Gut microbiota profiles and characterization of cultivable fungal isolates in IBS patients.

Studies so far conducted on irritable bowel syndrome (IBS) have been focused mainly on the role of gut bacterial dysbiosis in modulating the intestinal permeability, inflammation, and motility, with consequences on the quality of life. Limited evidences showed a potential involvement of gut fungal communities. Here, the gut bacterial and fungal microbiota of a cohort of IBS patients have been characterized and compared with that of healthy subjects (HS). The IBS microbial community structure differed significantly compared to HS. In particular, we observed an enrichment of bacterial taxa involved in gut inflammation, such as Enterobacteriaceae, Streptococcus, Fusobacteria, Gemella, and Rothia, as well as depletion of health-promoting bacterial genera, such as Roseburia and Faecalibacterium. Gut microbial profiles in IBS patients differed also in accordance with constipation. Sequence analysis of the gut mycobiota showed enrichment of Saccharomycetes in IBS. Culturomics analysis of fungal isolates from feces showed enrichment of Candida spp. displaying from IBS a clonal expansion and a distinct genotypic profiles and different phenotypical features when compared to HS of Candida albicans isolates. Alongside the well-characterized gut bacterial dysbiosis in IBS, this study shed light on a yet poorly explored fungal component of the intestinal ecosystem, the gut mycobiota. Our results showed a differential fungal community in IBS compared to HS, suggesting potential for new insights on the involvement of the gut mycobiota in IBS. KEY POINTS: • Comparison of gut microbiota and mycobiota between IBS and healthy subjects • Investigation of cultivable fungi in IBS and healthy subjects • Candida albicans isolates result more virulent in IBS subjects compared to healthy subjects.

Alloscardovia theropitheci sp. nov., isolated from the faeces of gelada baboon, the 'bleeding heart' monkey (Theropithecus gelada).

A novel irregularly shaped and slightly curved rod bacterial strain, GLDI4/2T, showing activity of fructose 6-phosphate phosphoketolase was isolated from a faecal sample of an adult gelada baboon (Theropithecus gelada). Phylogenetic analyses based on 16S rRNA genes as well as multilocus sequences (representing fusA, gyrB and xfp genes) and the core genome revealed that GLDI4/2T exhibited phylogenetic relatedness to Alloscardovia omnicolens DSM 21503T and to Alloscardovia macacae DSM 24762T. Comparative analysis of 16S rRNA gene sequences confirmed the phylogenetic results showing the highest gene sequence identity with strain A. omnicolens DSM 21503T (96.0 %). Activities of α- and ß-gluco(galacto)sidases were detected in strain GLDI4/2T, which is characteristic for almost all members of the family Bifidobacteriaceae. Compared to other Alloscardovia species its DNA G+C content (43.8 mol%) was very low. Phylogenetic studies and the evaluation of phenotypic characteristics, including the results of biochemical, physiological and chemotaxonomic analyses, confirmed the novel species status for strain GLDI4/2T, for which the name Alloscardoviatheropitheci sp. nov. is proposed. The type strain is GLDI4/2T (=DSM 106019T=JCM 32430T).

Bifidobacterium jacchi sp. nov., isolated from the faeces of a baby common marmoset (Callithrix jacchus).

A novel Bifidobacterium strain, MRM 9.3T, was isolated from a faecal sample of a baby common marmoset (Callithrixjacchus). Cells were Gram-stain-positive, non-motile, non-sporulating, non-haemolytic, facultatively anaerobic and fructose 6-phosphate phosphoketolase-positive. Phylogenetic analyses based on 16S rRNA genes as well as multilocus sequences (representing hsp60, rpoB, clpC, dnaJ and dnaG genes) and the core genomes revealed that strain MRM 9.3T exhibited phylogenetic relatedness to Bifidobacterium myosotis DSM 100196T. Comparative analysis of 16S rRNA gene sequences confirmed the phylogenetic results showing the highest gene sequence identity with strain B.ifidobacterium myosotis DSM 100196T (95.6 %). The average nucleotide identity, amino acid average identity and in silico DNA-DNA hybridization values between MRM 9.3T and DSM 100196T were 79.9, 72.1 and 28.5 %, respectively. Phenotypic and genotypic features clearly showed that the strain MRM 9.3T represents a novel species, for which the name Bifidobacterium jacchi sp. nov. is proposed. The type strain is MRM 9.3T (=DSM 103362T =JCM 31788T).

Characterization of Bifidobacterium species in feaces of the Egyptian fruit bat: Description of B. vespertilionis sp. nov. and B. rousetti sp. nov.

Fifteen bifidobacterial strains were obtained from faeces of Rousettus aegyptiacus; after grouping them by RAPD PCR only eight were selected and characterized. Analysis of 16S rRNA and of five housekeeping (hsp60, rpoB, clpC, dnaJ, dna G) genes revealed that these eight strains were classified into five clusters: Cluster I (RST 8 and RST 16T), Cluster II (RST 9T and RST 27), Cluster III (RST 7 and RST 11), Cluster IV (RST 19), Cluster V (RST 17) were closest to Bifidobacterium avesanii DSM 100685T (96.3%), Bifidobacterium callitrichos DSM 23973T (99.2% and 99.7%), Bifidobacterium tissieri DSM 100201T (99.7 and 99.2%), Bifidobacterium reuteri DSM 23975 T (98.9%) and Bifidobacterium myosotis DSM 100196T (99.3%), respectively. Strains in Cluster I and strain RST 9 in Cluster II could not be placed within any recognized species while the other ones were identified as known species. The average nucleotide identity values between two novel strains, RST 16T and RST 9T and their closest relatives were lower than 79% and 89%, respectively. In silico DNA-DNA hybridization values for those closest relatives were 32.5 and 42.1%, respectively. Phenotypic and genotypic tests demonstrated that strains in Cluster I and RST 9T in Cluster II represent two novel species for which the names Bifidobacterium vespertilionis sp. nov. (RST 16T=BCRC 81138T=NBRC 113380T=DSM 106025T ; RST 8=BCRC 81135=NBRC 113377) and Bifidobacterium rousetti sp. nov. (RST 9T=BCRC 81136T=NBRC 113378T=DSM 106027T) are proposed.