Bifidobacterium faecale sp. nov., isolated from human faeces

Area of Science:

• Microbiology
• Gut Microbiome Research
• Bacterial Taxonomy

Background:

• The human gut microbiome plays a crucial role in infant health and development.
• Bifidobacterium species are key commensal bacteria in the infant gut, known for their beneficial effects.
• Understanding the diversity of Bifidobacterium is essential for characterizing a healthy gut microbiome.

Purpose of the Study:

• To isolate and characterize a novel bacterial strain from infant feces.
• To determine the phylogenetic and taxonomic placement of the novel isolate within the Bifidobacterium genus.
• To propose a new species designation based on polyphasic taxonomic analysis.

Main Methods:

• Isolation of bacteria from infant fecal samples.
• 16S rRNA and hsp60 gene sequence analysis for phylogenetic identification.
• DNA-DNA hybridization for genetic relatedness assessment.
• Analysis of cellular fatty acid composition and enzyme activity.
• Determination of DNA G+C content.

Main Results:

• A novel Gram-positive, anaerobic, rod-shaped bacterium, strain CU3-7(T), was isolated.
• Phylogenetic analysis showed highest 16S rRNA gene similarity to Bifidobacterium adolescentis (98.4%) and Bifidobacterium ruminantium (97.9%).
• DNA-DNA hybridization values were below 17%, confirming distinct species status. Key cellular fatty acids and fructose-6-phosphate phosphoketolase activity were identified.

Conclusions:

• Strain CU3-7(T) represents a novel species within the genus Bifidobacterium.
• The proposed name for this new species is Bifidobacterium faecale sp. nov.
• This finding contributes to the understanding of bacterial diversity in the early-life gut microbiome.