Climate change fuels the rise of global antimicrobial resistance

The world is in trouble – have you ever considered that it’s not just rising temperatures and natural disasters we need to worry about? Climate change has a sinister accomplice: antimicrobial resistance (AMR), and together, they’re a dangerous pair.

AMR refers to the increasingly worrisome trend of bacteria, viruses, fungi, and parasites evolving to resist the very drugs designed to kill them.

Climate change drastic impacts

Climate change is known as the threat multiplier for AMR. It has widespread effects that are making our superbug problem significantly worse. Here’s how climate change is linked to antimicrobial resistance:

A warmer world means more illness

Many disease-causing bacteria and other microbes have historically been limited by geography. Cooler temperatures prevented them from spreading extensively. Climate change disrupts these barriers.

Warmer temperatures allow these pathogens to survive further north or south of their original ranges, and at higher altitudes.

This means that diseases once confined to specific regions could emerge in new areas, posing risks to populations that may not have prior immunity or established medical protocols for treatment.

Stressed ecosystems breed superbugs

Disrupted water systems caused by extreme weather events, such as floods or droughts, can lead to contamination with sewage, agricultural runoff, or other sources carrying drug-resistant microbes.

This contaminated water can then spread these microbes to humans, animals, and crops, increasing the risk of infection and disease.

Additionally, changes in animal agriculture practices, often driven by the need to adapt to extreme weather, can lead to overcrowding or unsanitary conditions.

This creates a breeding ground for drug-resistant microbes to evolve and spread rapidly within animal populations.

More infections, more antibiotics, more resistance

Climate change disrupts ecosystems and weather patterns, leading to several consequences that can increase the spread of diseases caused by various microbes. Warmer temperatures, for example, can allow microbes that thrive in warmer environments to expand their geographic range.

Additionally, extreme weather events like floods and droughts can disrupt water systems and sanitation infrastructure, creating ideal breeding grounds for microbes. These factors contribute to a rise in the number of infections and outbreaks of diseases.

The natural response to this increase in illnesses is often an increased reliance on antibiotics, powerful drugs that target and kill specific microbes. However, this increased use of antibiotics creates a selective pressure on the microbial populations.

As with any population under pressure, some microbes will develop adaptations that allow them to survive antibiotic exposure. These adaptations are the mechanisms of antibiotic resistance.

Real-world effects of climate change on antimicrobial resistance

Climate change is about subtle shifts at the microbial level that are already having serious impacts on our health. The examples below are a snapshot of what could become a widespread crisis.

Bacteria

Bacteria like Campylobacter and Salmonella, responsible for a significant number of food poisoning cases, are flourishing in warming water. Water systems in homes, food processing, and the environment at large are becoming more hospitable.

Contaminated water means these bacteria spread more easily. They can end up on fresh produce, in meat and poultry during processing, and even in drinking water. The warmer the water, the more these bacteria multiply, increasing our risk of getting sick.

Fungus

Candida auris, previously not a major issue for humans, has emerged as a serious threat. One reason is its newfound ability to tolerate warmer and saltier conditions, likely an adaptation driven by the environment changing due to climate change.

This fungus is highly drug-resistant and can cause severe infections, particularly in already-sick patients. As the world warms and coastal areas change, this fungus could become much more common, posing risks to hospitals and people with weakened immune systems.

World threat

Regions with rising average temperatures are also seeing more infections caused by antibiotic-resistant strains of E.coli. This correlation, if seen elsewhere in the world, would mean serious trouble. Infections that were once easy to treat may become a major health challenge.

“Climate change compromises the ecological and environmental integrity of living systems and enables pathogens to increasingly cause disease. The impact on water systems, food-producing animals and crops threatens global food supply,” explained Professor Sabiha Essack, South African Research Chair in Antibiotic Resistance and One Health at the Antimicrobial Research Unit, University of KwaZulu-Natal.

“Human activities associated with population growth and transport, together with climate change increases antibiotic resistance and the spread of waterborne and vector- borne diseases of humans, animals and plants,” Essack concluded.

Melting ice from climate change drives antimicrobial resistance

Professor Essack’s research raises a critical point: as our planet warms, sea levels are rising at unprecedented rates. This isn’t just a threat to coastal communities; it also unlocks a hidden danger – the thawing of permafrost.

Permafrost is permanently frozen ground, mostly in the Arctic regions, that has been like a giant natural deep freezer for millennia.

Melting permafrost releases previously frozen soil, organic matter, and even trapped organisms. These organisms, including ancient microbes, have been entombed for vast stretches of time.

Some of these microbes may carry genes for antibiotic resistance, genes they never needed in their frozen state but which could now pose a serious threat.

The released microbes and their antibiotic resistance genes can travel far and wide. Ocean currents can carry them across vast distances, potentially introducing them to new ecosystems.

Even ships can act as unintentional transporters, carrying microbes in ballast water (water taken on board to ensure stability) that is then released in different ports.

The emergence of antibiotic-resistant microbes from permafrost adds another layer of complexity to the already concerning issue of AMR.

These ancient microbes may have unique resistance mechanisms, posing new challenges for our existing antibiotics. This further emphasizes the need for international collaboration and research to address this evolving threat.

While rising sea levels grab headlines, the hidden consequences of permafrost thaw are a stark reminder of the interconnectedness of our planet. Climate change disrupts these delicate natural systems, and the consequences can be far-reaching and long-lasting.

Halting climate change and antimicrobial resistance

Climate change alone is bad enough, but how we respond to it exacerbates the AMR crisis. Population growth, increased travel, and shifts in agriculture in response to disasters lead to more disease transmission and inappropriate use of antibiotics.

“Climate change has facilitated movement and proliferation of AMR. To deal with this threat, we will need unequivocal political leadership and commitment; strong global and local policy frameworks and governance; evidence-based, innovative ‘One Health’ solutions, and implementation research to adapt successful interventions to country contexts,” explains Prof Essack.

“These partnerships must include a wide range of societal interests that will suspend interests of individual sectors for the public good. Initiatives that aim to make progress in climate change or AMR should join forces and highlight each other to make clear their mutual benefits,” she concluded.

It sounds dire, but it doesn’t mean we’re powerless. Calling on our leaders to prioritize climate action and support the “One Health” approach (which recognizes the interconnectedness of human, animal, and environmental health) are crucial steps.

Dealing with both climate change and antibiotic resistance isn’t going to be easy, but it’s time we all woke up to this interconnected threat. Understanding the problem is the first step toward finding those smart, innovative solutions we need.

The study is part of ESCMID Global Congress (formerly ECCMID) Barcelona, 27-30 April.

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