Hominibacterium faecale gen. nov., sp. nov., an anaerobic L-arginine-degrading bacterium isolated from human feces

Two anaerobic, mesophilic bacteria SF3(T) and ASD5510 were isolated from human feces in two different countries. Strain SF3(T) shared 99.9% of 16S rRNA gene sequence similarity with strain ASD5510, and 92.8% similarity with the most similar strain Aminipila butyrica DSM 103574(T). Strain SF3(T) was an anaerobic, Gram-stain-positive bacterium. Cells of strain SF3(T) were short rods with 0.3-0.4 mu m in width x 2.0-2.4 mu m in length and occurred mostly in pairs or short chains. Spore formation was not observed. The strain grew optimally at 35 ? (range from 20 to 45 ?), pH 7.5 (pH 6.0-8.5) and without NaCl addition (range from 0 to 20 g l(-1) NaCl). Yeast extract was an essential growth factor for strain SF3(T), L-arginine and gamma-aminobutyrate were utilized as substrates for growth. The major cellular fatty acids were iso-C-15:0 and C-16:0 DMA. The main polar lipids were aminophospholipid (APL), diphosphatidylglycerol (DPG) and phosphatidylethanolamine (PE). The G + C content of the genomic DNA of the strain SF3(T) was 47.38 mol %. The paired genomic average amino acid identity (AAI) and percentage of conserved proteins (POCP) values showed relatedness of less than 61.0 and 39.4% with type strains of order Eubacteriales. On the basis of phenotypic, phylogenetic and phylogenomic evidence strain SF3(T) constitutes a novel species in a novel genus, for which the name Hominibacterium faecale gen. nov., sp. nov. is proposed. The type strain is SF3(T) (= CCAM 730(T) = JCM 34755(T) = KCTC 25324(T)).

Automated summary

Two anaerobic, mesophilic bacteria SF3(T) and ASD5510 were isolated from human feces in different countries. Strain SF3(T) showed high sequence similarity with strain ASD5510 and a similar strain Aminipila butyrica DSM 103574(T) based on 16S rRNA gene analysis. Strain SF3(T) exhibited a Gram-stain-positive morphology and grew optimally under specific conditions. Based on phenotypic, phylogenetic, and phylogenomic evidence, strain SF3(T) represents a novel species in a novel genus named Hominibacterium faecale gen. nov., sp. nov.