Blautia hominis 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 health and disease.
• Identification and characterization of novel bacterial species are essential for understanding microbial ecology.
• Diverticulitis is a common gastrointestinal condition associated with alterations in the gut microbiota.

Purpose of the Study:

• To isolate and characterize a novel anaerobic bacterium from a patient with diverticulitis.
• To determine the phylogenetic and taxonomic position of the novel isolate within the genus Blautia.
• To propose a new species designation based on polyphasic analysis.

Main Methods:

• Isolation of strictly anaerobic, Gram-positive coccoid bacterium (strain KB1^T) from human fecal sample.
• 16S rRNA gene sequencing for phylogenetic analysis.
• Physiological and biochemical characterization, including growth conditions, fermentation end-products, and fatty acid composition.
• DNA G+C content determination and Average Nucleotide Identity (ANI) calculation.

Main Results:

• Strain KB1^T showed highest 16S rRNA gene sequence similarity to Blautia producta (97.7-98.9%).
• Phylogenetic analysis placed strain KB1^T within the genus Blautia.
• Physiological tests revealed growth between 15-42°C, tolerance to 20% bile, and production of acetic, succinic, lactic, and fumaric acids.
• ANI value between strain KB1^T and B. producta type strain was 84.1%, supporting distinct species status.

Conclusions:

• Strain KB1^T represents a novel species within the genus Blautia.
• The proposed name for this new species is Blautia hominis sp. nov.
• This finding contributes to the taxonomic diversity of the Blautia genus found in the human gut.