Bacteroides humanifaecis sp. nov., isolated from faeces of healthy Korean.

Two obligately anaerobic, Gram-stain-negative, non-motile, non-spore-forming and short rod shaped bacteria, designated KGMB07931 and KGMB10229, were isolated from faeces of two Korean persons. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains KGMB07931 and KGMB10229 were very similar to each other (99.9%) and grouped within the genus Bacteroides, displaying the highest similarity with Bacteroides uniformis ATCC 8492 (97.5%), Bacteroides rodentium JCM 16496 (96.6%), and Bacteroides fluxus YIT 12057 (94.5%). Both strains grew optimally at 37 °C and pH 7.5 in the presence of 0.5% (w/v) NaCl. The complete genome of KGMB07931 comprises 3,335 protein-coding genes with a total of 4,240,638 bp and an average G + C content of 46.3 mol%. The major fatty acids were C cis9, anteiso-C, iso-C, and Summed Feature 11 (iso-C 3OH and/or C DMA); the predominant respiratory quinones were MK-9 and MK-10; the major fermentation end products were acetate and isobutyrate. The genome of strain KGMB07931 encoded the starch utilization system (Sus) operon, susABCDEFG, suggesting that this strain uses many complex polysaccharides that cannot be digested by humans. Based on polyphasic taxonomic data, strains KGMB07931 and KGMB10229 represent a novel species within the genus Bacteroides, for which the name Bacteroides humanifaecis sp. nov. is proposed. The type strain is KGMB07931 (= KCTC 25160 = NBRC 115005).