# Culture-based studies of intestinal lactobacilli in young people and centenarians

## TL;DR

This study compares gut lactobacilli in centenarians and young adults, finding unique metabolic traits in centenarians that may support healthy aging.

## Contribution

The study identifies distinct lactobacilli species and metabolic profiles in centenarians, suggesting potential probiotic candidates for longevity.

## Key findings

- Centenarians had 12 unique lactobacilli species and higher species richness compared to young adults.
- Lactobacilli from centenarians showed distinct carbohydrate fermentation and higher levels of acylcarnitines and bile acids.
- The findings suggest functional adaptations in centenarian lactobacilli that may support healthy aging.

## Abstract

Biological ageing is associated with physiological changes, including alterations in the gut microbiota. Lactobacilli may contribute to host health and longevity, yet their composition and functional properties in centenarians remain poorly characterized. The present study aimed to compare cultured intestinal lactobacilli from centenarians and young adults and to identify strains with potential probiotic properties.

Fecal samples were obtained from centenarians (n = 25) and young adults (n = 25). Lactobacilli were isolated using culture-based methods and identified to the species level. Antibiotic susceptibility testing was performed for all isolates. Biochemical and metabolic properties of antibiotic-sensitive strains were determined.

Twenty Lactobacillus species were identified. Six species were shared between groups, 12 were unique to centenarians, and two to young adults. Although overall Lactobacillaceae abundance was similar, centenarians showed greater species richness and a higher relative proportion of lactobacilli. Isolates from centenarians exhibited distinct carbohydrate fermentation patterns and metabolic profiles, including higher levels of acylcarnitines, arachidonic acid, and selected bile acids.

Lactobacilli isolated from centenarian demonstrate distinct compositional and metabolic characteristics compared with those from young adults. These differences may reflect functional adaptations potentially relevant to healthy ageing and could inform the selection of candidate strains for future probiotic development.