Description of Paraclostridium bifermentans subsp. muricolitidis subsp. nov., emended description of Paraclostridium bifermentans (Sasi Jyothsna et al., 2016), and creation of Paraclostridium bifermentans subsp. bifermentans subsp. nov

Taxonomic studies of strain PAGU 1678T, an obligately anaerobic, gram‐positive, spore‐forming bacterium isolated from biobreeding rat feces, were performed. This strain has been demonstrated to have the ability to exacerbate pathosis in a mouse model of dextran sulfate sodium‐induced ulcerative colitis. Phylogenetic analysis based on the 16S rRNA gene showed high homology with Paraclostridium bifermentans. To clarify the correct taxonomic position of strain PAGU 1678T, a comparative taxonomic study using P. bifermentans PAGU 2008T (═JCM 1386T) and the closely related bacterial species P. benzoelyticum PAGU 2068T (═LMG 28745T) was carried out. Despite the close similarity of 16S rRNA gene sequences, DNA‐DNA hybridization between strain PAGU 1678T and P. bifermentans PAGU 2008T was 60.03% on average, average nucleotide identity was 96.17%, and it was shown to have different genomic sequences. Biochemically, strain PAGU 1678T could be differentiated from P. bifermentans PAGU 2008T by H2S production. Furthermore, strain PAGU 1678T was characterized by the presence of two phospholipids with different polarity on polar lipid analysis. In addition, strain PAGU 1678T differed from P. bifermentans PAGU 2008T in findings on whole‐cell protein analysis and matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry. On the basis of these biochemical and genetic characteristics, a novel subspecies of P. bifermentans with the name Paraclostridium bifermentans subsp. muricolitidis subsp. nov. is here proposed, with PAGU 1678T (═CCUG 72489T ═NBRC 113386T) as the type strain, which automatically creates P. bifermentans subsp. bifermentans subsp. nov. JCM 1386T (═ATCC 638T ═DSM 14991T).