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Sloths may hold a secret weapon against antibiotic resistance 

In the jungles of Costa Rica, a slow and unassuming creature may hold the key to a pressing global health issue. Researchers have discovered that sloth fur is home to an abundance of organisms, including antibiotic-producing bacteria that could offer a novel weapon against drug-resistant “superbugs.”

Sloths are a fascinating subject for scientific study due to the bustling ecosystem found within their fur. This ecosystem hosts an array of life forms, including insects, algae, fungi, and bacteria. Despite the potential disease risk posed by such a diverse collection of organisms, sloths seem to possess an extraordinary resistance to infection.

Max Chavarria, a researcher at the University of Costa Rica, marvels at the complexity of the sloth’s fur habitat. “If you look at the sloth’s fur, you see movement: you see moths, you see different types of insects… a very extensive habitat,” he told AFP. 

But, Chavarria notes, the sloth’s fur is not a lawless wilderness. “Obviously when there is co-existence of many types of organisms, there must also be systems that control them,” he said.

Curious about the sloth’s infection-proof characteristics, Chavarria and his team collected fur samples from two- and three-toed Costa Rican sloths. Their goal was to uncover the mechanisms that keep these sloths healthy despite the abundant microbial life in their fur. 

The study, published in the journal Environmental Microbiology, revealed the potential presence of antibiotic-producing bacteria that appear to keep pathogenic microbes and other competitors, such as fungi, in check.

Sloths are national symbols in Costa Rica, drawing in tourists with their laid-back lifestyle. They dwell in the hot and humid jungles along the Caribbean coast, living in the canopies of trees. Unfortunately, both the two-toed and three-toed sloth species have seen a decline in their population, according to the International Union for the Conservation of Nature.

Judy Avey, who runs a sanctuary for injured sloths in the heart of the Costa Rican jungle, has firsthand experience with these enigmatic animals. Along with her late husband, Luis Arroyo, Avey has been caring for sloths since 1992, when she received her first one, named “Buttercup.” Since then, she has looked after around 1,000 animals, observing a curious pattern in their health.

“We’ve never received a sloth that has been sick, that has a disease or has an illness,” Avey told AFP. “We’ve received sloths that had been burned by power lines and their entire arm is just destroyed… and there’s no infection. I think maybe in the 30 years (we’ve been open), we’ve seen five animals that have come in with an infected injury. So that tells us there’s something going on in their bodily ecosystem.”

Max Chavarria has identified 20 “candidate” microorganisms that could potentially have antibiotic properties, though much work remains before they can be considered for human use.

“Before thinking about an application in human health, it’s important to first understand what type of molecules are involved,” said Chavarria. He cites the example of penicillin, the world’s first antibiotic discovered by British scientist Alexander Fleming in 1928, which revolutionized medicine and earned him the 1945 Nobel Prize. 

But today, antibiotic resistance has become a growing concern, with some medicines no longer effective in treating the infections they were designed to combat. This natural phenomenon has been exacerbated by the overuse and misuse of antibiotics in humans, animals, and plants. 

The World Health Organization estimates that by 2050, resistance to antibiotics could cause 10 million deaths per year. Chavarria believes that projects like his may contribute to discovering new molecules that could help in the fight against antibiotic resistance.

“Projects like ours can contribute to finding new molecules that can, in the medium or long term, be used in this battle against antibiotic resistance,” said Chavarria. 

More about antibiotic resistance 

Antibiotic resistance is a significant public health concern that occurs when bacteria and other microorganisms develop the ability to defeat the drugs designed to kill them. This resistance makes it harder to treat various infections and increases the risk of disease spread, severe illness, and death.

Microorganisms are naturally adaptable and can evolve to resist the effects of an antibiotic. This is a natural phenomenon known as antimicrobial resistance, and it is accelerated by the misuse and overuse of antibiotics. For instance, when antibiotics are used improperly (such as not completing a prescribed course of treatment) or are overprescribed, bacteria have more opportunities to evolve and develop resistance.

Antibiotic resistance is not confined to any one geographic region or population, and it has the potential to affect anyone, regardless of age or health status. The World Health Organization (WHO) has described antibiotic resistance as one of the biggest threats to global health, food security, and development today.

A particularly concerning aspect of antibiotic resistance is the rise of multidrug-resistant bacteria, sometimes referred to as “superbugs.” These bacteria are resistant to several antibiotics, making infections caused by them extremely difficult to treat. As a result, procedures that rely on effective antibiotics to prevent infections – such as surgeries, chemotherapy, and cesarean sections – become riskier.

Across the globe, efforts are being made to improve antibiotic use, develop new antibiotics, and discover alternative treatments. This includes initiatives to better educate the public and healthcare providers about responsible antibiotic use, as well as ongoing research into new drugs and treatments.


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