Goal: The aim of this study was to characterize the composition of the intestinal microbiota in healthy centenarians in comparison with younger adults, considering both quantitative and qualitative aspects of gut community structure.
Background: The gut microbiota plays an essential role in human health. Toward seniority, its balance is affected by deep physiological changes. Long-lived people (age >90 y) have unusual features that differ from the younger elderly, so they should be considered separately when analyzing age-related features. However, they have been included in few studies and they have usually been grouped together with the younger elderly.
Study: The gut microbiota of 14 centenarians and 10 younger adults was analyzed. Cultivable bacteria belonging to the following groups were enumerated: enterobacteriaceae, Enterococcus, Staphylococcus, Lactobacillus, Bifidobacterium, Clostridium, Bacteroides, and yeast. Lactobacilli and Bifidobacteria were further characterized at the species level by pyrosequencing.
Results: In centenarians, we observed a reduction in the quantity of enterobacteriaceae, bifidobacteria, and bacteroides and an increase in clostridia sensu stricto (P<0.05). The number of Lactobacillus and Bifidobacterium species isolated in centenarians and younger adults was similar. The composition of the Lactobacillus subpopulation was quite different between the groups. The presence of Bifidobacterium longum in the gut seems to be a particular feature in centenarians. It is interesting to note that only 1 strain of B. longum was isolated from each centenarian subject.
Conclusions: The gut microbiota of centenarians has particular features that differ from both younger adults and the younger elderly. Further studies would help to understand whether the intestinal microbiota can influence life expectancy and whether the administration of probiotic bacteria could help to extend the longevity of human life.