Search Results (66)

Metabolic dysfunction-associated steatohepatitis (MASH) is a complex, multifactorial disease heavily influenced by the gut–liver axis. While enterotoxigenic Bacteroides fragilis (ETBF) and its principal virulence factor, B. fragilis toxin (BFT)—a zinc-dependent metalloprotease—are well-known for disrupting intestinal barriers, their potential systemic impact on distant organs remains an emerging area of interest. Although various gut-derived factors contribute to hepatic inflammation, the precise molecular triggers that exacerbate the transition from simple steatosis to progressive fibrosis remain incompletely understood. This review proposes the “Direct Structural Disruption” hypothesis, examining the biological activity of BFT and its proposed role in MASH pathogenesis. We postulate that under permissive conditions, systemic BFT may target hepatic structural proteins (e.g., cadherins). This hypothesized architectural impairment amplifies canonical fibrogenic signaling and hepatic stellate cell (HSC) activation. In addition, we discuss current challenges in the detection and characterization of systemic BFT, particularly the technical limitations in clinical diagnostics stemming from its profound structural homology with host metalloproteinases. Future research integrating advanced diagnostic methodologies and liver-specific in vivo models is essential to elucidate these pathophysiological mechanisms and evaluate the ETBF-BFT axis as a complementary target in progressive MASH. Full article

Bacteroides fragilis is a major commensal bacterium of the human colon. However, enterotoxigenic B. fragilis (ETBF) secretes B. fragilis toxin (BFT), a zinc-dependent metalloprotease that cleaves E-cadherin and promotes chronic inflammation and colorectal tumorigenesis. Despite extensive research, the cellular receptor for BFT remains unidentified. In this study, we developed His-tagged recombinant BFT variants including both catalytically active and inactive forms to facilitate biochemical and functional analyses. Functional assays confirmed that the active variant retained proteolytic activity and induced characteristic cellular responses, while the inactive variant served as an effective negative control. These results establish a robust experimental platform for BFT receptor identification and mechanistic studies of BFT-host interactions. The active and inactive BFT variants provide essential molecular tools for investigating ETBF pathogenicity and developing therapeutic interventions. Full article

Lipopolysaccharides (LPSs) are potent pro-inflammatory neurotoxins abundant in the gut microbiome and originate primarily from Gram-negative bacteria, such as Escherichia coli. LPS levels increase with brain aging and accumulate around neurons in Alzheimer’s disease (AD) brains. Microbiome-generated LPS and other endotoxins cross gut barriers, enter systemic circulation, and translocate across the blood–brain barrier into vascularized brain regions. These processes are exacerbated by aging and neurovascular diseases. Although pro-homeostatic systems mitigate LPS effects, these defenses can fail. This study provides the first evidence that acyloxyacyl hydrolase (AOAH; EC 3.1.1.77), a microglia-enriched LPS detoxifying enzyme, shows reduced expression in AD brain tissue. Analysis of AD patient brains revealed reduced AOAH messenger RNA (mRNA) levels, accompanied by elevated expression of microRNA (hsa-miR-450b-5p), an inflammation regulator. Furthermore, luciferase reporter assays demonstrated that miR-450b-5p specifically targets the AOAH 3′-UTR, leading to a dose-dependent suppression of reporter activity. Also, in vitro experiments on human neuronal glial (HNG) cells further confirmed down-regulation of AOAH expression at protein levels by miR-450b-5p. These findings suggest miR-450b-5p-mediated AOAH deficiency drives LPS-associated neurotoxicity and inflammatory neurodegeneration in AD. Full article

