Ärzte entwickeln derzeit ein "super neues Medikament", das aus gefriergetrocknetem menschlichem Kot in Kapseln verpackt wird und zur Behandlung verschiedener hartnäckiger Krankheiten dienen soll.

Thanks to freeze-drying technology, we can brew strong coffee outdoors and make orange juice with pulp in the office. As freeze-drying technology enters the medical field, in the future, we may even be able to recreate fresh... feces at home without leaving the house.

Don't laugh just yet. This is really a serious study!

In the UK, a scientific research team is trying to use freeze-dried feces to address the threat that pathogen resistance poses to human health.

Freeze-drying technology is a method that freezes materials and then allows the ice to directly sublimate into water vapor in a vacuum environment, achieving dehydration and drying of the materials (Image source: empire freezing drying).

When we get sick due to a bacterial infection, we sometimes use antibiotics for treatment. However, during the treatment process, the pathogenic bacteria may undergo genetic mutations, rendering antibiotics ineffective against them. This is what is known as bacterial resistance. When a pathogenic bacterium is resistant to multiple antibiotics at the same time, it becomes what doctors call a "superbug".

Many superbugs reside in the human gut. When other bacteria are decimated by antibiotics, superbugs "shine alone" due to their resistance and become increasingly stronger. This leads to patients' illnesses being difficult to cure, recurring, and even becoming untreatable in the end.

This is a small freeze-dryer. Scientists are drying fungal spore reagents (Image source: Wikipedia by Susato).

When it seemed like there was no solution, scientists discovered that a healthy gut microbiota system can inhibit the growth of superbugs and keep them at a relatively safe level. So, how can we implant a normally functioning gut microbiota into patients?

Scientists set their sights on the feces of healthy people.

Feces for treating diarrhea

The seemingly strange idea of freeze-dried feces is not without reason. Its origin can be traced back to the "fecal microbiota transplantation" that emerged more than a decade ago when treating Clostridium difficile infection.

In early 2009, 79-year-old Marion went to a hospital in Rhode Island, USA, because she had diverticulitis. The doctor prescribed several courses of antibiotic drugs for her. After taking the medicine for a few weeks, Marion started having severe diarrhea. After diagnosis, the doctor found that she was unfortunately infected with Clostridium difficile.

Clostridium difficile in a fecal sample (Image source: Wikipedia by CDC).

Clostridium difficile (hereinafter referred to as C. difficile) is originally a normal member of the human gut microbiota. However, when antibiotics are used inappropriately, it may lead to an imbalance in the gut microbiota, and C. difficile may multiply in large numbers. The main symptoms of C. difficile infection are diarrhea and enteritis. In severe cases, patients may even need to use a wheelchair and wear adult diapers.

Marion had to start treating the new illness. So, the doctor prescribed several courses of commonly used broad-spectrum antibiotics for her. At the beginning of taking the medicine, the diarrhea did improve, but a few days after stopping the medicine, the symptoms reappeared. After going back and forth to the hospital four times, the doctor told Marion that he had exhausted all methods and suggested that she talk to Colleen Kelly from the Warren Alpert Medical School of Brown University.

Vancomycin and fidaxomicin are commonly used antibiotics for treating C. difficile infection (Image source: Internet).

At that time, Colleen was trying a new method to treat C. difficile infection.

She told Marion that the beneficial bacteria in the human gut maintain a delicate balance, preventing pathogenic bacteria from getting out of control. When antibiotics are used, this balance is temporarily disrupted but usually recovers on its own after a while. Marion's gut microbiota lost the ability to recover automatically. So, the feces of a healthy person can be diluted and implanted into her gut to rebuild a healthy gut environment. This method is called fecal microbiota transplantation.

Marion, who was troubled by the illness, decided to give it a try and chose her 49-year-old son as the donor. Colleen first confirmed that the collected feces met the hygiene standards, then diluted it, and used a colonoscopy device to inject the fresh feces into Marion's gut. Two days later, Marion's diarrhea stopped and never recurred.

