The role of the gut microbiota in patients with Kleefstra syndrome

Kleefstra Syndrome (KS) is a rare monogenetic syndrome, caused by haploinsufficiency of the euchromatic histone methyl transferase 1 (EHMT1) gene, an important regulator of neurodevelopment. The clinical features of KS include intellectual disability, autistic behavior and gastrointestinal problems. The gut microbiota, an important modifier of the gut-brain-axis, may constitute an unexplored mechanism underlying clinical KS variation. We investigated the gut microbiota composition of 23 individuals with KS (patients) and 40 of their family members, to test whether (1) variation in the gut microbiota associates with KS diagnosis and (2) variation within the gut microbiota relates with KS syndrome symptoms. Both alpha and beta diversity of patients were different from their family members. Genus Coprococcus 3 was lower in abundance in patients compared to family members. Moreover, abundance of genus Merdibacter was lower in patients versus family members, but only in participants reporting intestinal complaints. Within the patient group, behavioral problems explained 7% of beta diversity variance. Also, within this group, we detected higher levels of Atopobiaceae – uncultured and Ruminococcaceae Subdoligranulum associated with higher symptom severity. These significant signatures in the gut microbiota composition in patients with KS suggest that microbiota differences are part of the KS phenotype.     

Exploring the bacterial gut microbiota of supralittoral talitrid amphipods

Talitrid amphipods (sandhoppers and beach fleas) are typical of the supralittoral zone. They are known to thrive on stranded materials, including detrital marine angiosperms and macroalgae, as well as occasional dead animals. In this work, the gut microbiota of five species of talitrid amphipods (Talitrus saltator, Talorchestia ugolinii, Sardorchestia pelecaniformis, Orchestia montagui and Orchestia stephenseni) collected in Sardinia (Italy) has been investigated through: i) metabarcoding analysis of the amplified 16S rRNA V4 region; and ii) quantification of family 48 glycosyl hydrolase genes (GHF48), involved in cellulose degradation. Results indicate that, though talitrid gut biodiversity is not directly related to taxon or sampling locality, the animals' digestive tracts may host species-specific bacterial communities. In particular, gut microbiota of O. montagui, an inhabitant of Posidonia banquettes and macro-algae mat, showed the greatest differences in taxonomic composition and the highest proportion of GHF48 genes with respect to 16S rRNA genes. These results suggest that the different talitrid species may host species-specific bacterial communities whose function could partially reflect the different microhabitats and food preferences of their host.     

Comparison of the gut microbiota of short-term and long-term medical workers and non-medical controls: a cross-sectional analysis

ObjectivesThe hospital environment has been implicated in the enrichment and exchange of pathogens and antibiotic resistance, but its potential in shaping the symbiotic microbial community of hospital staff is unclear. This study was designed to evaluate the alteration of the gut microbiome in medical workers compared to non-medical controls.MethodsA prospective cross-sectional cohort study was conducted in the intensive care unit (ICU) and other departments of a centre in north-eastern China. Faecal samples of 175 healthy medical workers—short-term (1–3 months) workers (n = 80) and long-term (>1 year) workers (n = 95)—and 80 healthy non-medical controls were analysed using 16S rRNA amplicon sequencing. The hospital environmental samples (n = 9) were also analysed.ResultsThe gut microbiomes of medical workers exhibited marked deviations in diversity and alteration in microbial composition and function. Short-term workers showed significantly higher abundances of taxa such as Lactobacillus, Butyrivibrio, Clostridiaceae, Clostridium, Ruminococcus, Dialister, Bifidobacterium, Odoribacter, and Desulfovibrio and lower abundances of Bacteroides and Blautia than the controls. Long-term workers showed higher abundances of taxa such as Dialister, Veillonella, Clostridiaceae, Clostridium, Bilophila, Desulfovibrio, Pseudomonas, and Akkermansia and lower abundances of Bacteroides and Coprococcus than the controls. The medical workers' department (ICU versus non-ICU) and position (resident doctor versus nursing staff) also impacted their gut microbiome. Compared with the non-ICU workers, workers in the ICU showed a significant increase in the abundances of Dialister, Enterobacteriaceae, Phascolarctobacterium, Pseudomonas, Veillonella, and Streptococcus and a marked depletion of Faecalibacterium, Blautia, and Coprococcus. In contrast with the nursing staff, the resident doctors showed a significant increase in Erysipelotrichaceae and Clostridium and a decrease in Bacteroides, Blautia, and Ruminococcus in the gut microbiome. Moreover, we found that the microbiota of hospital environments potentially correlated with the workers' gut microbiota.ConclusionsOur findings demonstrated structural changes in the gut microbial community of medical workers.     

