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Enterococcus faecium (Efm) is a versatile pathogen, responsible for multidrug-resistant infections, especially in hospitalized immunocompromised patients. Its population structure has been characterized by diverse clades (A1, A2, and B (reclassified as E. lactis (Ela)), adapted to different environments, and distinguished by their resistomes and virulomes. These features only partially explain the predominance of clade A1 strains in nosocomial infections. We investigated in vitro interaction of 50 clinical isolates (clade A1 Efm) against 75 commensal faecal isolates from healthy humans (25 clade A2 Efm and 50 Ela). Only 36% of the commensal isolates inhibited clinical isolates, while 76% of the clinical isolates inhibited commensal isolates. The most apparent overall differences in inhibition patterns were presented between clades. The inhibitory activity was mainly mediated by secreted, proteinaceous, heat-stable compounds, likely indicating an involvement of bacteriocins. A custom-made database targeting 76 Bacillota bacteriocins was used to reveal bacteriocins in the genomes. Our systematic screening of the interactions between nosocomial and commensal Efm and Ela on a large scale suggests that, in a clinical setting, nosocomial strains not only have an advantage over commensal strains due to their possession of AMR genes, virulence factors, and resilience but also inhibit the growth of commensal strains. [ABSTRACT FROM AUTHOR]

Previous work indicated that the incidence of travellers' diarrhoea (TD) is higher in soldiers of British origin, when compared to soldiers of Nepalese descent (Gurkhas). We hypothesise that the composition of the gut microbiota may be a contributing factor in the risk of developing TD in soldiers of British origin. This study aimed to characterise the gut microbial composition of Gurkha and non-Gurkha soldiers of the British Army. Recruitment of 38 soldiers (n = 22 Gurkhas, n = 16 non-Gurkhas) and subsequent stool collection, enabled shotgun metagenomic sequencing-based analysis of the gut microbiota. The microbiota of Gurkhas had significantly (P < 0.05) lower diversity, for both Shannon and Simpson diversity indices, using species level markers than the gut microbiota of non-Gurkha soldiers. Non-metric Multidimensional Scaling (NMDS) of the Bray-Curtis distance matrix revealed a significant difference in the composition of the gut microbiota between Gurkhas and non-Gurkha soldiers, at both the species level (P = 0.0178) and the genus level (P = 0.0483). We found three genera and eight species that were significantly enriched in the non-Gurkha group and one genus (Haemophilus) and one species (Haemophilus parainfluenzae) which were enriched in the Gurkha group. The difference in the microbiota composition between Gurkha soldiers and soldiers of British origin may contribute to higher colonization resistance against diarrhoeal pathogens in the former group. Our findings may enable further studies into interventions that modulate the gut microbiota of soldiers to prevent TD during deployment. [ABSTRACT FROM AUTHOR]

Background: We conducted a single-arm interventional study, to explore mucosal changes associated with clinical remission under oral vancomycin (OV) treatment, in primary sclerosing cholangitis-associated inflammatory bowel disease (PSC-IBD); NCT05376228., Methods: Fifteen patients with PSC and active colitis (median fecal calprotectin 459 µg/g; median total Mayo score 5) were treated with OV (125 mg QID) for 4 weeks and followed-up for a further 4 weeks of treatment withdrawal (8 weeks, end-of-study). Colonic biopsies were obtained at baseline and Week 4. Clinical assessments, and serum and stool samples (metagenomics, metatranscriptomics, and metabolomics) were collected at Weeks 0, 2, 4, and 8. The primary efficacy outcome measure was the induction of clinical remission., Results: Oral vancomycin resulted in clinical remission in 12/15 patients and significant reductions in fecal calprotectin. Oral vancomycin was associated with reduced abundances of Lachnospiraceae, genera Blautia and Bacteroides; and enrichment of Enterobacteriaceae, and genera Veillonella, Akkermansia, and Escherichia. Oral vancomycin treatment was associated with the downregulation of multiple metatranscriptomic pathways (including short-chain fatty acid [SCFA] metabolism and bile acid [BA] biotransformation), along with host genes and multiple pathways involved in inflammatory responses and antimicrobial defence; and an upregulation of genes associated with extracellular matrix repair. Oral vancomycin use resulted in the loss of specific fecal SCFAs and secondary BAs, including lithocholic acid derivatives. Colitis activity relapsed following OV withdrawal, with host mucosal and microbial changes trending toward baseline., Conclusions: Four weeks of OV induces remission in PSC-IBD activity, associated with a reduction in gut bacterial diversity and compositional changes relating to BA and SCFA homeostasis., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation.)

