Researchers discover latent antimicrobial resistance across the world

A team of researchers has discovered that latent antimicrobial resistance is more widespread across the world than known resistance. They call for broader surveillance of resistance in wastewater.

Technical University of Denmark

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A team of researchers has discovered that latent antimicrobial resistance is more widespread across the world than known resistance. They call for broader surveillance of resistance in wastewater, as the problematic genes of the future may be hiding in the widespread reservoir of latent resistance genes. The research has been published in Nature Communications.

A group of researchers has analysed 1,240 wastewater samples from 351 cities in 111 different countries and found that bacterial latent antimicrobial resistance is widespread on all the world’s continents. The research was coordinated by the DTU National Food Institute in Denmark. The antimicrobial resistance genes investigated do not currently pose a major risk, but some of them probably will in the future, according to the researchers, who on the basis of the study recommend enhanced surveillance of antimicrobial resistance in wastewater. The research has been published in the highly regarded scientific journal Nature Communications (insert link: https://doi.org/10.1038/s41467-025-66070-7).

“The research shows that we have a latent reservoir of antimicrobial resistance that is far more widespread around the world than we had expected,” says researcher Hannah-Marie Martiny, who, together with Associate Professor Patrick Munk from DTU National Food Institute, is first author of the study.

The researchers compared the geographical distribution of antimicrobial resistance genes, both latent and already active (in the following referred to as acquired), and found a far wider geographical distribution of latent resistance genes than acquired ones.

“To curb future antimicrobial resistance, we believe that routine surveillance of antimicrobial resistance in wastewater, in addition to including already acquired resistance genes, should also encompass latent resistance genes, in order to account for tomorrow’s problems as well,” says Patrick Munk.

Consistent with previous investigations, the study shows that acquired resistance genes are present in higher amounts in sub-Saharan Africa, South Asia and the Middle East and North Africa (MENA) regions than in other parts of the world.

Hope of being able to curb a pandemic

It is natural for bacteria to have genes that can make them resistant to antibiotics, and such genes are found everywhere, for example in soil, water and humans. However, our use of antibiotics and other environmental pressures (see the section “Environmental pressures determine antimicrobial resistance” below) have driven resistance to spread to such an extent that the World Health Organization (WHO) has termed antimicrobial resistance (AMR) a pandemic (insert link: https://www.who.int/westernpacific/newsroom/commentaries/detail/the-next-pandemic-is-already-here--antimicrobial-resistance-is-upending-a-century-of-achievements-in-global-health).

When researchers around the world examine the scale and spread of the problem, they typically focus on resistance genes that are already able to jump between bacterial hosts. Acquired antibiotic resistance genes constitute a real challenge because they make treatment of humans and animals with antibiotics difficult or impossible.

Expanded surveillance would offer hope that researchers can determine where and how antimicrobial resistance arises and spreads and can map the ecology of the genes.

“By tracking both acquired and latent antimicrobial resistance genes, we can gain a broad overview of how they develop, change hosts and spread in our environment and thereby better target efforts against antimicrobial resistance (AMR). Wastewater is a practical and ethical way to monitor AMR because it aggregates waste from humans, animals and the immediate surroundings,” says Hannah-Marie Martiny

The study also shows that, globally, there are more latent resistance genes spread across the world than acquired resistance genes. Only in sub-Saharan Africa are there equal numbers of each.

“In general, I don’t think we need to be too worried about most latent antimicrobial resistance genes, but I do believe that some of them will eventually cause problems, and we would like to know which ones; because with that knowledge we may be able to predict which bacteria in future can be stopped by which medicines,” says Hannah-Marie Martiny; a view shared by Patrick Munk.

“When new antibiotics are developed – a process that takes many years – bacteria may already have invented new ‘scissors’ capable of destroying them. If we can study both types of genes over time, we may be able to find out which of the latent genes become problematic resistance genes, how they arise and how they spread across geography and bacteria, and in that way lessen the burden of antimicrobial resistance,” says Patrick Munk.

Latent antibiotic resistance mapped using functional metagenomics

There are several ways to test whether genes confer resistance to antibiotics, both through AI-based predictions and laboratory experiments. However, there is a degree of uncertainty associated with computer predictions, which can also blur the interpretation of results.

