Differences in the Distribution of Bifidobacterial and Enterobacterial Species in Human Faecal Microflora of Three Different (Children, Adults, Elderly) Age Groups

Abstract

To determine if there is any change with age in the distribution of Bi dobacterium and Enterobacteriaceae species in human intestinal micro ora, strains were isolated from a total of 54 samples of human faeces (15 children, 3-15 years old; 17 adults, 30-46 years old; 22 elderly, 69-89 years old). The bi dobacteria were identi ed at species level using a numerical phenotypic identi cation system developed on the Internet (http:::kounou.lille.inra.fr) and DNA-DNA hyridization. The enterobacteria were identi ed using the API 20E system (Biomérieux, France). Escherichia coli was present in 93% of samples. Enterobacter and Klebsiella species were more frequently found in children while Proteus and Pro×idencia species were typically found in the elderly. The species Bi dobacterium longum was the most frequently species isolated in children and adults, whereas Bi dobacterium adolescentis was the most encountered species in the elderly. The distribution of B. adolescentis was signi cantly split between the children and the elderly age groups. There is a noticeable trend whereby Bi dobacterium pseudocatenulatu m occurs more frequently in children than in the elderly. The species Bi dobacterium infantis, Bi dobacterium gallicum and Bi dobacterium angulatum have never been isolated, while Bi dobacterium bre×e has only been isolated on one occasion.

Quantification of Human Fecal Bifidobacterium Species by Use of Quantitative Real-Time PCR Analysis Targeting the groEL Gene

“…infantis) were frequently found in feces from breast-fed infants, suggesting that these three species play a crucial role in gut colonization (16,30,39). In accordance with previous studies (15,37,38), B. longum was the most common species in human adult feces, followed by B. adolescentis, B. bifidum, and B. pseudocatenulatum. A high incidence of B. longum, B. adolescentis, B. bifidum, and members of the B. catenulatum group was observed in Japanese adults (29,30).…”

“…At 2 years of age, when the complex gut microbiota is fully established, the proportion of fecal bifidobacteria decreases to 1 to 3% (41). Even lower levels or absence of bifidobacteria have been reported for the elderly (3,15,19,38).…”

Probiotic cheese containing Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus NCFM® modifies subpopulations of fecal lactobacilli and Clostridium difficile in the elderly

“…In addition, increasing evidence suggests that aging is associated with alterations in the gut microbiota (Bartosch et al 2004;Biagi et al 2010;Gavini et al 2001;Hopkins et al 2001;Hopkins and Macfarlane 2002;Mueller et al 2006;Woodmansey et al 2004). Moreover, elderly subjects living in hospitals and nursing homes are susceptible to increased pathogen challenges.…”

Molecular Identification and Anti-pathogenic Activities of Putative Probiotic Bacteria Isolated from Faeces of Healthy Elderly Individuals

“…According to API identification these isolates were classified as Bifidobacterium spp., B. longum or B. bifidum . This is in contrast with most previous studies on the specific composition of bifidobacteria within the elderly, where B. adolescentis was reported as the most common Bifidobacterium species (11,33,34). However, these studies relied upon phenotypic identification techniques and not 16S rDNA sequencing.…”

“…Gavini et al (11) determined the changes in the Bifidobacterium species by DNA Á/DNA hybridization in three different age groups and concluded that B. adolescentis was the most frequently isolated species in the 22 elderly subjects examined, whereas B. longum was the most frequently encountered species from 15 children and 17 adults. Using microbial culture techniques combined with molecular typing, Kimura et al (35) observed that each of the 10 human subjects studied harboured a unique collection of bifidobacteria and lactobacilli, at least for the numerically predominant strains.…”