Search

Background: Primary sclerosing cholangitis (PSC) is a chronic, fibroinflammatory, cholestatic liver disease of unknown etiopathogenesis, often associated with inflammatory bowel diseases. Recent evidence ascribes, together with immunologic and environmental components, a significant role to the intestinal microbiota or its molecules in the PSC pathogenesis., Methods: By metagenomic sequencing of 16S rRNA and ITS2 loci, we describe the fecal microbiota and mycobiota of 26 pediatric patients affected by PSC and concomitant ulcerative colitis (PSC-UC), 27 patients without PSC but with UC (UC), and 26 healthy subjects (CTRLs)., Results: Compared with CTRL, the bacterial and fungal gut dysbiosis was evident for both PSC-UC and UC groups; in particular, Streptococcus, Saccharomyces, Sporobolomyces, Tilletiopsis, and Debaryomyces appeared increased in PSC-UC, whereas Klebsiella, Haemophilus, Enterococcus Collinsella, Piptoporus, Candida, and Hyphodontia in UC. In both patient groups, Akkermansia, Bacteroides, Parabacteroides, Oscillospira, Meyerozyma and Malassezia were decreased. Co-occurrence analysis evidenced the lowest number of nodes and edges for fungi networks compared with bacteria. Finally, we identified a specific patient profile, based on liver function tests, bacterial and fungal signatures, that is able to distinguish PSC-UC from UC patients., Conclusions: We describe the gut microbiota and mycobiota dysbiosis associated to PSC-UC disease. Our results evidenced a gut imbalance, with the reduction of gut commensal microorganisms with stated anti-inflammatory properties (ie, Akkermansia, Bacteroides, Parabacteroides, Oscillospira, Meyerozyma, and Malassezia) and the increase of pathobionts (ie, Streptococcus, Saccharomyces, and Debaryomyces) that could be involved in PSC progression. Altogether, these events may concur in the pathophysiology of PSC in the framework of UC., (© 2023 Crohn’s & Colitis Foundation. Published by Oxford University Press on behalf of Crohn’s & Colitis Foundation.)

Abstract: Latium, a region in central Italy, is known for its extensive volcanic areas that make a significant contribution to the arsenic (As) contamination of freshwater environments, even though some degree of As water pollution may be caused by human activities. The information available on indigenous As-resistant prokaryotes in aquatic environments of Latium is, however, still limited. In this study, we describe new bacteria that are resistant to arsenic toxicity and were isolated from the surface waters of Lake Vico and the Sacco River, two groundwater systems in Latium, as well as from bottled natural mineral water from the same region. The 16S rRNA gene sequence analysis for the As-resistant strains in lake and river waters points to a prevalence of β- and γ-Proteobacteria, while α-Proteobacteria, Firmicutes and Bacteroidetes are represented to a lesser extent. By contrast, solely γ-Proteobacteria were isolated from groundwater samples. The presence of Actinobacteria was documented exclusively in bottled mineral water. In addition, we conducted a DNA sequence-based study on the gene codifying arsB, an As(III) efflux membrane protein pump related to arsenic resistance, for all the As-resistant bacterial isolates. A phylogenetic analysis was carried out on the newly sequenced 16S rRNA genes and arsB in the present study as well as on an additional 16S rRNA/arsB dataset we obtained previously from Lake Albano, from the Tiber and from a well in Bassano Romano located in Latium (Davolos and Pietrangeli, 2011). Overall, the phylogenetic diversity of As-resistant bacteria in underground water was very limited if compared with lentic and lotic waters. Lastly, our molecular data support the hypothesis that the horizontal gene transfer of ars in As-containing freshwater environments is not limited to closely-related genomes, but also occurs between bacteria that are distant from an evolutionary viewpoint, thereby indicating that such genetic events may be considered a source of microbial resistance to arsenic-toxicity. [Copyright &y& Elsevier]

Several aquatic environments are arsenic (As)-contaminated by geochemical sources and by residues derived from industrial and agricultural activities. In the current study, arsenic-resistant bacterial strains were isolated from Lake Albano, the Tiber River and a freshwater well (Bassano Romano), three sites located in the Latium region, central Italy, in which volcanic formations and aquifers containing As contribute to water As contamination. Bacteria capable of either oxidising As(III) or reducing As(V) belonged, on the basis of the 16S rRNA gene sequences, to the Proteobacteria, Firmicutes and Bacteroidetes. Moreover, phylogenetic analysis conducted on the gene codifying the ArsB, an As(III) efflux membrane protein pump related to the arsenic resistance, suggested the occurrence of horizontal arsB transfer events for some of the examined environmental strains, even among taxa belonging to taxonomically distant bacteria. Overall, these results showed that in each of the environments investigated, bacteria related to the redox of As coexisted, confirming important roles of microbial populations in the speciation of As and increasing the knowledge in view of the bioremoving of As compounds. [ABSTRACT FROM AUTHOR]

Background: This cross-sectional study aimed to explore the microbial composition of the gut and its possible association with the Mediterranean diet (MD) after adjusting for demographic and anthropometric characteristics in a sample of healthy young Italian adults., Methods: Gut microbiota, demographic information, and data on adherence to MD and physical activity (PA) habits were collected in a sample of 140 university students (48.6% males, mean age 22.5 ± 2.9) with a mean body mass index (BMI) of 22.4 ± 2.8 kg/m 2 (15.2-33.8) and a mean PA level of 3006.2 ± 2973.6 metabolic equivalent (MET)-minutes/week (148-21,090)., Results: A high prevalence of Firmicutes and Bacteroidetes was found in all the fecal samples. Significant dissimilarities in the microbiota composition were found on the basis of MD adherence and PA levels ( p = 0.001). At the genus level, Streptococcus and Dorea were highly abundant in overweight/obese individuals, Ruminococcus and Oscillospira in participants with lower adherence to MD, and Lachnobacterium in subjects with low levels of PA ( p = 0.001). A significantly higher abundance of Paraprevotella was shown by individuals with lower BMI, lower MD adherence, and lower PA levels ( p = 0.001)., Conclusions: This study contributes to the characterization of the gut microbiome of healthy humans. The findings suggest the role of diet and PA in determining gut microbiota variability.

Human gut microbiota directly influences health and provides an extra means of adaptive potential to different lifestyles. To explore variation in gut microbiota and to understand how these bacteria may have co-evolved with humans, here we investigate the phylogenetic diversity and metabolite production of the gut microbiota from a community of human hunter-gatherers, the Hadza of Tanzania. We show that the Hadza have higher levels of microbial richness and biodiversity than Italian urban controls. Further comparisons with two rural farming African groups illustrate other features unique to Hadza that can be linked to a foraging lifestyle. These include absence of Bifidobacterium and differences in microbial composition between the sexes that probably reflect sexual division of labour. Furthermore, enrichment in Prevotella, Treponema and unclassified Bacteroidetes, as well as a peculiar arrangement of Clostridiales taxa, may enhance the Hadza's ability to digest and extract valuable nutrition from fibrous plant foods.