Latent resistance genes are identified by extracting DNA from a sample and then testing random DNA fragments to see whether they can confer antimicrobial resistance. The method is called functional metagenomics and involves inserting DNA fragments into a harmless bacterium. The bacteria that survive must have received a piece of DNA that provides resistance. This does not necessarily mean that the DNA fragment can move between bacteria naturally in the environment.

The difference between latent resistance genes and acquired resistance genes is precisely that acquired resistance genes are known to be able to jump to new bacterial hosts, whereas latent resistance genes can jump to new bacterial hosts in the laboratory, but researchers do not yet know whether they will at some point be able to do so in the environment.

“Our concern is that some latent resistance genes will become acquired resistance genes and thus become able to jump to different bacterial hosts out in the environment. Especially because the research also shows that they are present in large numbers in so many places around the world. That is why we would like to see them included in surveillance,” says Patrick Munk.

To what extent latent resistance genes develop into problematic acquired resistance genes is something the researchers do not yet know. Broad surveillance of both latent and acquired resistance genes will help answer this question.

May prevent treatment of infectious diseases

The classic way in which society becomes aware of acquired resistance genes is through infectious diseases that cannot be treated with antibiotics because of resistance. At the DTU National Food Institute there is a large collection of resistance genes (insert link: https://genepi.food.dtu.dk/resfinder), which is used by doctors and researchers worldwide when they need to determine whether a bacterium is antimicrobial resistant. In the present study, the occurrence of all the different resistance genes in the wastewater samples was quantified to determine their geographical and environmental distribution.

Environmental pressures determine antimicrobial resistance

The environment acts as the referee in a constant elimination race when it comes to resistant bacteria. When antibiotics are present, susceptible bacteria die first. The few bacteria that initially carry a resistance gene survive and multiply. The following factors in the environment affect, for example, which bacteria die and which survive:

• Residues of antibiotics in the environment (from hospitals, agriculture, wastewater) inhibit or kill susceptible bacteria and give resistant bacteria an advantage, enabling them to spread more easily.
• Disinfectants and biocides, under repeated or prolonged exposure, can select for bacteria that tolerate these agents. These bacteria often also carry genes that confer antimicrobial resistance.

Facts about the study

The study “Geographics and bacterial networks differently shape the acquired and latent global sewage resistomes” has been published in the scientific journal Nature Communications 

The study is based on 1,240 wastewater samples collected from 351 cities across 111 countries, covering all seven continents. The samples were collected from 2016 to 2021.

The research is funded by the Novo Nordisk Foundation (grant NNF16OC0021856, Global Surveillance of Antimicrobial Resistance) and the European Union’s Horizon 2020 research and innovation programme (grant no. 874735).

The study builds on a series of earlier studies:

Time-series sewage metagenomics distinguishes seasonal, human-derived and environmental microbial communities potentially allowing source-attributed surveillance

Genomic analysis of sewage from 101 countries reveals global landscape of antimicrobial resistance 

Global monitoring of antimicrobial resistance based on metagenomics analyses of urban sewage 

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Journal

Nature Communications

DOI

10.1038/s41467-025-66070-7 

Article Title

Geographics and bacterial networks differently shape the acquired and latent global sewage resistomes

Singing mice speak volumes

Cold Spring Harbor Laboratory

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image: 

Cold Spring Harbor Laboratory Assistant Professor Arkarup Banerjee and colleagues find that songs and ordinary vocalizations both arise from the midbrain caudolateral periaqueductal gray (clPAG), seen here.

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Credit: Banerjee lab/CSHL

All mice squeak, but only some sing. Scotinomys teguina, aka Alston’s singing mice, hail from the cloud forests of Costa Rica. More than 2,000 miles north, Cold Spring Harbor Laboratory (CSHL) neuroscientists study these musically gifted mammals to better understand the evolutionary origins of vocal communication. Their research could also tell us something about strokes, autism, and other disorders affecting speech. 

While most of us are familiar with mouse squeaks, “they have a whole other communications system called ultrasonic vocalizations (USVs),” says CSHL Assistant Professor Arkarup Banerjee. USVs are so high-pitched and soft we can only hear them with special devices. That’s not the case for the “songs” of Alston’s singing mice. Most of us can hear them clearly.  

