Description of Hoskinsella mucinilytica gen. nov., sp. nov., a mucin-degrading isolate from human faeces, and reclassification of Amedibacillus hominis Abdugheni et al. 2023 as a later heterotypic synonym of Eubacterium hominis Liu et al. 2022 within

Mucin-degrading bacteria are recognized as potential players in weakening of the colonic mucus barrier and increased susceptibility to pathogens in the human gut due to their use of mucus as a nutrient source, sometimes in the context of a fibre-deficient diet. Using intact porcine gastric mucin glycoprotein as the main nutrient source, we isolated a Gram-positive, non-motile, rod-shaped, obligately anaerobic bacterium (UGRO018_0423^T) from faecal samples of a healthy adult. The strain grows with cells arranged in chains. Based on 16S rRNA gene sequence, the strain UGRO018_0423^T shared the highest similarity (96.94% and 96.75%) with <i>Eubacterium hominis</i> New-5^T and <i>Amedibacillus hominis</i> NSJ-176^T, respectively. Phylogenomic analyses based on 120 concatenated phylogenetically informative protein markers (full-length protein and protein domain sequences) and examination of the placement within the Genome Taxonomy Database (GTDB) reference tree revealed that the strain UGRO018_0423^T is not affiliated with the genera <i>Eubacterium</i> or <i>Amedibacillus sensu stricto</i>, and placed UGRO018_0423^T within the family <i>Erysipelotrichaceae</i>. This also indicated the problematic taxonomic status of both <i>E. hominis</i> and <i>A. hominis</i> that were placed within the same genus as UGRO018_0423^T based on phylogenomic analyses. Genomic comparisons based on average nucleotide identity and digital DNA-DNA hybridization between UGRO018_0423^T and <i>E. hominis</i> New-5^T and <i>A. hominis</i> NSJ-176^T indicated that the strain UGRO018_0423^T represents a novel species. These results combined with further chemotaxonomic and phenotypic characterization indicated that strain UGRO018_0423^T (=DSM 116809^T=ATCC TSD-466^T) represents a novel species within a novel genus in the family <i>Erysipelotrichaceae</i>, for which the name <i>Hoskinsella mucinilytica</i> gen. nov., sp. nov. is proposed. In addition, based on genomic comparisons and phylogenomic analysis, <i>A. hominis</i> is reclassified as a later heterotypic synonym of <i>E. hominis,</i> and both species are transferred into the genus <i>Hoskinsella</i> gen. nov. with reclassification of <i>E. hominis</i> as <i>Hoskinsella hominis</i> comb. nov. and <i>A. hominis</i> as <i>Hoskinsella hominifaecis</i> nom. nov.