The MALDI-TOF MS Bruker Biotyper MBT subtyping IVD module enables the early detection of cfiA-positive Bacteroides fragilis (cfiA+ BF) during bacterial identification. However, the relationship between genetic positivity, phenotypic resistance, and clinical outcomes has not been fully elucidated. This retrospective study analyzed B. fragilis isolates from three Hong Kong hospitals between 2021 and 2025 to examine their prevalence and the clinical utility of MALDI-TOF MS in rapid cfiA detection. Antibiotic susceptibility testing, cfiA gene detection using MALDI-TOF MS, and Oxford Nanopore sequencing were performed. Medical records were reviewed, and univariate analyses and multivariate logistic regression were used to identify factors associated with cfiA positivity and 30-day all-cause mortality. Overall, B. fragilis exhibited a high rate of antibiotic resistance. Concomitant resistance to carbapenems and metronidazole was identified in three isolates. Among the 166 isolates, 40 (24.1%) were cfiA-positive. cfiA detection by MALDI-TOF MS showed 100% concordance with the gene sequencing results and correlated strongly with phenotypic carbapenem resistance (Φ = 0.82, p < 0.001 for meropenem; Φ = 0.70, p < 0.001 for ertapenem; Φ = 0.63, p < 0.001 for imipenem). Phylogenetic analysis revealed two distinct clusters corresponding to cfiA status, each exhibiting genetic diversity based on multi-locus sequence typing (MLST). The cfiA+ BF isolates demonstrated high-level phenotypic carbapenem resistance in the presence of upstream insertion sequences. The predominant sequence type (ST) among cfiA+ BF isolates was ST157, and 70% of ST157 isolates harbored IS1187 in the upstream region of cfiA. Gene sequencing also identified other emerging beta-lactamase genes bla_OXA-347 and bla_MUN. The 30-day all-cause mortality following B. fragilis infection was 13.3%, with independent predictors including a high Charlson Comorbidity Index (OR = 1.30; p = 0.02) and the absence of early source control (OR = 4.84; p = 0.03). This study highlights the widespread occurrence of cfiA+ BF in Hong Kong and the clinical significance of rapid cfiA detection. Continuous surveillance is essential to monitor the ongoing threat of antibiotic resistance in B. fragilis. Full article

Background: The COVID-19 pandemic accelerated the development of diverse vaccine platforms, including mRNA, adenoviral vector, and protein subunit vaccines. Given the growing evidence that the gut microbiome modulates vaccine-induced immunity, this study compared the effects of a protein subunit vaccine (NVX-CoV2373), an mRNA vaccine (BNT162b2), and an adenoviral vector vaccine (ChAdOx1) on gut microbiome diversity following booster vaccination. Methods: We conducted a prospective cohort study involving 35 healthy adults who received an NVX-CoV2373 booster. Stool and blood samples were collected before vaccination and three weeks afterward. Gut microbiome profiles were analyzed using 16S rRNA gene sequencing, and the results were compared with our previous cohorts who received BNT162b2 or ChAdOx1 vaccines. Results: The NVX-CoV2373 booster was associated with a significant increase in the Shannon diversity index (p = 0.027), indicating enhanced alpha diversity. This finding contrasts with the decrease or absence of significant short-term change observed following repeated administrations of adenoviral vector and mRNA vaccines, respectively. Notably, NVX-CoV2373 vaccination was accompanied by an increased relative abundance of beneficial taxa such as Bacteroides fragilis and a decrease in Prevotella bivia. In comparison, repeated ChAdOx1 doses resulted in a sustained reduction in alpha diversity, whereas BNT162b2 showed a transient post-booster rise followed by a long-term decline in species richness. Conclusions: In the booster setting, the protein subunit vaccine NVX-CoV2373 exerted a distinct and favorable effect on gut microbiome diversity, increasing alpha diversity in contrast to the patterns observed with mRNA and adenoviral vector booster vaccines. Full article

This research was conducted to evaluate the safety and effects of two probiotic candidate strains, Enterococcus faecium (E. faecium) and B. fragilis (BF), which were isolated from healthy sheep, on various factors such as intestinal structure, growth performance, organ indices, and gut microbiota in female C57BL/6J mice. A total of fifty mice were categorized into five groups: BF108, BF109, EF108, EF109, and a control group. The results indicated that mice in the EF108 and BF109 groups experienced a significant increase in body weight by day 28 compared to the control group (p < 0.05). Additionally, the liver index in the BF108 and EF108 groups was significantly lower (p < 0.05) than that of the control group. The length of the colon was also significantly greater (p < 0.05) in the EF109 and BF109 groups relative to the control group. According to the linear discriminant analysis effect size (LEfSe), the presence of probiotics led to an increased relative abundance of Pediococcus acidilactici in the EF109 and BF109 groups, while Lactiplantibacillus plantarum was the most prevalent strain in the EF108 and BF108 groups. Finally, Spearman correlation analysis demonstrated a positive association between Bacillota and Bacteroidota as well as Verrucomicrobiota. Additionally, Bacteroidota displayed positive relationships with Verrucomicrobiota and Planctomycetota, while showing a negative correlation with Actinomycetota and Gemmatimonadota, supporting its potential use as next-generation probiotics. In summary, our results indicate probiotics may have a role in promoting intestinal health by enhancing intestinal shape and histological characteristics. Full article

