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 T and KGMB10229, were isolated from faeces of two Korean persons. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains KGMB07931 T 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 T (97.5%), Bacteroides rodentium JCM 16496 T (96.6%), and Bacteroides fluxus YIT 12057 T (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 T 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 18:1  cis9, anteiso-C 15:0 , iso-C 15:0 , and Summed Feature 11 (iso-C 17:0 3OH and/or C 18:2 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 T 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 T 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 T (= KCTC 25160 T  = NBRC 115005 T ).