One Health action needed as environmental reservoirs fuel drug-resistant infections

Environmental antimicrobial resistance is turning rivers, soils, and even the air into hidden highways for "superbugs," according to a new review that calls for urgent, coordinated action across human, animal, and environmental health. The authors argue that protecting people from drug resistant infections now depends as much on wastewater plants and farms as it does on hospitals.

A growing environmental "superbug" crisis

Antimicrobial resistance (AMR) occurs when bacteria and other microbes evolve the ability to survive medicines that once killed them, making common infections harder or impossible to treat. The World Health Organization already lists AMR as one of the most serious global health threats of this century, with some estimates warning of tens of millions of deaths and massive economic losses if action fails.​

The new study shows that the environment is not just a passive backdrop. Rivers, lakes, soils, oceans, and even air can carry resistance genes and resistant bacteria that move between wildlife, livestock, and people, helping create a truly global network of AMR.​

Key sources and hidden reservoirs

The review highlights several major environmental "hotspots" where resistance builds up and spreads.​

• Hospital and city wastewater treatment plants act as central mixing hubs, collecting antibiotic residues, resistant pathogens, and mobile genetic elements from homes and clinics. Conventional treatment often fails to fully remove these contaminants, allowing resistance genes to persist in effluent water and sewage sludge.​

• Livestock farms and aquaculture systems use large quantities of antibiotics, enriching resistance genes in animal gut microbes and manure that then reach soils, crops, and surrounding waters.​

• Pharmaceutical manufacturing facilities can discharge extremely high levels of both antibiotics and resistance genes, raising the risk that dangerous resistance traits spread downstream.​

Across these sites, resistance genes can hitchhike on mobile genetic elements such as plasmids, making it easier for bacteria to "swap" resistance traits and create multidrug resistant strains.​

Why traditional monitoring is not enough

Most AMR surveillance still focuses on clinical samples, but the authors argue that environmental monitoring needs to catch up. Classic culture based tests remain important because they measure whether bacteria actually survive antibiotics, and they provide live isolates for further study. However, many environmental bacteria cannot be grown easily in the lab, and these methods can miss most of the resistance present.​

Newer tools are rapidly changing the picture:

• Phenotypic methods such as flow cytometry and Raman spectroscopy can track resistant cells and gene transfer in complex samples within hours, without requiring cultivation.​

• Genotypic methods such as high throughput quantitative PCR, CRISPR based assays, and metagenomic sequencing can detect hundreds of resistance genes at once, and identify which bacteria carry them.​

• Long read sequencing now allows researchers to reconstruct entire mobile genetic elements and see exactly how resistance genes are organized and move between hosts.​

"The message is clear" said lead author Huilin Zhang. "No single method can capture the full story of environmental resistance. What we need is integrated surveillance that links what bacteria can do to what genes they carry, and where they are spreading."​

One Health and smarter mitigation

The review is framed within the One Health concept, which emphasizes that human, animal, and environmental health are tightly connected. The authors propose tackling AMR on two fronts source control to reduce the amount of antibiotics, resistant bacteria, and resistance genes entering the environment, and process control to intercept them along key pathways such as wastewater treatment.​

Source control measures include stricter antibiotic stewardship in medicine and agriculture, better regulation in low and middle income regions, and cleaner production in pharmaceutical industries. The authors also highlight emerging "green" solutions, such as enhanced biodegradation of antibiotics, design of more biodegradable drugs, and alternative antimicrobials like peptides and phages.​

On the process side, improved wastewater treatment and waste management are crucial. Conventional disinfection can reduce many resistant bacteria but may leave resistance genes intact, especially in solid waste streams. More advanced approaches such as hyperthermophilic composting, advanced oxidation, membrane processes, nanomaterials, bacteriophage based treatments, engineered DNA scavenging bacteria, and CRISPR based tools show promise but require further research, safety evaluation, and cost reduction.​

Focusing on the riskiest resistance

Instead of simply counting how many resistance genes exist, the authors argue that surveillance and policy should prioritize traits that really drive health risk. Three stand out:​

• Mobility: how easily genes move between bacteria and environments.​

• Host pathogenicity: whether the bacterial hosts are capable of causing disease in humans or animals.​

• Multi resistance: whether genes and their hosts resist multiple key antibiotics, limiting treatment options.​

"Environmental AMR is not just about how many resistance genes we can find" said corresponding author Feng Ju. "What matters most is which genes are mobile, which pathogens carry them, and how they evolve in real world ecosystems. That is where surveillance must focus, and where mitigation will have the biggest impact."​

The authors call for global, standardized protocols that make environmental AMR data comparable across countries and over time. Without such standards, they warn, the world will struggle to spot emerging threats early enough and to design effective One Health interventions that protect both people and the planet.​