B. infantis Provides Benefits to the Microbiome without Using Antibiotics to Kill Existing Microbes
Many adults suffer from disorders related to imbalances in their gut microbiome, such as Crohn’s disease and inflammatory bowel disease. Even neurodevelopmental disorders like autism have been linked to gut microbiome imbalances. Finding ways to introduce new, helpful bacteria to support the gut can be challenging without antibiotics, which remove all bacteria. Depletion of all bacteria allows unhealthy shifts to occur in the gut since the microbiome is resistant to colonization. As widely recognized, human breast milk naturally contains bacteria known to have positive influences on the microbiome. Recently, an innovative study has explored the possibility of reintroducing Bifidobacterium infantis (B. infantis) into adults with an imbalanced gut microbiome (gut dysbiosis). B. infantis is a friendly gut microbe found in human breast milk. The current study’s authors discovered that they could introduce B. infantis into healthy adult microbiomes without using antibiotics to kill off existing microbes. Along with B. infantis, the researchers also used human milk oligosaccharides (HMO), which feed microbes that live within the gut. They discovered that as long as HMO was continuously provided to these healthy adults, B. infantis joined their microbial community or “engrafted,” at tremendously high levels. After the HMO was removed from the subjects’ diet, B. infantis disappeared, showing that none of the therapeutic microbe remained. This situation is similar to when infants are weaned from human milk. Never before has a study shown that engraftment (and conversely, de-engraftment) of a target microbe in a healthy adult could be controlled. The research team took their work a step further and recapitulated their results in a mouse model. The authors also presented evidence in their study that B. infantis can feed other beneficial members of the microbial community, leading to the production of butyrate–a molecule made in healthy microbiomes that both trains the immune system and improves gut barrier function. In the future, the team believes that the introduction or reintroduction of B. infantis and HMO may have the potential to treat individuals with diseases that are influenced by an imbalance in the gut microbiome.