Introduction: Primary sclerosing cholangitis (PSC) is the classical hepatobiliary manifestation of inflammatory bowel disease (IBD). The strong association between gut and liver inflammation has driven several pathogenic hypotheses to which the intestinal microbiome is proposed to contribute. Pilot studies of faecal microbiota transplantation (FMT) in PSC and IBD are demonstrated to be safe and associated with increased gut bacterial diversity. However, the longevity of such changes and the impact on markers of disease activity and disease progression have not been studied. The aim of this clinical trial is to determine the effects of repeated FMT as a treatment for PSC-IBD., Methods and Analysis: FAecal micRobiota transplantation in primary sclerosinG chOlangitis (FARGO) is a phase IIa randomised placebo-controlled trial to assess the efficacy and safety of repeated colonic administration of FMT in patients with non-cirrhotic PSC-IBD. Fifty-eight patients will be recruited from six sites across England and randomised in a 1:1 ratio between active FMT or FMT placebo arms. FMT will be manufactured by the University of Birmingham Microbiome Treatment Centre, using stool collected from rigorously screened healthy donors. A total of 8 weekly treatments will be delivered; the first through colonoscopic administration (week 1) and the remaining seven via once-weekly enema (up to week 8). Participants will then be followed on a 12-weekly basis until week 48 from the first treatment visit. The primary efficacy outcome will be to determine the effect of FMT on serum alkaline phosphatase values over time (end of study at 48 weeks). Key secondary outcomes will be to evaluate the impact of FMT on other liver biochemical parameters, PSC risk scores, circulating and imaging markers of liver fibrosis, health-related quality of life measures, IBD activity and the incidence of PSC-related clinical events. Key translational objectives will be to identify mucosal metagenomic, metatranscriptomic, metabolomic and immunological pathways associated with the administration of FMT., Ethics and Dissemination: The protocol was approved by the South Central-Hampshire B Research Ethics Committee (REC 23/SC/0147). Participants will be required to provide written informed consent. The results of this trial will be disseminated through national and international presentations and peer-reviewed publications., Trial Registration Number: The trial was registered at ClinicalTrials.gov on 23 February 2024 (NCT06286709). Weblink: Study Details | FAecal Microbiota Transplantation in primaRy sclerosinG chOlangitis | ClinicalTrials.gov., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.)

The intestinal epithelium serves as a physical and functional barrier against harmful substances, preventing their entry into the circulation and subsequent induction of a systemic immune response. Gut barrier dysfunction has recently emerged as a feature of ageing linked to declining health, and increased intestinal membrane permeability has been shown to promote heightened systemic inflammation in aged hosts. Concurrent with age-related changes in the gut microbiome, the thymic microenvironment undergoes a series of morphological, phenotypical and architectural alterations with age, including disorganisation of the corticomedullary junction, increased fibrosis, increased thymic adiposity and the accumulation of senescent cells. However, a direct link between gut barrier dysbiosis and thymic involution leading to features of immune ageing has not been explored thus far. Herein, we reveal strong associations between enhanced microbial translocation and the peripheral accumulation of terminally differentiated, senescent and exhausted T cells and the compensatory expansion of regulatory T cells in older adults. Crucially, we demonstrate that aged germ-free mice are protected from age-related increases in intestinal permeability, highlighting the direct impact of mucosal permeability on thymic ageing. Together, these findings establish a novel mechanism by which gut barrier dysfunction drives systemic activation of the immune system during ageing through thymic involution. This enhances our understanding of drivers of T cell ageing and opens up the possibility for the use of microbiome-based interventions to restore immune homeostasis and promote healthy ageing in older adults., (© 2024 The Author(s). Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)