Parabacteroides faecalis sp. nov. Isolated from Swine Faeces

Area of Science:

• Microbiology
• Bacterial Taxonomy
• Genomics

Background:

• The genus Parabacteroides comprises anaerobic bacteria found in the gastrointestinal tract.
• Understanding bacterial diversity in animal hosts is crucial for One Health approaches.
• Previous studies have characterized several Parabacteroides species, but novel isolates require thorough taxonomic evaluation.

Purpose of the Study:

• To isolate and characterize a novel bacterial strain from swine feces.
• To determine the phylogenetic, genetic, physiological, and chemotaxonomic properties of the isolate.
• To formally propose a new species within the Parabacteroides genus.

Main Methods:

• Isolation of strain AGMB00274^T from swine feces.
• 16S rRNA gene sequencing for phylogenetic analysis.
• Whole-genome sequencing to determine genome size and G+C content.
• Biochemical tests for metabolic profiling.
• Analysis of cellular fatty acids, respiratory quinones, and polar lipids.

Main Results:

• Strain AGMB00274^T is a Gram-negative, obligate anaerobic, non-motile rod.
• Phylogenetic analysis showed highest 16S rRNA gene similarity (94.9%) to Parabacteroides johnsonii.
• Genome size is 4,308,683 bp with 42.5% G+C content.
• Distinct biochemical profile including positive gelatin hydrolysis and α-fucosidase.
• Dominant fatty acids include anteiso-C15:0 and iso-C15:0; major quinones are MK-9 and MK-10.

Conclusions:

• Strain AGMB00274^T represents a novel species of the genus Parabacteroides.
• The proposed name for the novel species is Parabacteroides faecalis sp. nov.
• The type strain is AGMB00274^T (=KCTC 25286^T = GDMCC 1.2742^T).
• This finding contributes to the taxonomic knowledge of the Parabacteroides genus in swine-associated microbiota.