16S rRNA gene sequencing analysis of gut microbiome in a mini-pig diabetes model

Background : Currently, increasing attention is being paid to the important role of in-testinal microbiome in diabetes. However, few studies have evaluated the characteris-tics of gut microbiome in diabetic miniature pigs, despite it being a good model animal for assessing diabetes. Methods : In this study, a mini- pig diabetes model (DM) was established by 9- month high- fat diet (HFD) combined with low- dose streptozotocin, while the animals fed standard chow diet constituted the control group. 16S ribosomal RNA (rRNA) gene sequencing was performed to assess the characteristics of the intestinal microbiome in diabetic mini- pigs. Results : The results showed that microbial structure in diabetic mini- pigs was altered, reflected by increases in levels of Coprococcus_3 and Clostridium_sensu_stricto_1 , which were positively correlated with diabetes, and decreases in levels of the bac-teria Rikenellaceae , Clostridiales_vadinBB60_group , and Bacteroidales_RF16_group , which were inversely correlated with blood glucose and insulin resistance. Moreover, PICRUSt- predicted pathways related to the glycolysis and Entner- Doudoroff super-pathway, enterobactin biosynthesis, and the L - tryptophan biosynthesis were signifi-cantly elevated in the DM group. Conclusion : These results reveal the composition and predictive functions of the in-testinal microbiome in the mini- pig diabetes model, further verifying the relationship between HFD, gut microbiome, and diabetes, and providing novel insights into the application of the mini- pig diabetes model in gut microbiome research.     

Analysis of the periodontal microbiota in childhood-type hypophosphatasia

Seven patients with childhood-type hypophosphatasia and healthy control subjects were analysed for microbiological and clinical evidence of periodontitis. The bacterial composition of the subgingival plaque was analysed by 16S rRNA gene cloning and sequencing, DNA-DNA hybridisation with specific probes, and specific PCR. With the exception of the genus Veillonella and the species Eikenella corrodens, no differences between the cohorts in the composition of bacterial orders, families, genera, and species were observed. Accordingly, patients showed only slightly more bleeding on probing (BOP), and slightly higher periodontal probing depth (PPD) values than controls. Although this pilot study did not have the power to assess the prevalence of periodontitis in HP, we suggest that most paediatric patients suffering from HP harbour a subgingival microbiota, which is comparable to that of the healthy population.     

Tracking bacterial DNA patterns in septic progression using 16s rRNA gene amplicon sequencing analysis

Bloodstream infections remain prevalent in intensive care units, leading to a public health challenge worldwide. Routine diagnosis is mainly based on blood culture, but the technique is limited by its time-consuming process and relatively low sensitivity. Emerging molecular diagnostic tools, such as 16S metagenomics, have been developed for detecting bacteria in the blood samples of septic patients. Using a collection of 168 blood samples from 96 septic patients, 16S metagenomics method followed by bioinformatics were applied to study bacterial alterations during the pathogenesis of sepsis. Significant taxonomic variations were found between the two survival groups at different therapeutic time points through sequential 16S metagenomics research. The results on the third day during the treatment course were notably distinct among the studied groups. 16S metagenomics approach can bring novel genetic insight about microbiological fluctuations during septic progression, which may be utilized as a complementary prognostic application. Further etiologic and pathophysiologic explorations are needed to fully explain the linkage between clinical outcomes and genetic changes.     

Maternal gut bacteria drive intestinal inflammation in offspring with neurodevelopmental disorders by altering the chromatin landscape of CD4+ T cells

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The gut microbiota perspective for interventions in MS

The heritable genetic variation that explains phenotypic differences in a population fluctuates for different autoimmune disorders. Particularly in multiple sclerosis (MS) etiology, modest genetic and major environmental effects emerge.Increasingly recognized as a major environmentally shaped contributor to disease and treatment outcomes are gut microbiota.As discussed here, the observed impact of gut microbiome on MS pathophysiology, involves both quantitative and functional changes in composition, metabolism, gut permeability, homeostasis and modulation of the immune system. Although the first supplementary therapeutic interventions have been approached in general autoimmune disorders they are relatively cruder and a translation of knowledge from other pathologies is valuable but still required.Consequently initial therapeutic interventions with microbiota for autoimmune disorders could be correspondingly improved.