A domestic research team has found the reason why the use of antibiotics has a negative impact on intestinal bacteria. Antibiotics caused mutations in beneficial bacteria in the gut, leading to loss of function.
Professor Kim Hee-nam of Korea University's Department of Bio-Systems and Biomedical Science noted the research results on the 11th, stating that mutations are occurring in gut bacteria exposed to antibiotics, which may increase the risk of metabolic diseases. This study was published in the international journal "Microbiome" on the 8th.
Previously, research only confirmed that the use of antibiotics reduces the number of gut bacteria. The problem is that the simple reduction of bacteria could not explain why the damaged intestinal environment after antibiotic use does not recover over time. Additionally, there were phenomena that could not be explained, such as the non-proportional relationship between antibiotic dosage and the reduction of bacteria.
The research team analyzed the changes that occur when Akkermansia muciniphila is exposed to the antibiotic penicillin. Akkermansia is a beneficial bacterium that resides in the colon and plays an important role in alleviating chronic diseases such as obesity, diabetes, and fatty liver.
According to the study, Akkermansia adapted to survive antibiotics and acquired mutations. As a result of this process, the host protective ability inherent to beneficial bacteria was diminished. Professor Kim explained in an interview with ChosunBiz, "When exposed to antibiotics, not only does the number of beneficial bacteria in the gut decrease, but there is also a high possibility of mutations occurring, leading to loss of original function. Mutations can impact the intestinal environment for a few years to several decades and may be passed down to descendants."
To verify this, the research team conducted experiments on mice. They administered normal beneficial bacteria without mutations and beneficial bacteria with mutations to separate groups of mice, providing them with the same diet that induces metabolic diseases for five weeks. As a result, the mice with normal beneficial bacteria were protected from obesity and metabolic diseases, while the health of the mice with mutated beneficial bacteria deteriorated rapidly.
Professor Kim noted, "This study only analyzed a single species of beneficial bacteria, but it is likely that such mutation phenomena may widely occur in other bacteria as well. Ultimately, the mutation of beneficial bacteria may be a major cause of the increase in metabolic diseases due to the loss of health-protective functions."
This research also holds potential for early diagnosis and treatment of metabolic diseases. By measuring the mutation rate of beneficial bacteria in the gut, it may predict individual vulnerabilities to metabolic diseases. Additionally, new treatments for obesity and metabolic diseases could be developed by supplementing normal beneficial bacteria.
Professor Kim added, "Simply consuming probiotics will not solve the problem. It is important to supplement with healthy, non-mutated beneficial bacteria," stating that further research will uncover the specific mechanisms by which mutations lead to a loss of function.
References
Microbiome (2025), DOI: https://doi.org/10.1186/s40168-024-02023-4