Background/Objectives: Bacteroides species are key members of the human gut microbiota but can act as opportunistic pathogens. This study investigated the genomic features of clinical Bacteroides isolates from southern Thailand. Methods: Sixteen isolates were collected from body fluids, tissues, and pus at Songklanagarind Hospital (2022–2024). Whole-genome sequencing was performed on the BGI platform, followed by genome assembly, annotation, average nucleotide identity (ANI), pairwise single-nucleotide polymorphism (SNP) analysis, antimicrobial resistance (AMR) gene profiling, plasmid prediction, virulence screening, and phylogenetic analysis. Results: ANI and SNP analysis revealed two clusters: one comprising B. ovatus, B. intestinigallinarum, and B. thetaiotaomicron, and another mainly B. fragilis with one B. hominis isolate. All isolates were resistant to ampicillin, cephalothin, and penicillin; six B. fragilis strains were resistant to all tested antibiotics. The β-lactamase gene cepA was detected in all B. fragilis isolates, and plasmids were predicted in two genomes. Three virulence types (capsule formation, lipopolysaccharide modification, and stress response) were identified. Phylogenomic analysis confirmed species-level assignments and revealed underrecognized lineages, emphasizing the value of genome-based approaches for accurate classification. Conclusions: Clinical Bacteroides isolates display diverse resistance and virulence profiles, highlighting the importance of strain-level genomic surveillance. Full article

Obesity, a global health crisis, is linked to chronic low-grade inflammation and an increased risk of developing various chronic diseases, including psoriasis. Probiotics, postbiotics, and fermented foods have shown promise in combating inflammation and obesity. This study aimed to develop and characterize a chicory extract fermented with Bacteroides fragilis (C-B. fragilis) and its supernatant (phyto-postbiotic supernatant, PPS) as potential treatments for obesity, inflammation, and psoriasis. Polyphenols, organic acids, and amino acids were identified in the metabolic profile of C-B. fragilis. PPS and C-B. fragilis extract both revealed potent anti-inflammatory, anti-obesity, and antioxidant activities. In vitro assays highlighted that PPS significantly reduced the production of reactive oxygen species (ROS), the expression of pro-inflammatory cytokines (TNF-α, IL-6, IL-8) in macrophages, and the secretion of IL-1β in LPS-stimulated PBMCs. Moreover, PPS decreased triglyceride content in human adipocytes and modulated the expression of leptin and adiponectin. Regarding psoriasis, PPS reduced pro-inflammatory cytokines (IL-6, IL-1β) in both psoriatic keratinocytes and a co-culture model mimicking the skin-adipose tissue interface. In addition, PPS lowered S100 calcium-binding protein A7 (S100A7) expression in the co-culture model, suggesting a potential role in restoring skin barrier function. In summary, our results highlight the potential of PPS extract (supernatant of chicory fermentation by Bacteroides fragilis) as a promising therapeutic strategy for the management of obesity-related inflammation and psoriasis. Full article

Bacteroides fragilis is a usually beneficial colonizer of the human gut that can also act as an opportunistic pathogen, causing infection and contributing to the development and progression of important diseases. The production and secretion of the B. fragilis toxin (BFT), the main virulence factor of this bacterium, distinguishes enterotoxigenic (ETBF) from non-toxigenic (NTBF) strains. Although NTBF does not produce the BFT, certain strains can exhibit unexpected pathogenic characteristics. The complex interactions between B. fragilis and the other intestinal bacteria, such as Clostridioides difficile, the leading cause of antibiotic-associated diarrhea in healthcare settings, highlights its ambivalent role of benefactor and pathogen. In fact, although B. fragilis plays a part in preventing colonization and infection due to C. difficile (CDI), both these anaerobic bacteria can contribute to the development and progression of colorectal cancer (CRC), one of the most prevalent malignant tumors of the digestive tract. This review provides an overview of the dual nature of B. fragilis, focusing on the peculiarities of ETBF and NTBF, delving into B. fragilis interaction with C. difficile and impacts on the host. Full article

