Centenarians are less susceptible to age-related chronic diseases and are more likely to survive infectious diseases. As scientists from the Broad Institute at the Massachusetts Institute of Technology and Harvard have found out, people who live for more than a hundred years have a unique microbiome that protects them from bacterial infections, including those that have resistance to drugs. The secret of longevity was revealed in an article published in the journal Nature.
The researchers analyzed the microbiome in the feces of 160 Japanese centenarians, whose average age reached 107 years. They found that centenarians compared to people aged 85 to 89 years and 21 to 55 years had higher levels of several types of bacteria that produce molecules called secondary bile acids. Secondary bile acids are produced by microbes in the colon and are believed to help protect the intestines from pathogens and regulate the body’s immune responses.
One of the molecules, isoalloLCA, effectively inhibited the growth of a microbial culture with the antibiotic-resistant bacterium Clostridioides difficile, which causes diarrhea and intestinal inflammation. Odoribacteraceae bacteria produce this bile acid with the participation of the enzymes 5α-reductase (5AR) and 3β-hydroxysteroid dehydrogenase (3βHSDH). Feeding infected C. difficile mice with a diet supplemented with isoalloLCA also reduced the level of the pathogen in the body.
IsoalloLCA killed many other gram-positive (but not gram-negative) pathogens, including Enterococcus faecium, indicating that the molecule can help the body maintain a delicate balance of microbial communities in a healthy gut. Gram-positive bacteria are called bacteria that are colored blue and do not discolor using the Gram method, and have a thick cell wall. Many pathogenic microorganisms for humans are gram-positive.