Antibiotic resistance: gut microbiota steps up

The gut microbiota Digestive disorders Probiotics

Could our gut microbiota be the new cure for antibiotic resistance? A recent study ¹ has shown that a collection of “good” bacteria in the gut may be our best ally against resistant infections.

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Created 20 January 2025

Updated 23 January 2025

Antibiotic-resistant gut infections due to prolonged antibiotic use or chronic inflammatory bowel diseases (IBD (sidenote: IBD Inflammatory bowel diseases are characterized by chronic inflammation of the gastrointestinal tract due to immune system dysregulation. They include Crohn’s disease and ulcerative colitis, which cause inflammatory flare-ups that can require hospitalization in 15% of cases. They have no cure. In 2019, 4.9 million people worldwide suffered from IBD Explore Inserm ) ) are an increasingly common threat, particularly in hospitals. The main culprits: pathogenic bacteria (sidenote: Pathogenic bacteria Bacteria that can cause infectious diseases. The WHO lists 15 families of antibiotic-resistant bacteria that currently pose a threat to human health, classified according to priority:
• Critical priority: includes Mycobacterium tuberculosis, which causes tuberculosis, and the Enterobacteriaceae family (including Escherichia coli and Klebsiella pneumoniae), the source of many hospital-acquired infections.
• High priority: includes other bacteria from the Enterobacteriaceae family, such as Salmonella typhi (typhoid) and Shigella (dysentery), whose resurgence is an issue in low-income countries, as well as Staphylococcus aureus, a major cause for concern in healthcare facilities.
• Medium priority: includes streptococci, which cause infections that pose particular danger to the vulnerable (newborns, the elderly). Explore WHO ) of the digestive tract such as Escherichia coli or Klebsiella pneumoniae. Faced with this resistance, researchers are now exploring an unexpected avenue: using our gut’s “good” bacteria to eliminate the bad bacteria. They have recently identified a particularly effective group of these beneficial bacteria which may provide a natural alternative to antibiotics.

Winning cocktail: the power of good bacteria

Scientists developed a mixture of 18 strains of commensal bacteria (sidenote: Commensal bacteria Bacteria that cohabit peacefully with their host, particularly in the gut. They can benefit the host by boosting the immune system, aiding digestion, or fighting pathogens. ) , dubbed F18-mix, from gut microbiota samples taken from healthy individuals. The mixture was tested in mice and proved remarkably effective in reducing the abundance of Escherichia coli and Klebsiella pneumoniae in the gut, while preserving the gut’s good bacteria.

The secret? F18-mix bacteria eliminate pathogenic bacteria by competing with them to feed on certain sugars in the gut, such as gluconate. Gaining the upper hand, they deprive the harmful bacteria of their food source and prevent them from colonizing the gut.

Antibiotics: several tactics to combat bacteria

Antibiotics are like soldiers in the war against the bacteria responsible for infections. To fulfill orders, they either kill bacteria directly or prevent them from multiplying. They use a range of tactics, depending on the target:

The bacterial wall: this is the bacterium’s armor. Some antibiotics prevent its construction; without its protection, bacteria burst and die.
The cell membrane: some antibiotics cause leaks in this structure covering the bacterium. Loss of the membrane destroys the bacterium.
Protein synthesis: some antibiotics block the production of proteins that serve as building blocks of the bacterium’s functioning. This amounts to shutting down the bacterium’s “internal factory”.
DNA synthesis: the creation of DNA enables bacteria to reproduce. Some antibiotics block DNA production, preventing bacteria from multiplying.
Bacterial metabolism: some antibiotics block chemical reactions essential to bacterial development.

Take note, though: antibiotics only fight against bacteria, and not, for example, against viruses. They should thus be used with care, since otherwise bacteria can learn their tricks and develop resistance, ensuring victory for themselves. ⁴

Antibiotics: what impact on the microbiota and on our health?

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Towards new microbiotic treatments?

F18-mix does not just chase away antibiotic-resistant pathogenic bacteria: the researchers showed that, in mice suffering from inflammatory bowel diseases, such as ulcerative colitis or Crohn’s disease, it also helps alleviate clinical signs of the disease and calms inflammation.

While these results are encouraging, the research remains at the experimental stage. Since the tests were performed on mice, further studies will be required to confirm the efficacy of the treatment in humans. Nevertheless, resistant bacteria should take note: our microbiota could well change the rules of the game, revolutionizing the treatments of tomorrow.

World AMR Awareness Week (WAAW)

World AMR Awareness Week is an annual event run by the WHO from November 18 to 24. The aim of WAAW is to inform healthcare professionals, decision-makers, and the general public about the dangers of antimicrobial resistance linked to the excessive or inappropriate use of antimicrobials. The goal is to preserve treatment efficacy and improve global health by promoting responsible practices. WAAW’s slogan: “Antimicrobials: Handle with Care”.