Actually, by the time Marion recovered, some doctors had already started using fecal transplantation to treat C. difficile infection. However, due to the lack of serious research on this method at that time, many medical staff were skeptical about it or simply found it disgusting.

In 2013, the New England Journal of Medicine published the first randomized controlled trial on fecal transplantation, proving its effectiveness. Among the 16 patients who received fecal transplantation, 13 were cured after one transplantation, and 2 were cured after two transplantations. The effective rate reached 94%, far exceeding that of antibiotic therapy.

A general diagram of the fecal microbiota transplantation process (Image source: MDPI).

Subsequently, as more and more experimental results were announced, the medical regulatory agencies in countries such as the UK, the US, and France successively approved fecal transplantation therapy. Feces began to have medical value.

Feces against superbugs

Although C. difficile is a native inhabitant of the human gut, in some aspects, it is very similar to superbugs that are resistant to multiple antibiotics. Many superbugs reside in the gut, and when they accidentally leave the gut, they may also cause urinary tract or blood infections. Therefore, removing superbugs from the gut is undoubtedly the best preventive and therapeutic method.

A research team from the UK was inspired by fecal microbiota transplantation and wondered if a similar method could be used to address the threat that pathogen resistance poses to human health. This research was published in the Journal of Infection in July.

The new study recruited a total of 41 subjects who had all been infected with superbugs in the past six months. Among them, 20 people in the control group took a placebo, and 21 people took freeze-dried feces capsules.

The source of the freeze-dried feces is a specialized "fecal bank". The researchers first tested each piece of feces to ensure that it did not contain any harmful microorganisms, then removed the undigested food residues from the feces, and finally turned them into powder through freeze-drying technology and encapsulated them. The shell of this capsule can survive the stomach and only begins to dissolve after reaching the gut.

The freeze-dried feces capsules used in the experiment (Image source: GSTT).

The results showed that although the content of superbugs in the guts of both groups of subjects decreased, the decrease in the "freeze-dried feces group" was more prominent. In addition, compared with before the experiment, the gut microbiota of the subjects who took the freeze-dried feces became more diverse. This means having a stronger resistance to pathogens. One month later, the bacteria of the donor could even be detected in their guts.

Blair Merrick, one of the authors of the article, believes that the small-scale success of this experiment lays a good foundation for larger-scale research in the future. If large-scale experiments also confirm the effectiveness of freeze-dried feces, it may bring a breakthrough change to the treatment and prevention of superbugs.

Blair Merrick, the lead author of the article and a researcher at Guy's and St Thomas' NHS Foundation Trust (Image source: Internet).

Personally, I think the most successful aspect of this new experiment is the freeze-dried feces. After all, the previous fecal transplantation was a bit too "direct": the feces needed to be transplanted within six hours; the liquid state was inevitably nauseating; and some institutions even used a nasal catheter to inject fresh feces into the gut, although the catheter was airtight and there was no smell...

However, a survey of 162 patients changed my view. When only considering the efficacy, 85% of the respondents (138 people) chose to accept fecal transplantation. When they were told that the essence of this method was to accept fresh feces from a stranger, only a few 16 people switched to using antibiotics.

It is estimated that in 2050, 1.91 million people will die from antibiotic-resistant infections globally each year (Image source: Internet).

Indeed, when suffering from a long-term illness, as long as there is hope of recovery, people are probably willing to take a chance. In the face of life, any difficulty seems insignificant.

If necessary, would you be able to accept freeze-dried feces?

References

[1]https://www.journalofinfection.com/article/S0163-4453(25)00098-2/fulltext

[2]https://www.scientificamerican.com/article/swapping-germs/

[3]https://www.wired.com/2013/01/fecal-clinical-trial/

[4]https://www.bbc.com/news/articles/clyge290l4xo

[5]https://theweek.com/health/poo-pills-and-the-war-on-superbugs

This article is from the WeChat public account "Bring Science Home" (ID: steamforkids), author: Liu Liuqi, proofreader: Ziv. It is published by 36Kr with authorization.