Highlights d The depletion of Roseburia is associated with alcohol consumption in human cohorts d R. intestinalis ameliorates the experimental ALD in mice regardless of viability d Flagellin from R. intestinalis protects on ethanol-disrupted gut barrier functions d The ethanol-induced gut microbiota dysbiosis is restored by R. intestinalis

Administration of probiotics has been linked to immune regulation and changes in gut microbiota composition, with effects on atopic dermatitis (AD). In this study, we investigated amelioration of the symptoms of AD using Lactobacillus paracasei KBL382 isolated from the feces of healthy Koreans. Mice with Dermatophagoides farinae extract (DFE)-induced AD were fed 1 × 10 9 CFU d −1 of L. paracasei KBL382 for 4 weeks. Oral administration of L. paracasei KBL382 significantly reduced AD-associated skin lesions, epidermal thickening, serum levels of immunoglobulin E, and immune cell infiltration. L. paracasei KBL382-treated mice showed decreased production of T helper (Th)1-, Th2-, and Th17-type cytokines, including thymic stromal lymphopoietin, thymus, and activation-regulated chemokine, and macrophage-derived chemokine, and increased production of the anti-inflammatory cytokine IL-10 and transforming growth factor-β in skin tissue. Intake of L. paracasei KBL382 also increased the proportion of CD4+ CD25+ Foxp3+ regulatory T cells in mesenteric lymph nodes. In addition, administration of L. paracasei KBL382 dramatically changed the composition of gut microbiota in AD mice. Administration of KBL382 significantly ameliorates AD-like symptoms by regulating the immune response and altering the composition of gut microbiota.

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An obligately anaerobic, Gram-stain-positive and spore-forming strain, SNUG30386T was isolated from a faecal sample of a healthy Korean subject. The strain formed a round ivory-coloured colony and cells were chained rods with tapered ends, approximately 2.0–2.5×0.6–0.8 μm in size. The taxonomic analysis indicated that strain SNUG30386T was within the family Lachnospiraceae . According to the 16S rRNA gene sequence similarity, the closest species to strain SNUG30386T was Clostridium symbiosum (95.6 %), followed by Enterocloster asparagiformis (94.8 %), Enterocloster clostridioformis (94.8 %) and Enterocloster lavalensis (94.6 %). The evolutionary tree based on 16S rRNA gene sequences demonstrated that strain SNUG30386T had split apart at a unique branch point far from other close relatives. Its DNA G+C content was 48.3 mol% calculated from the whole genome sequence. The major cellular fatty acids were C16 : 0 and C14 : 0. Compared to those of the closely related species, strain SNUG30386T showed distinct biochemical activities such as being unable to utilize most of carbon sources except d-glucose and l-arabinose. As a result, based on its unique phylogenetic clade and taxonomic characteristics, we conclude that strain SNUG30386T represents a novel species within the genus Clostridium , for which the name Clostridium fessum sp. nov. is proposed. The type strain of the novel species is SNUG30386T (=KCTC 15633T= JCM 32258T).