Differences in Fecal Microbiota in Different European Study Populations in Relation to Age, Gender, and Country: a Cross-Sectional Study

TLDR

The study examined 230 healthy adults from France, Germany, Italy, and Sweden, dividing them into 20–50‑year and >60‑year groups, and quantified fecal microbiota using 14 16S rRNA‑targeted probes with fluorescence in situ hybridization and flow cytometry. Country‑age interactions were strongest in Germany and Italy, with inverse patterns for Eubacterium‑Clostridium and Bacteroides‑Prevotella, while Bifidobacterium levels were 2–3× higher in Italians regardless of age, elderly participants had elevated enterobacteria across all sites, and males showed higher Bacteroides‑Prevotella, indicating age‑related microbiota differences vary by population.

Abstract

ABSTRACT A cross-sectional study on intestinal microbiota composition was performed on 230 healthy subjects at four European locations in France, Germany, Italy, and Sweden. The study participants were assigned to two age groups: 20 to 50 years (mean age, 35 years; n = 85) and >60 years (mean age, 75 years; n = 145). A set of 14 group- and species-specific 16S rRNA-targeted oligonucleotide probes was applied to the analysis of fecal samples by fluorescence in situ hybridization coupled with flow cytometry. Marked country-age interactions were observed for the German and Italian study groups. These interactions were inverse for the predominant bacterial groups Eubacterium rectale-Clostridium coccoides and Bacteroides-Prevotella . Differences between European populations were observed for the Bifidobacterium group only. Proportions of bifidobacteria were two- to threefold higher in the Italian study population than in any other study group, and this effect was independent of age. Higher proportions of enterobacteria were found in all elderly volunteers independent of the location. Gender effects were observed for the Bacteroides-Prevotella group, with higher levels in males than in females. In summary, age-related differences in the microbiota makeup were detected but differed between the study populations from the four countries, each showing a characteristic colonization pattern.