with antimicrobial usage to facilitate the transmission of AMR-bacteria in Uganda and Malawi.
In this study, researchers analysed over 2,300 genomes of E. coli bacteria from five sites in Uganda and Malawi, revealing high genomic diversity across humans, animals and the environment. These were sequenced at the Sanger Institute and the whole genome sequences were used to assess relatedness and resistance-gene exchange between strains.
The team found no strong barriers limiting transmission of the bacteria or the genes encoding AMR between human, animal and environmental sources, and antibiotic-resistant genes that were shared across all sources. This indicates that interventions focused on a single group – for example, antimicrobial stewardship programmes targeting humans only – may be insufficient.
Professor Nick Thomson, senior author at the Wellcome Sanger Institute said: “Strategies to slow the spread of antimicrobial resistance are only effective if we have the full picture, which is why genomic research is crucial to informing public health interventions. It also shows that we need to understand this problem in all settings given how connected we all are globally. This research shows that in under-resourced countries, traditional interventions and research that focus on the human clinical setting may miss the routes bacteria and the antimicrobial resistance genes they carry are spreading, including via animals. We hope that our work shows how important it is to focus on the gene as the ‘unit of transmission’ for AMR and that to be fully informed we need a true, holistic One Health approach to help reduce the burden of treatment-resistant infections.”