Search Results (207)

The oral–gut microbiota axis is a relatively new field of research. Although most studies have focused separately on the oral and gut microbiota, emerging evidence has highlighted that the two microbiota are interconnected and may influence each other through various mechanisms shaping systemic health. The aim of this review is therefore to provide an overview of the interactions between oral and gut microbiota, and the influence of diet and related metabolites on this axis. Pathogenic oral bacteria, such as Porphyromonas gingivalis and Fusobacterium nucleatum, can migrate to the gut through the enteral route, particularly in individuals with weakened gastrointestinal defenses or conditions like gastroesophageal reflux disease, contributing to disorders like inflammatory bowel disease and colorectal cancer. Bile acids, altered by gut microbes, also play a significant role in modulating these microbiota interactions and inflammatory responses. Oral bacteria can also spread via the bloodstream, promoting systemic inflammation and worsening some conditions like cardiovascular disease. Translocation of microorganisms can also take place from the gut to the oral cavity through fecal–oral transmission, especially within poor sanitary conditions. Some metabolites including short-chain fatty acids, trimethylamine N-oxide, indole and its derivatives, bile acids, and lipopolysaccharides produced by both oral and gut microbes seem to play central roles in mediating oral–gut interactions. The complex interplay between oral and gut microbiota underscores their crucial role in maintaining systemic health and highlights the potential consequences of dysbiosis at both the oral and gastrointestinal level. Some dietary patterns and nutritional compounds including probiotics and prebiotics seem to exert beneficial effects both on oral and gut microbiota eubiosis. A better understanding of these microbial interactions could therefore pave the way for the prevention and management of systemic conditions, improving overall health outcomes. Full article

Background/Objectives: Hepatic cancers, including hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), are major global health concerns due to rising incidence and limited therapeutic success. While traditional risk factors include chronic liver disease and environmental exposures, recent evidence underscores the significance of genetic alterations and gut microbiota in liver cancer development and progression. This review aims to integrate emerging knowledge on the interplay between host genomic changes and gut microbial dynamics in the pathogenesis and treatment of hepatic cancers. Methods: We conducted a comprehensive review of current literature on genetic and epigenetic drivers of HCC and CCA, focusing on commonly mutated genes such as TP53, CTNNB1, TERT, IDH1/2, and FGFR2. In parallel, we evaluated studies addressing the gut–liver axis, including the roles of dysbiosis, microbial metabolites, and immune modulation. Key clinical and preclinical findings were synthesized to explore how host–microbe interactions influence tumorigenesis and therapeutic response. Results: HCC and CCA exhibit distinct but overlapping genomic landscapes marked by recurrent mutations and epigenetic reprogramming. Alterations in the gut microbiota contribute to hepatic inflammation, genomic instability, and immune evasion, potentially enhancing oncogenic signaling pathways. Furthermore, microbiota composition appears to affect responses to immune checkpoint inhibitors. Emerging therapeutic strategies such as probiotics, fecal microbiota transplantation, and precision oncology based on mutational profiling demonstrate potential for personalized interventions. Conclusions: The integration of host genomics with microbial ecology provides a promising paradigm for advancing diagnostics and therapies in liver cancer. Targeting the gut–liver axis may complement genome-informed strategies to improve outcomes for patients with HCC and CCA. Full article

Schizophrenia is a complex psychiatric disorder traditionally linked to neurotransmitter dysregulation, particularly within dopamine and glutamate pathways. However, recent evidence implicates the gut–brain axis as a potential contributor to its pathophysiology. This perspective article proposes a systems-level understanding of schizophrenia that incorporates the role of gut microbial dysbiosis specifically, reductions in short-chain fatty acid (SCFA)-producing taxa, and elevations in pro-inflammatory microbes. These imbalances may compromise gut barrier integrity, stimulate systemic inflammation, and disrupt neurochemical signaling in the brain. We synthesize findings from animal models, clinical cohorts, and microbial intervention trials, highlighting mechanisms such as SCFA regulation, altered tryptophan–kynurenine metabolism, and microbial impacts on neurotransmitters. We also explore microbiome-targeted interventions like probiotics, prebiotics, dietary strategies, and fecal microbiota transplantation (FMT) and their potential as adjunctive therapies. While challenges remain in causality and translation, integrating gut–brain axis insights may support more personalized and biologically informed models of schizophrenia care. Full article

