A novel bacterial strain, MSB163, was isolated from the stool sample of a healthy mother, 4 weeks after giving birth via vaginal delivery. Taxonomic identification tools revealed that MSB163 belongs to the genus Bacteroides, but it is distinct from any currently known species. The closest related species is Bacteroides cellulosilyticus strain BFG- 250, with an average nucleotide identity (fastANI) of 94.51%. The genome length of MSB163 is 6,440,948 bp and the GC content 42.95%. Two plasmids were identified in the whole genome sequence. MSB163 is a Gram-negative, rod-shaped, non-motile anaerobic bacterium. The optimum growth conditions were at 37 °C, pH 7 and 0% (w/v) NaCl. The respiratory quinones were the menaquinones MK- 10 and MK- 11 and C15:0 ANTEISO was the major fatty acid. The predominant polar lipids were phosphatidylethanolamine, diphosphatidylglycerol and phospholipid. According to the taxonomic results and physiological analysis, strain MSB163 represents a novel species of the genus Bacteroides, for which we propose the name Bacteroides maternus, since the type strain was isolated from the stool sample of a mother. B. maternus type strain (MSB163) sequencing can be accessed under the biosample ID SAMN3953129 on NCBI. The strain was deposited on BCCM/LMG Bacteria Collection under the accession number LMG 33,374 and Leibniz Institut DSMZ GMBH under the accession number DSM 117,047.
Keywords: Bacteroides maternus nov; Anaerobic bacteria; Gut microbiome; New species.
© 2025. The Author(s).