A new UN Environment report calls for more attention to be focused on the environmental factors fostering the development of strains of drug-resistant bacteria immune to all known antibiotics, known as “superbugs”. By 2050, the UN estimates that up to 10 million deaths could be caused by superbugs and associated forms of antimicrobial resistance, matching the annual global death toll of cancer.

WHO has estimated that some 4.9 million deaths annually are associated with antimicrobial resistance (AMR), while a 2022 Lancet study found that in 2019, 1.27 million deaths – including 860,000 in Africa – were the direct result of drug-resistant bacterial infections. That same year, Africa saw 640,000 deaths from HIV. 

While most attention to AMR has been focused on the use of anti-microbial drugs in the health care and animal husbandry sector, the report highlights growing evidence that the environment is a significant factor in AMR’s growth, transmission, and spread. 

Antimicrobials – which include antibiotics, antivirals, antiparasitics and antifungals – are critical to the health of humans and the livestock, aquaculture, and crops the global food chain relies on. Their discovery in 1928 led to a revolution in medicine that brought about a new era of food security and health now taken for granted.

But their overuse in the pharmaceutical, agricultural and healthcare sectors, and resulting spillover into the environment, is threatening to undermine their effectiveness altogether. As human-made antimicrobials spillover into rivers, soil, and other natural reservoirs, bacteria learn to ‘resist’ treatments to which they were previously vulnerable.

“We are confronted by a silent, slow-motion pandemic,” Mia Amor Mottley, President of Barbados, said at a press briefing marking the launch of the report, held on the sidelines of the Sixth Meeting of the Global Leaders Group on Antimicrobial Resistance in Bridgetown, Barbados. “Our greatest fear is that [AMR] may well become the leading cause of death in the world.”

Climate change and pollution are media for superbug spread

The report calls attention to both global warming and the increased pollution of rivers, lakes and other waterways, which provide condusive environments for drug resistant pathogens to breed and spread. 

“The climate crisis and AMR are two of the most complex threats the world currently faces,” the report said. “Both have been worsened by, and can be mitigated by, human action.”

The UNEP report is the first to call for a “One Health” response to AMR, highlighting the relationship between extreme weather events, higher temperatures, and land-use changes and the spread of resistant bacteria. 

As temperatures increase around the globe, the evolution of resistant bacteria accelerates. In addition, extreme weather events, like floods, lead to the mixing of pathogens from diverse sources, exacerbating the spread of resistant bacteria in places where they did not exist previously, the report stated. 

Of special concern is the pollution of waterways by hospital wastewater, run-off from pharmaceutical production, and agricultural treatments, which contribute to the development and spread of resistant microorganisms in the environment. 

Wastewater and other effluents discharged by such industries are often highly contaminated with antibiotics and other chemicals used to protect or treat people, livestock and plants. When the contaminated waste is discharged, without adequate treatment, it creates an ideal medium for drug resistant bacteria and viruses to grow and flourish. 

This is a particularly large problem in burgeoning cities, which lack adequate wastewater management.  Low and middle income countries, particularly in Asia and South East Asia, are expanding their industrial agricultural production of plants and livestock – which often involves heavy drug and chemical applications  – without adequate effluent treatment.

“The same drivers that cause environmental degradation are worsening the antimicrobial resistance problem,” said Inger Andersen, Executive Director of the UN Environment Programme, at a launch of the report on Tuesday. “The impacts of antimicrobial resistance could destroy our health and food systems.”

Reduction of antimicrobial use is possible, but funding and planning are needed 

While a 2020 study estimated that the use of veterinary antimicrobials will increase by 11.5% by 2030, several countries have already undertaken successful national action plans to reduce the use of antimicrobials across the board. 

The Netherlands achieved a 68% decrease in antimicrobial use over a 10-year period after implementing a comprehensive action plan in 2008. The United Kingdom also reported a decrease in antimicrobial use in animals by 39.2% after publishing its “Five-Year Antimicrobial Resistance Strategy” in 2013. 

But as the global population expands, and financial resources to address AMR remain scarce, low- and middle-income countries will require support to ensure their agricultural industries do not follow the industrialized farming path charted by high-income countries now seeking to redress the negative impacts of antimicrobial use. 

“We need to be able to mobilize far more expansive resources globally if small countries are to play their part in ensuring that the planet that we live on remains safe,” Mottley said, adding that middle-income nations vulnerable to climate shocks should also be supported. 

Currently, 150 countries around the world have national action plans relating to AMR, but just 40 have been implemented. If the rest are not implemented, the risk of AMR getting out of control may become an inevitability. 

“It’s a big ask, but it’s a big problem,” said Dr. Haileyesus Getahun, Director Global AMR Coordination at WHO, who spoke at the publication’s launch. “Unless we step up to the plate, we’re going to have problems not just now, but for generations to come.”

AMR death toll may catch up to cancer by 2050

Antimicrobial resistance is listed by the WHO as one of the top 10 threats to global health, and its impacts are already taking a significant toll on the health of humans, animals, plants, and economies. 

If the development and spread of AMR continues at its current rate, modern medicine will struggle to treat even mild infections among humans, animals, and plants, with devastating consequences, scientists predict.

“We are here because antimicrobials are a super weapon,” UNEP’s Andersen said at a press conference accompanying the launch of the report on Tuesday. “But their effectiveness is under threat. Scattergun and careless use of this super weapon is increasing the emergence of antimicrobial resistant superbugs.” 

The report estimates knock-on effects from AMR could result in at least $3.4 trillion in annual economic damage by 2030, pushing 24 million more people into extreme poverty in the next decade.

“In a world profoundly skewed in favour of wealthy nations and communities, AMR will hit the most vulnerable the hardest. Poverty, lack of sanitation and poor hygiene make AMR worse,” Andersen said. “If we are serious about increasing equity and saving lives, we must act now on AMR.”

Image Credits: Balasaheb Pokharkar.