Colorectal cancer (CRC) is a multifactorial disease increasingly recognized for its complex interplay with the gut microbiota. The disruption of microbial homeostasis—dysbiosis—has profound implications for intestinal barrier integrity and host immune function. Pathogenic bacterial species such as Fusobacterium nucleatum, Escherichia coli harboring polyketide synthase (pks) island, and enterotoxigenic Bacteroides fragilis are implicated in CRC through mechanisms involving mucosal inflammation, epithelial barrier disruption, and immune evasion. These pathogens promote pro-tumorigenic inflammation, enhance DNA damage, and suppress effective anti-tumor immunity. Conversely, commensal and probiotic bacteria, notably Lactobacillus and Bifidobacterium species, exert protective effects by preserving epithelial barrier function and priming host immune responses. These beneficial microbes can promote the maturation of dendritic cells, stimulate CD8⁺ T cell cytotoxicity, and modulate regulatory T cell populations, thereby enhancing anti-tumor immunity. The dichotomous role of the microbiota underscores its potential as both a biomarker and a therapeutic target in CRC. Recent advances in studies have explored microbiota-modulating strategies—ranging from dietary interventions and prebiotics to fecal microbiota transplantation (FMT) and microbial consortia—as adjuncts to conventional therapies. Moreover, the composition of the gut microbiome has been shown to influence the responses to immunotherapy and chemotherapy, raising the possibility of microbiome-informed precision oncology therapy. This review synthesizes the current findings on the pathogenic and protective roles of bacteria in CRC and evaluates the translational potential of microbiome-based interventions in shaping future therapeutic paradigms. Full article

Colorectal cancer (CRC) is one of the most prevalent and lethal oncological diseases worldwide, with a concerning rise in incidence, particularly in developing countries. Recent advances in genetic sequencing have revealed that the gut microbiome plays a crucial role in CRC development. Mechanisms such as chronic inflammation, metabolic alterations, and oncogenic pathways have demonstrated that dysbiosis, a disruption of the gut microbiome, is linked to CRC. Associations have been found between tumor progression, treatment resistance, and pathogenic microbes such as Fusobacterium nucleatum and Escherichia coli. A promising approach for CRC prevention and treatment is microbiome manipulation through interventions such as probiotics, prebiotics, fecal microbiota transplantation, and selective antibiotics. This article explores how gut microbiome alterations influence CRC pathogenesis and examines microbiome modulation strategies currently used as adjuncts to traditional treatments. Advances in artificial intelligence, single-cell and spatial transcriptomics, and large-scale initiatives such as the ONCOBIOME Project are paving the way for the identification of microbiome-derived biomarkers for early CRC detection and personalized treatment. Despite promising progress, challenges such as interindividual variability, causal inference, and regulatory hurdles must be addressed. Future integration of microbiome analysis into multi-omics frameworks holds great potential to revolutionize precision oncology in CRC management. Full article

Microscopic colitis (MC) is an idiopathic inflammatory bowel disease characterized by watery, non-bloody diarrhea and histopathological changes but normal endoscopic findings. Increasing evidence now suggests that alterations in the gut microbiota contribute to the pathogenesis of MC. In this narrative review, we summarize evidence from nine case-control studies examining microbial composition using sequencing technology. The research presented here illustrates reduced alpha diversity, high dysbiosis, and pro-inflammatory oral-associated taxa enrichment, such as Veillonella dispar, and loss of protective microbes such as Akkermansia muciniphila and Bacteroides stercoris. These microbial changes have the potential to be non-invasive diagnostic biomarkers that can differentiate MC from other etiologies. In addition, the characterization of gut microbiota in MC can guide personalized therapeutic strategies, such as directed probiotic therapy or fecal microbiota transplantation, to help restore microbial balance. These microbial patterns can be applied to guide the creation of diagnostic biomarkers and personalized therapy. Despite differences in sample types and sequencing methods, general microbial trends highlight the need for further longitudinal and standardized investigations. Full article

