Researchers have discovered that using antibiotics repeatedly can lead to weaknesses in the gut’s protective mucus barrier. This results from changes in the gut microbiota driven by the antibiotics. Additionally, they identified a separate mechanism through which antibiotics can directly harm the mucus barrier without involving bacteria.
A team from UmeĆ„ University and Tartu University has established that repeated antibiotic use can damage the gut’s protective mucus barrier due to changes in the microbiota influenced by antibiotics. In another study, they uncovered a mechanism that allows antibiotics to directly harm the mucus barrier without the involvement of bacteria.
The findings were published in the scientific journals Gut Microbes and Science Advances.
āThese two studies indicate that antibiotics can harm the mucus layer through at least two different mechanisms and may have long-term effects due to changes in gut bacteria. This strongly emphasizes the need for responsible antibiotic use,ā explains Bjƶrn Schrƶder, a Docent in Infection Biology at UmeĆ„ Universityās Department of Molecular Biology.
Although antibiotics are critical for treating bacterial infections, their overuse or misuse poses significant health risks, particularly concerning gut health. Previous studies highlighted the short-term effects of antibiotic treatments on gut health, but the impacts of prolonged antibiotic use over the years remain less understood.
To explore this issue further, Bjƶrn Schrƶder and his team at UmeƄ University collaborated with researchers at Tartu University in Estonia, who created a well-characterized group of individuals that provided stool samples and health data.
The researchers focused on individuals who had taken at least five antibiotic courses in the past but had not taken any within six months prior to stool collection. They compared the microbiota of these individuals to those who had not used antibiotics in the last ten years.
āOur analysis uncovered changes in the composition of gut bacteria, even though the antibiotics were taken a considerable time ago. The findings suggest that repeated antibiotic use leads to lasting changes in the microbiota that can persist for months after the last antibiotic treatment,ā states Kertu-Liis Krigul, a PhD student at Tartu University.
After transferring human microbiota into mice and employing specific methods to study mucus function in the gut, the researchers observed that the mucus layer’s function was compromised in mice receiving microbiota from individuals with a history of frequent antibiotic use. There was a reduction in mucus expansion, and the mucus layer became permeable, allowing bacteria to approach the intestinal lining.
āBy analyzing the bacteria in the gut in detail, we discovered that certain bacteria, which are known to consume the mucus layer, were present in greater numbers in these mice. This reinforces the idea that gut bacteria play a crucial role in maintaining the functionality of the mucus barrier,ā remarks Rachel Feeney, a PhD student at the Department of Molecular Biology at UmeĆ„ University.
A separate international study further demonstrated that antibiotics can disrupt the mucus barrier directly, independent of gut bacteria.
By administering the antibiotic vancomycin to regular and ‘bacteria-free’ mice, the researchers showed that this antibiotic can directly impact the mucus barrier without involving gut bacteria. Additional experiments with intestinal tissue at UmeĆ„ University confirmed that the antibiotic could disrupt mucus expansion within minutes of application.
Facts: Our gut bacteria
Gut bacteria are vital for proper digestion and immune system training. However, their activities must be carefully regulated to protect our health. The intestines are coated with a continually rejuvenating mucus layer that typically prevents bacteria from penetrating it. Disruptions in the gut environmentādue to diet changes or antibiotic usageācan impair the mucus barrier’s function. This situation allows bacteria to reach the intestinal lining, potentially leading to inflammation and increasing the risk of diseases such as IBD.
Some gut bacteria “consume” elements of the mucus barrier, physically thinning it. While this is normal in small amounts within a healthy gut, excessive consumption can compromise the mucus barrier’s effectiveness.