Bacteroides fragilis, a prominent commensal of the human gut microbiota, plays a vital role in immune system regulation through its capsular polysaccharide A (PSA), which requires a glycolipid anchor structurally reminiscent of lipid A. While canonical Escherichia coli lipid A acts as a potent TLR4 agonist contributing to septic shock and inflammatory disorders, certain B. fragilis-derived glycolipids demonstrate antagonistic effects, offering potential as anti-inflammatory agents. In this study, we report the synthesis and preliminary computational evaluation of a library of glycolipids inspired by B. fragilis lipid A. Three lipid As, including a tetra-acylated 1-phosphoryl lipid A analog (Tetra C-1), were synthesized and assessed using molecular docking simulations targeting the human TLR4/MD-2 complex. Docking results reveal that Tetra C-1 exhibits more favorable antagonist binding characteristics compared to the well-studied TLR4 antagonist Eritoran. This work highlights a microbiota-informed strategy for the development of novel TLR4 antagonists, potentially enabling targeted modulation of innate immunity for therapeutic applications in inflammatory diseases and as vaccine adjuvants. Full article

Colorectal cancer (CRC) remains a major global challenge, with growing attention to its pathogenesis as mediated by the gut microbiome and epigenetic regulation. Despite therapeutic progress, clinical management remains difficult. CRC accounts for ~10% of cancers and is the second leading cause of cancer death worldwide. Romania bears a substantial burden, with many diagnoses at advanced stages. Etiology—Integrated Genetic, Environmental, and Microbial Determinants. Hereditary syndromes explain 10–15% of cases; most are sporadic, with hypermutated MSI/POLE (~15%), non-hypermutated chromosomal instability (~85%), and a CpG island methylator phenotype (~20%). GWAS implicate loci near SMAD7, TCF7L2, and CDH1; in Romania, SMAD7 rs4939827 associates with risk. Lifestyle exposures—high red/processed meat, low fiber, adiposity, alcohol, and smoking—shape susceptibility. Microbiome–Epigenome Interactions. Dysbiosis promotes carcinogenesis via genotoxins (e.g., colibactin), hydrogen sulfide, activation of NF-κB/STAT3, barrier disruption, and epigenetic remodeling of DNA methylation and microRNAs. Fusobacterium nucleatum, enterotoxigenic Bacteroides fragilis, and pks⁺ Escherichia coli exemplifies these links. Population-Specific Risk—Romania within Lifestyle–Microbiome Evidence. Incidence is rising, including early-onset disease. Romania lacks CRC-specific microbiome datasets. However, metabolic cohorts show loss of butyrate producers, enrichment of pathobionts, and SCFA imbalance—patterns that mirror European CRC cohorts—and exhibit regional heterogeneity. Beyond Fusobacterium nucleatum. Additional oncobacteria shape tumor biology. Peptostreptococcus stomatis activates integrin α6/β4→ERBB2–MAPK and can bypass targeted inhibitors, while Parvimonas micra enhances WNT/β-catenin programs and Th17-skewed immunity. Together, these data support a systems view in which microbial cues and host epigenetic control jointly drive CRC initiation, progression, metastasis, and treatment response. Full article

Background: Enterotoxigenic Bacteroides fragilis (ETBF) carries the bft toxin gene, which influences the host immune response and inflammatory pathways and promotes colorectal cancer (CRC). This study investigated the potential role of ETBF in CRC liver metastasis. Methods: We reviewed the records of 226 consecutive patients who underwent curative-intent (R0) resection of CRC liver metastases. ETBF DNA in fresh-frozen metastasis specimens was quantified using droplet digital PCR (ddPCR). Patients were grouped into very-low (≤80%; N = 178), low (80–90%; N = 24), and high (>90%; N = 24) ETBF-DNA groups. Three tissue cores per specimen were stained for CD8, CD4, CD20, FOXP3, CD68, and CD163, and immune-cell densities were measured digitally (cells/mm²). Results: ETBF DNA was detected in 219 of 226 lesions (96.9%). The densities of cytotoxic CD8⁺ T-cells, effector CD4⁺ T-cells, CD20⁺ B-cells, and CD163⁺ macrophages did not differ significantly by ETBF-DNA group (P_trend all > 0.12). FOXP3⁺ regulatory T-cells (Tregs) decreased (P_trend = 0.010), and CD68⁺ macrophages increased (P_trend = 0.020) as ETBF-DNA levels increased. ETBF-DNA levels in CRC liver metastases were not associated with disease-free survival or overall survival or serum C-reactive protein levels. Conclusions: ETBF was present in almost all CRC liver metastases. Higher ETBF levels were associated with a tumor-immune microenvironment enriched in CD68⁺ macrophages and deficient in FOXP3⁺ Tregs, suggesting that ETBF facilitates immune evasion without loss of effector lymphocytes. Although ETBF-DNA levels did not predict survival in this single-center cohort, the potential role of ETBF in immune remodeling and as a candidate biomarker and therapeutic target in metastatic CRC warrants further study. Full article

