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A multinational study has found that reducing carbon emissions in addition to limiting antibiotic use could double the effects of containing antimicrobial resistance (AMR) by 2050.
InSight+ spoke to researchers who further suggested that the health care sector, and in particular clinical practice, needs to adopt a wider approach to health to support global AMR goals.
The study, published in Nature Medicine Journal, conducted by a global collaboration of organisations including La Trobe University, has found that not only is climate change responsible for higher rates of antimicrobial resistance, but that the health care industry can play a large role in reducing AMR.
Professor George Liu is a Professor in public health at La Trobe University.
“We need a strategic shift in terms of how to address the challenges of AMR,” said Prof. Liu.
The researchers established statistical modelling to determine the effects of various factors, including climate change, on antimicrobial resistance, using 4502 AMR monitoring records, spanning 32 million isolates from 101 countries, between 1999 and 2022.
“Using these data, the study tested the trajectory of AMR development, combining varying levels of socio-economic development, antimicrobial consumption, and climate factors, creating models that projected the effect on AMR to the year 2050 under four different scenarios,” he said.
“The results indicate that a 50% reduction in antimicrobial consumption could lower AMR by an average of 2.0% by 2050. The reduction, however, is smaller than the potential benefits of sustainable development efforts, which could reduce AMR by 5.4%,” said Prof. Liu.
The research recommends adopting the sustainable development path articulated by the United Nations One Health to achieve AMR containment.
A complex system of variables
The study used data collected by the United Nations, and was also informed by data from individual nations in previous studies.
“In a previous study, we found that the effects of climate change on AMR in colder regions appear more profound than those in warmer regions in mainland China. Different strains of AMR may respond to climate change in different ways. We are currently exploring the potential non-linear correlations between ambient temperature and different strains of AMR,” said Prof. Liu.
“We built momentum until we are able to use global data to predict scenarios of AMR development until the year 2050,” he said.
The researchers relied on myriad variables, including hygiene, income and socio-economic status, weather, vaccination, antibiotic stewardship and access, and many others, to predict AMR development efforts based on global climate action scenarios.
“We can’t use a one-size-fits-all solution. We are highly aware of the differences between countries, in particular between low- and middle-income countries and high-income countries,” he said.
“That’s particularly important in terms of hygiene. For example, safe water and environmental pollution are all factors highly associated with antibiotic resistance,” he said.
“And, of course, those countries also have different health care systems. The antibiotic governance, or stewardship, also differs across countries,” he said.
“Overuse of antibiotics is a serious concern in China, for example: it’s so cheap and accessible. And many consumers store antibiotics, and reuse them,” he said.
“We are also talking about agriculture and animals. Human consumption may only comprise less than half of the consumption of antibiotics,” said Prof. Liu.
“We also collect data about rainfall, and air pollution,” he said.
“So, we need to understand the connections between AMR and all kinds of different potential predictors.”
Climate and AMR
The researchers are currently working to better understand the established links between climate and AMR.
“Overall, the conclusion we got was that climate change may exacerbate the development and spread of AMR,” said Prof. Liu.
“But our current understanding about the effects of climate change on AMR is limited. Such effects are compounded by many factors such as air pollution, antibiotic consumption, and how we prevent infections through adjusting our behaviours,” he said.
“We understand in a warmer environment, bacteria grow faster. And of course, they also need to be exposed to antibiotic products to develop mutation or resistance genes or other mechanisms,” said Prof. Liu.
“From the environmental perspective, it’s not just the temperatures. Rainfall and pollutants can also carry bacteria and spread them to wider regions,” he said.
“From the molecular perspective, we don’t have a good understanding. But we do notice that different resistant bacteria have different responses to climate change. How to develop resistance and how to spread may differ across different strains,” he said.
Prof. Liu said that both viral and bacterial growth are crucial for understanding how climate relates to AMR.
“Through vaccination, people will have a high capacity to fight bacteria. Bacteria don’t have to depend on human bodies or animal bodies to grow. So that’s why sanitation infrastructures and other strategies in relation to the environment will also be critical to address the issue of AMR,” he said.
Clinical practice must address emissions
Prof. Liu and the researchers are advocating for a change in strategy responding to AMR, based on their findings.
“In the past, we have been focused on reducing antibiotic consumption, which works. But it’s less effective compared to the adoption of the sustainable development pathway articulated by the United Nations,” he said.
Prof. Liu said that the health care sector — specifically, clinical practice — has a huge effect on global emissions.
“The health industry is one of the top carbon emitters. If it was a country, it would be ranked in the top five in terms of carbon emission. And the majority of the emission – 80% – comes from clinical practice,” he said.
Prof. Liu said the researchers suggest a three-tier approach.
“The first tier is at the individual level: the patient. We understand the individual needs of the patient to provide better service. But we also think about value at the second level – the population level,” he said.
“One of the examples is encouraging vaccination. By receiving vaccination, it’s not only beneficial to the individual, but we will also be able to provide herd immunity,” he said.
“The third tier is the planet, and climate change. And we also need to consider values to the planet for several reasons,” he said.
“The health industry is one of the top carbon emitters, because we are using medicines and products coming from all over the world. And the manufacturing process and the supply chain emit huge amounts of greenhouse gas emissions,” he said.
Prof. Liu said that the Deeble Institute recently published a report advocating for changes in health technology assessment, incorporating value assessment to the planet.
“If we move towards the upstream of interventions, social prescriptions or preventive medical practice, we will be able to reduce the carbon footprint in medical practice,” he said.
“And that’s the only way to move forward. It’s how clinical medicine can attack this problem,” said Prof. Liu.
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