Foot ulcers are a common complication of diabetes. And in some cases, the bacteria that infect these open wounds don’t respond to treatment with antibiotics, which can leave doctors with no option but to amputate part of the person’s foot or leg.
Now, researchers in England may have discovered a possible solution to this problem—in a rather unusual place. They’re sifting through the poop of zoo animals in search of viruses that can kill the foot ulcer-causing bacteria.
This research may sound gross, but if it’s successful, it has the potential to be applied more broadly and address a pressing medical challenge: drug-resistant superbugs. If left unchecked, these pathogens—which have evolved to evade antimicrobial treatments—could be responsible for an additional ten million deaths each year by 2050.
As bacteria grow resistant to antibiotics, researchers have been searching for other possible options to treat infections. An emerging option is known as phage therapy, which relies on a type of virus known as a bacteriophage. These viruses, called phages for short, can hijack certain bacterial cells and destroy them from the inside out.
Phages take a targeted approach to killing bacteria: Each can typically only kill one or several bacterial strains. This means that the more phages scientists can discover, the more bacterial strains they could have a possible weapon against.
With this in mind, researchers at the University of Sheffield decided to go poking around in the dung of several animals at Yorkshire Wildlife Park, located northeast of Sheffield in central England. The 260-acre wildlife conservation and rehabilitation center has more than 70 species in its care, including several endangered ones.
Graham Stafford, the microbiologist spearheading the project, dreamed up the idea of looking for phages in animal dung during a visit to the wildlife park with his family. So far, his team has isolated phages from the feces of Guinea baboons, lemurs, Visayan pigs, giraffes and carnivorous mammals called binturongs.
“Despite the smell, it turns out that the fecal matter of endangered species could hold the key to killing infectious bacteria that are otherwise resistant to antibiotics,” he says in a statement. “It provides an ever stronger reason to conserve endangered animals. The biodiversity they harbor potentially includes new cures for a range of infectious diseases, and we believe this is the tip of the iceberg in this area.”
To isolate phages, the researchers add water to a poop sample and mix it into a slurry. Then, they filter the concoction until just the phages remain. Placing each phage in a lab dish, they add various types of bacteria to determine which ones the phage can infect. They also study each phage’s DNA and take microscopic images to see how it compares to known phages, per Live Science’s Nicoletta Lanese.
Previously, the team looked for phages in the feces of farm animals like chickens and cattle, as well as in human mouths. With their work at the wildlife park, they’re on the hunt for phages that can specifically help treat diabetic ulcers, which approximately 75,000 patients in England receive treatment for each week, according to the statement. Those infections result in some 7,000 amputations each year.
Foot ulcers are also a big problem elsewhere around the world. In the United States, for example, they afflict 15 percent of the 37.3 million Americans with diabetes. And of those Americans that develop foot ulcers, an estimated 14 to 24 percent must undergo an amputation, per the Cleveland Clinic.
These ulcers occur because of a common diabetes complication called neuropathy, which can cause patients to lose feeling in their feet. If a diabetic patient with neuropathy accidentally cuts or scrapes one of their feet, they may not feel the wound, which, in turn, can become infected. If the wound does not respond to antibiotic treatments, doctors may need to eventually remove the affected limb.
If the team’s research pans out, doctors may one day be able to apply phages to these drug-resistant wounds. In the United Kingdom, this could ultimately result in roughly $1.2 billion (£1 billion) in healthcare savings each year, per the statement. Right now, the animal feces phage research is still in its infancy; the scientists working on this project have not yet undertaken clinical trials or published any papers about their findings. However, separate clinical trials for phage therapy for diabetic foot ulcers are underway.
And for anyone who’s squeamish, Stafford points out that they’re not “going to take poop and put it on people’s feet,” as he tells Live Science. Rather, the phages will be purified, grown in a lab and, eventually, made into a product “like a medicine or an ointment,” he tells the publication.