Enterotoxigenic Bacteroides fragilis (ETBF) promotes colitis-associated cancer through the Bacteroides fragilis toxin (BFT), which induces colonic inflammation that can be exacerbated by external stimuli. We found that BALB/c mice infected with ETBF and treated with azoxymethane and dextran sodium sulfate (DSS) developed numerous distal colon polyps more rapidly than B6 mice, suggesting strain differences in ETBF-induced tumorigenicity. Using a bft gene-deficient ETBF strain, we confirmed BFT’s crucial role in ETBF-promoted tumorigenesis and inflammation. While both 1% and 2% DSS induced comparable polyp formation, 1% DSS minimized mortality, proving sufficient for maximizing polyp development. Mechanistically, BFT-mediated tumorigenesis involves NF-κB/CXCL1 signaling in colonic epithelial cells exposed to BFT and DSS, a pathway known to be critical for inflammation and cancer progression. This model provides a valuable platform for dissecting ETBF’s colitis-associated cancer-promoting mechanisms, particularly those involving BFT, and for evaluating BFT-targeted therapeutic interventions. Full article

Background/Objectives: Effective drug delivery systems require precise formulation and understanding of excipient impact on active pharmaceutical ingredient (API) stability and efficacy, as uncontrolled interactions can compromise outcomes. This study developed and validated a semi-solid extrusion (SSE) 3D printing method for polyvinyl alcohol (PVA)-based hydrogel disks with metronidazole (MET). These disks served as a standardized platform to assess excipient influence on MET’s antimicrobial activity, focusing on plasticizers (polyethylene glycol 400, glycerol, propylene glycol, and diethylene glycol monoethyl ether)—excipients that modify hydrogel properties for their application in printing dressing matrices—with the platform’s capabilities demonstrated using in vitro antimicrobial susceptibility testing against Bacteroides fragilis. Methods: Hydrogel inks based on PVA with added plasticizers and MET were prepared. These inks were used to 3D-print standardized disks. The MET content in the disks was precisely determined. The antimicrobial activity of all formulation variants was evaluated using the disk diffusion method against B. fragilis. Results: The incorporated plasticizers did not negatively affect the antimicrobial efficacy of MET against B. fragilis. All printed hydrogel matrices exhibited clear antimicrobial activity. The 3D-printed disks showed high repeatability and precision regarding MET content. Conclusions: SSE 3D printing is viable for manufacturing precise, reproducible MET-loaded PVA hydrogel disks. It provides a standardized platform to evaluate diverse excipient impacts, like plasticizers, on API antimicrobial performance. The tested plasticizers were compatible with MET. This platform aids rational formulation design and screening for optimal excipients in designed formulations and for various pharmaceutical applications. Full article

Introduction: Functional gastrointestinal disorders (FGIDs) are common comorbidities that affect the life quality of children with autism. Objective: This study investigated the link between clinical history and specific colonic fecal microbiota (CFM) markers with the pathophysiology of FGIDs in young children with autism patients. Methods: Thirty-nine young patients (2 and 18 years) were included in the study of FGIDs (+) cases (n = 18) and FGIDs (-) (n = 21) controls. Gastrointestinal disorders were diagnosed by standardized clinical tools (ROMA-IV and six-item gastrointestinal severity index), while bacterial markers, including Bacteroidetes, Firmicutes, Actinomycetes (Phyla); Lactobacillales, Clostridiales, Bifidobacteriales (Orders); B. fragilis, F. prausnitzii, B. longum, D. vulgaris and A. muciniphila (Species), were detected by targeting 16S rRNA and two-step PCR protocol. Results: The overall prevalence of FGIDs was significantly (p < 0.05) associated with cesarean delivery, the duration of milk formula consumption, and the presence of early intestinal symptoms during infancy. Furthermore, Bacteroidetes, Lactobacillales, B. longum, D. vulgaris, and A. muciniphila concentrations were significantly (p ≤ 0.03) higher in stool of patients with moderate symptoms, compared to those who were asymptomatic. Conclusions: Our results suggest that the CFM composition is a potential physiological predictor of FGID pathophysiology in a severity-dependent way in children with autism. Full article