Notably, singing mice can also communicate via USVs. It’s thought that they sing to project across great distances—an important skill for living among the clouds. But just how are these communications physically produced? How do singing mice’s brains, which are comparable to those of ordinary lab mice, enable such complex behavior? Banerjee’s latest study, published in Current Biology, addresses both questions. 

First, Banerjee and his team developed a behavioral test called PARId to characterize the different sounds that singing mice can make. The tests confirmed Alston’s mice use long, loud, rhythmic songs to communicate from afar and USVs for close talking. Banerjee lab postdoc Cliff Harpole then gave the mice helium to see if they produced songs by vibrating their vocal cords or blowing air. The “party trick” offered surprising results, Banerjee says. “For both USVs and songs, the pitch went up. So, we know for sure that they’re produced by a whistle mechanism.” 

Next, CSHL grad student Xiaoyue Mike Zheng used special viruses to target certain areas of the mice’s brains. These tests revealed something arguably even more surprising. It turns out Alston’s mice use the same brain region for singing and USVs. And it’s the same region ordinary lab mice use for daily communications. The finding offers an important clue in the mystery of how mammals’ brains have evolved to enable complex behaviors like social interactions. “This is one of the foundational studies from the lab trying to get into this new domain of how behaviors evolve,” Banerjee explains. “We have found what is common. So now the hunt is on for what’s different.”

In time, the Banerjee lab’s research on vocal communication could have implications for people with profound autism or stroke-induced aphasia. Their findings may even help engineers make AI better at recognizing specific words and noises. Now, how does that sound? 

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Journal

Current Biology

DOI

10.1016/j.cub.2025.10.036 

Article Title

Vocal repertoire expansion in singing mice by co-opting a conserved midbrain circuit node

 

Home hospital care demonstrates success in rural communities

Among acutely ill patients who traditionally would be cared for in a brick-and-mortar hospital, patients transferred quickly and treated at home had 27% lower cost, increased physical activity, and high satisfaction

Mass General Brigham

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One in five people in the United States live in a rural area. Patients in rural communities often struggle to access care because of travel difficulties, high costs and limited resources, leading to worse medical outcomes. With over 150 rural hospital closures since 2010, innovative approaches to care delivery in rural areas are needed. In a new study by investigators from Mass General Brigham and Ariadne Labs, in collaboration with colleagues at rural U.S. and Canadian health centers, researchers found that hospital-level care at home is feasible for patients living in rural areas with acute conditions who traditionally would have been cared for in a brick-and-mortar hospital, and substantially improved experiences of care and physical activity levels. Findings are published in JAMA Network Open.

“Rural health care is in a crisis, and we need to think differently. Hospital-level care delivered in patients’ homes has improved healthcare delivery in urban settings but may fill an even greater need in rural areas, where longer transit times, poor accessibility, and hospital closures challenge access to high quality care,” said David Levine, MD, MPH, MA, Clinical Director of Research & Development at Mass General Brigham Healthcare at Home and Director of Ariadne Labs’ Home Hospital Program. “We’ve shown that home hospital care not only works in rural settings, but that patients also prefer their care at home.”

This randomized controlled trial included 161 adults who required inpatient care for acute conditions (primarily infections, heart failure, chronic obstructive pulmonary disease, or asthma). Participants were recruited after presenting for emergency care at Blessing Hospital (IL), Hazard Appalachian Regional Healthcare Regional Medical Center (KY), and Wetaskiwin Hospital and Care Centre (Canada). They were assigned to either traditional “brick-and-mortar” hospital care for the length of their treatment, or home hospital care, which was administered via twice daily in-home visits with nurses and paramedics and a daily remote visit with a physician or advanced practice provider.

Innovative technologies minimized the need for medical equipment to be brought into patients’ homes. A wireless sticker on the patient's chest took the place of a typical hospital telemetry system for continuous monitoring. Intravenous infusions could be delivered from an ambulatory infusion pump small enough to fit in a fanny pack. A handheld meter could check a patient’s labs right in the home.

