Description of Gracilibacillus phocaeensis sp. nov., a new halophilic bacterium isolated from Senegalian human stool.

Using the taxonogenomics method, we describe Gracilibacillus phocaeensis strain Marseille-P3801, a new species previously isolated from a salty stool of a 20-year-old man from N'Diop, Senegal. It is a Gram-positive, aerobic and motile bacillus. The major fatty acids are C15:0-anteiso (59%), C16:0 (16%) and C17:0-anteiso (11%). Strain Marseille-P3801 exhibits a 98.45% sequence similarity with Gracilibacillus thailandensis strain TP2-8, the phylogenetically closest species. Its genome is 4.66 Mb with 39.6 mol% G + C content.

Taxonogenomics description of Bacillus dakarensis sp. nov., Bacillus sinesaloumensis sp. nov. and Bacillus massiliogabonensis sp. nov., three new species isolated from human stools.

Using microbial culturomics, three Bacillus strains were isolated, identified and characterized following the taxonogenomics strategy. Bacillus dakarensis strain Marseille-P3515T (=CSURP3515), Bacillus sinesaloumensis strain Marseille-P3516T (=CSURP3516), and Bacillus massiliogabonensis strain Marseille-P2639T (=CSURP2639) were isolated from human stool samples. The phylogenetic analysis, phenotypic characteristics and genotypic data presented here prove that these three bacteria are different from previously known bacterial species with standing in nomenclature and represent new Bacillus species.

Salt in stools is associated with obesity, gut halophilic microbiota and Akkermansia muciniphila depletion in humans.

BACKGROUND/OBJECTIVES: High salt intake has been linked to several diseases including obesity and an increased risk of death; however, fecal salinity and the ability of salt to alter the gut microbiota, which was recently identified as an instrumental factor for health and disease, remains poorly explored. METHODS/SUBJECTS: We analyzed the fecal samples of 1326 human individuals for salinity by refractometry, 572 for gut microbiota by culturomics, and 164 by 16S rRNA-targeted metagenomics. Geographical origin, age, gender, and obesity were tested as predictors of fecal salinity and halophilic diversity. All halophilic isolates were characterized by taxonogenomics and their genome sequenced. RESULTS: Fecal salinity was associated with obesity independently of geographical origin, gender, and age. The first 2 human-associated halophilic archaeal members were isolated along with 64 distinct halophilic species, including 21 new species and 41 known in the environment but not in humans. No halophiles grow in less than 1.5% salinity. Above this threshold, the richness of the halophilic microbiota was correlated with fecal salinity (r = 0.58, p < 0.0001). 16S metagenomics linked high fecal salinity to decreased diversity (linear regression, p < .035) and a depletion in anti-obesity Akkermansia muciniphila and Bifidobacterium, specifically B. longum and B. adolescentis. Genomics analysis suggested that halophilic microbes are not only transient passengers but may be residents of the human gut. CONCLUSIONS: High salt levels are associated with alteration of the gut microbial ecosystem and halophilic microbiota, as discovered during this study. Further studies should clarify if the gut microbiota alterations associated with high salt levels and the human halophilic microbiota could be causally related to human disease, such as obesity.

'Gracilibacillus phocaeensis' sp. nov., 'Sediminibacillus massiliensis' sp. nov. and 'Virgibacillus ndiopensis' sp. nov., three halophilic species isolated from salty human stools by culturomics.

We report the isolation of three bacterial strains that could not be identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry screening. 'Gracilibacillus phocaeensis' sp. nov., 'Sediminibacillus massiliensis' sp. nov. and 'Virgibacillus ndiopensis' sp. nov. are halophilic species isolated from salty human stools by culturomics.

Description of 'Bacillus dakarensis' sp. nov., 'Bacillus sinesaloumensis' sp. nov., 'Gracilibacillus timonensis' sp. nov., 'Halobacillus massiliensis' sp. nov., 'Lentibacillus massiliensis' sp. nov., 'Oceanobacillus senegalensis' sp. nov., 'Oceanobacillus timonensis' sp. nov., 'Virgibacillus dakarensis' sp. nov. and 'Virgibacillus marseillensis' sp. nov., nine halophilic new species isolated from human stool.

We report the main characteristics of 'Bacillus dakarensis' P3515T sp. nov., 'Bacillus sinesaloumensis' P3516T sp. nov., 'Gracilibacillus timonensis' P2481T sp. nov., 'Halobacillus massiliensis' P3554T sp. nov., 'Lentibacillus massiliensis' P3089T sp. nov., 'Oceanobacillus senegalensis' P3587T sp. nov., 'Oceanobacillus timonensis' P3532T sp. nov., 'Virgibacillus dakarensis' P3469T sp. nov. and 'Virgibacillus marseillensis' P3610T sp. nov., that were isolated in 2016 from salty stool samples (≥1.7% NaCl) from healthy Senegalese living at Dielmo and N'diop, two villages in Senegal.