Selenobaculum gbiensis gen. nov. sp. nov., a new bacterium isolated from the gut microbiota of a patient with Crohn's disease

The human gut microbiota is a complex ecology comprising approximately 10 to 100 trillion microbial cells. Most of the bacteria detected by 16s rRNA sequencing have yet to be cultured, but intensive attempts to isolate the novel bacteria have improved our knowledge of the gut microbiome composition and its roles within human host. In our culturomics study, a novel gram-negative, motile, obligately anaerobic, rod-shaped bacteria, designated as strain ICN-92133(T), was isolated from a fecal sample of a 26-year-old patient with Crohn's disease. Based on the 16s rRNA sequence of strain ICN92133(T), the phylogeny analysis placed the strain into the family Selenomonadaceae, showing 93.91% similarity with the closely related Massilibacillus massiliensis strain DSM 102838(T). Strain ICN-92133(T) exhibited a genome size of 2,679,003 bp with a GC content of 35.5% which was predicted to contain 26 potential virulence factors and five antimicrobial resistance genes. In comparative genomic analysis, strain ICN-92133(T) showed digital DNA-DNA Hybridization and OrthoANI values lower than 21.9% and 71.9% with the closest type strains, respectively. In addition, comparing phenotypic, biochemical, and cellular fatty acids with those of closely related strains revealed the distinctiveness of strain ICN-92133(T). Based on the taxonogenomic results, strain ICN-92133(T) is proposed as a novel species belonging to a new genus. Therefore, we suggest the name of the new genus Selenobaculum gen. nov. within the family Selenomonadaceae and strain ICN-92133(T) (= KCTC 25622(T) = JCM 36070(T)) as a type strain of new species Selenobaculum gbiensis sp. nov.