[NAIROBI] It is well known that poorer countries bear the biggest burden of resistance to antimicrobial drugs and that these countries are also most vulnerable to climate change.
But little research has been done into the link between these two phenomena.
Now new analysis by Chinese researchers projects the scale of the burden of antimicrobial resistance, or AMR, in low- and middle-income countries under current climate change trajectories, if sustainable development strategies are not urgently pursued.
It found that sustainable development efforts — such as lowering out-of-pocket health expenses, expanding immunisation coverage, increasing health investments and ensuring universal access to water, sanitation and hygiene services — were more effective in tackling resistance than simply reducing antibiotic use.
The study, published in the journal Nature Medicine, projected that AMR — where disease-causing bacteria and viruses no longer respond to the medicines designed to treat them — could increase by up to 2.4 per cent globally by 2050.
In low- and middle-income countries the figure was more than four per cent.
Lead author Lianping Yang, an associate professor at the School of Public Health at China’s Sun Yat-sen University, says the effects of climate change — such as rising temperatures and extreme weather events — can impact all countries.
“However, our study shows that the increase in AMR is projected to be much steeper in low- and middle-income countries,” he told SciDev.Net.
“This is largely because these countries often face greater challenges in healthcare access, public health infrastructure, and overall population health.”
Bacterial AMR was linked to 4.71 million deaths in 2021, according to a previous study in The Lancet. It was found to be directly responsible for an estimated 1.14 million deaths — a figure expected to rise to nearly 2 million deaths by 2050.
However, much of the AMR response has been focused on excessive antibiotic use, and less attention has been given to the context of climate change and socioeconomic conditions, the Chinese scientists say.
By exploring the connections between them, the researchers hope to spur more targeted and efficient strategies that address both challenges at once, especially for low- and middle-income countries.
“When climate-related stresses occur in places with limited clean water, sanitation, and medical services, the risk of infections rises — and so does the reliance on antibiotics, which can accelerate resistance,” explained Yang.
“In short, climate change acts as a multiplier of existing vulnerabilities, making the AMR problem more severe in parts of the world that are already struggling with basic health and environmental protections.”
The researchers analysed more than 4,500 records encompassing 32 million isolates of six key bacterial pathogens (bacteria, viruses, or other microorganisms) resistant to antimicrobials, obtained from 101 countries between 1999 and 2022.
They then used forecasting models to investigate how socioeconomic and environmental factors and policies would influence global AMR trends.
They found that under the worst-case climate scenario, in which global temperatures would increase by 4-5 degrees Celsius by the end of the century from pre-industrial levels, AMR could increase by 2.4 per cent by 2050, compared to a low-emissions scenario.
This varied from 0.9 per cent in high-income countries to 4.1 per cent in low- and middle-income countries.
Yang said low- and middle-income countries in parts of Sub-Saharan Africa, South Asia, and Southeast Asia that are both economically less developed and highly exposed to the impacts of climate change will be more vulnerable.
Perfect storm
“These regions often face a combination of challenges: limited access to clean water and sanitation, under-resourced healthcare systems, and high levels of infectious disease,” he told SciDev.Net.
“When these vulnerabilities are combined with the effects of climate change — such as rising temperatures, floods, and extreme weather — they create ideal conditions for drug-resistant infections to spread.”
He believes addressing these challenges is a global responsibility, not just a local one.
“These countries urgently need greater attention and support for AMR prevention and control, as they are on the frontline of this growing global health threat,” he added.
The researchers called for urgent action to address broader socioeconomic and environmental factors beyond simply reducing antibiotic use to mitigate the global AMR burden.
They suggest that sustainable development strategies could reduce the future prevalence of AMR by 5.1 per cent and surpass the effect of reducing antimicrobial consumption, which is projected to lower AMR prevalence by 2.1 per cent.
Extreme weather
David Graham, an environmental engineer at Durham University, in the UK, said the findings of this study make sense.
“It is very probable climate changes, especially warming, and more extreme and sporadic droughts and floods, will increase AMR transmission and spread,” he told SciDev.Net.
“As temperatures increase, gut pathogens who like warmer temperatures, including AMR strains, will grow more rapidly in the environment and prevail longer, increasing the probability of AMR everywhere.”
He says the problem will be exacerbated by more extreme weather events, such as more intense rainfall and flooding, increasing the uncontrolled spread of water pollutants and diseases.
“The scale of the dataset is impressive,” added Graham, who has developed an AI tool to tackle AMR.
However, he says the analysis neglects to consider a few important factors related to AMR expansion or reduction, such as education, antimicrobial use in food production, and animal farming.
“This work could be enhanced by the use of growing AI and other intelligent search methods, which are able to expand the scale of analysis of examining larger and more complex databases,” he suggested.
This piece was produced by SciDev.Net’s Global desk.