Overall, there was no significant difference in cost for the two groups. Notably, when the researchers compared the control group to the home hospital patients who had been transferred home after less than 3 days of brick-and-mortar care, they found that the cost was 27% lower, emphasizing the importance of early transfers. Readmission rates were similar 30 days after treatment, and no major safety differences emerged between groups. Home patients were less sedentary, taking an average of 700 more steps per day than controls. They also reported substantially greater satisfaction—almost double that of their counterparts who received care at the hospital (a net promoter score of 88.4 vs. 45.5, with 100 indicating maximum satisfaction).

The researchers are continuing to analyze how home hospital impacts movement, qualitative experiences, and caregiver experiences. They are also working to develop a mobile clinic, housed in an electric vehicle, with the necessary technology to deliver hospital-level care to any rural area in the U.S.

“Hopefully this work can spur patients, clinicians, and healthcare leaders in rural areas to recommend, request, and build home hospital programs,” Levine said. “Those particular areas that may have lost their hospital may be able to establish home hospital programs that are less expensive than brick-and-mortar care and employ clinicians that work locally. We hope others can use this research to take action in their communities because we have seen that when patients desire certain models of care, those models come to fruition. We feel this may be one innovation to help solve the rural healthcare crisis.”

Authorship: In addition to Levine, Mass General Brigham and Ariadne authors include Patricia C. Dykes, Stuart R. Lipsitz, Meghna P. Desai, Sarah M. Findeisen, Stephanie C. Blitzer, and Ryan C. L. Brewster. Additional authors include, Michelle N. Grinman, Steven C. Amrhein, Mitchell Wicker, Scott M. Harrison, and Mary Frances Barthel.

Disclosures: Levine reported receiving royalties from Biofourmis and is an advisor to Feminai outside the submitted work. Grinman reported receiving in-kind research support to the institution from the Brigham and Women's Hospital Ariadne Labs during the conduct of the study. No other disclosures were reported.

Funding: This study was funded with the support of The Thompson Family Foundation.

 

Paper cited: Levine DM et al. “Hospital-Level Care at Home for Adults Living in Rural Settings” JAMA Network Open DOI: 10.1001/jamanetworkopen.2025.45712

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About Mass General Brigham

Mass General Brigham is an integrated academic health care system, uniting great minds to solve the hardest problems in medicine for our communities and the world. Mass General Brigham connects a full continuum of care across a system of academic medical centers, community and specialty hospitals, a health insurance plan, physician networks, community health centers, home care, and long-term care services. Mass General Brigham is a nonprofit organization committed to patient care, research, teaching, and service to the community. In addition, Mass General Brigham is one of the nation’s leading biomedical research organizations with several Harvard Medical School teaching hospitals. For more information, please visit massgeneralbrigham.org.

About Ariadne Labs

Ariadne Labs, a joint center for health systems innovation at Brigham and Women’s Hospital and the Harvard T.H. Chan School of Public Health, is dedicated to saving lives and reducing suffering by addressing critical gaps in health care systems. Through implementation science and human-centered design, we develop scalable solutions in four key areas: maternal and child health, patient safety, integrated care models, and health care at home. Our work enhances outcomes, alleviates suffering, and promotes dignity in care delivery. Accessed in over 185 countries and impacting more than half a billion lives, we strive to ensure health systems deliver high-quality, equitable care for everyone, everywhere. Learn more at ariadnelabs.org.

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Journal

JAMA Network Open

DOI

10.1001/jamanetworkopen.2025.45712 

Article Title

Levine DM et al. “Hospital-Level Care at Home for Adults Living in Rural Settings” JAMA Network Open DOI: 10.1001/jamanetworkopen.2025.45712

Article Publication Date

1-Dec-2025

US Health care access outcomes for immigrant children and state insurance policy

JAMA Network Open

About The Study: 

In this cross-sectional study of U.S. children, immigrant compared with U.S.-born children had disparities in health care access, which were attenuated in states with the most inclusive state insurance policies, suggesting that inclusive state insurance eligibility policies for immigrant children may improve health care access outcomes for this population. 

Corresponding Author: To contact the corresponding author, Katherine E. Douglas, MD, email katherine.douglas@childrens.harvard.edu.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2025.45826)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

Embed this link to provide your readers free access to the full-text article  

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Journal

JAMA Network Open