Copranaerobaculum intestinale gen. nov., sp. nov., a novel anaerobic bacterium isolated from human faeces.

A novel obligate anaerobic organism, designated DONG20-135T, was isolated from human faeces collected in Beijing, PR China. Cells were Gram-stain-negative, rod-shaped, non-motile and non-spore-forming. Growth occurred at 25‒45 °C (optimum, 30‒35 °C), a pH range of 6-9 (optimum, pH 8) and in the presence of 0‒3.5 % (w/v) NaCl (optimum, 0.5‒1.5 %). The major fatty acids were C16 : 0, C18 : 1 ω9c and C10 : 0, the polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, four glycolipids, six aminolipids, three aminophospholipids and four unidentified lipids. No respiratory quinones were detected. The cell-wall peptidoglycan of the strain was A1γ type, containing meso-diaminopimelic acid. The 16S rRNA gene sequences shared a lower identity (<92.7 % similarity) with the described species. The phylogenetic tree based on 16S rRNA gene sequences and the protein-concatamer tree showed that strain DONG20-135T formed a distinct lineage within the family Erysipelotrichaceae. The genomic DNA G + C content was 42.2 mol%. Based on the results of phenotypic, chemotaxonomic and genomic analyses, strain DONG20-135T represents a novel genus of the family Erysipelotrichaceae, for which the name Copranaerobaculum intestinale gen. nov., sp. nov. is proposed (=KCTC 15868T=CGMCC 1.17357T).

Short-term high-dose gavage of hydroxychloroquine changes gut microbiota but not the intestinal integrity and immunological responses in mice.

AIMS: Hydroxychloroquine (HCQ), a widely used antimalarial drug, is proposed to treat coronavirus disease 2019 (COVID-19). However, no report is currently available regarding the direct effects of HCQ on gut microbiota, which is associated with the outcomes of elderly patients with COVID-19. Here, we first investigated the effects of HCQ on intestinal microecology in mice. MAIN METHODS: Fifteen female C57BL/6J mice were randomly divided into two groups: HCQ group (n = 10) and control group (n = 5). Mice in the HCQ group were administered with HCQ at dose of 100 mg/kg by gavage daily for 14 days. The feces of mice were collected before and on the 7th and 14th days after HCQ challenge, and then analyzed by 16S rRNA amplicon sequencing. At the end of the experiment, the hematology, serum biochemistry and cytokines were determined, respectively. The mRNA expression of tight junction proteins in colonic tissues were also studied by RT-PCR. KEY FINDINGS: HCQ challenge had no effects on the counts of white blood cells, the levels of serum cytokines, and the gene expression of tight junction proteins in colon. HCQ also did not increase the content of serum d-lactate in mice. Notably, HCQ significantly decreased the diversity of gut microbiota, increased the relative abundance of phylum Bacteroidetes whereas decreased that of Firmicutes. SIGNIFICANCE: Short-term high dose HCQ challenge changes gut microbiota but not the intestinal integrity and immunological responses in mice. Special attention should be paid to the effects of HCQ on intestinal microecology in future clinical use.