Male infertility is an under-recognized global health burden. Accumulating evidence position the intestinal microbiota as a pivotal regulator of testicular function, underpinning the emerging gut microbiota–testis axis. This narrative review introduces the conceptual term “androbactome”, referring to gut microorganisms and microbial genes that are hypothesized to influence androgen biosynthesis, spermatogenesis, and broader reproductive endocrinology. The documented worldwide decline in sperm concentration heightens the urgency of clarifying microbe-mediated influences on male reproductive capacity. The synthesis of preclinical and clinical findings reveals four principal pathways by which dysbiosis compromises fertility: systemic inflammation, oxidative stress, endocrine disruption, and epigenetic alteration. Lipopolysaccharide-driven cytokinaemia, reactive oxygen species generation, hypothalamic–pituitary–gonadal axis suppression, and aberrant germ cell methylation collectively impair sperm quality and hormonal balance. Short-chain fatty acids, secondary bile acids, and indole derivatives emerge as pivotal messengers within this crosstalk. Therapeutic approaches targeting the androbactome, namely dietary optimization, probiotic or prebiotic supplementation, and fecal microbiota transplantation, have demonstrated encouraging improvements in sperm parameters and testosterone levels, yet the causal inference is constrained by predominantly cross-sectional designs and limited long-term safety data. Recognizing the androbactome as a modifiable determinant of male fertility may open new avenues for personalized diagnosis, risk stratification, and adjunctive therapy in regard to idiopathic infertility. The integration of multi-omics platforms to characterize microbial and metabolomic signatures promises to enrich diagnostic algorithms and guide precision interventions, but rigorously controlled longitudinal and interventional studies are required to secure a translational impact. Full article

Gastric cancer (GC) remains a major global health burden, with high morbidity and mortality rates, particularly in regions with prevalent Helicobacter pylori (H. pylori) infection. While H. pylori has long been recognized as a primary carcinogenic agent, recent research has underscored the broader contribution of the gastric microbiota to gastric carcinogenesis. Alterations in the microbial community, or dysbiosis, contribute to chronic inflammation, immune modulation, and epithelial transformation through a range of mechanisms, including disruption of mucosal integrity, activation of oncogenic signaling pathways (e.g., PI3K/Akt, NF-κB, STAT3), and epigenetic alterations. Furthermore, microbial metabolites, such as short-chain fatty acids, secondary bile acids, and lactate, play dual roles in either promoting or suppressing tumorigenesis. Oral and gut-derived microbes, translocated to the gastric niche, have been implicated in reshaping the gastric microenvironment and exacerbating disease progression. The composition of the microbiota also influences responses to cancer immunotherapy, suggesting that microbial profiles can serve as both prognostic biomarkers and therapeutic targets. Emerging strategies, such as probiotics, dietary interventions, and fecal microbiota transplantation (FMT), offer new avenues for restoring microbial balance and enhancing therapy response. This review synthesizes current knowledge on the complex interplay between microbiota and gastric cancer development and emphasizes the potential of microbiome modulation in both preventive and therapeutic frameworks. Full article

The bilateral interaction between the brain and the gut has recently been on the spectrum of researchers’ interests, including complex neural, endocrinological, and immunological signaling pathways. The first case reports and clinical studies have already reported that delivering microbes through fecal microbial transplantation (FMT) may alleviate symptoms of psychiatric disorders. Therefore, modifying the gut microbiota through FMT holds promise as a potential treatment for psychiatric diseases. This scoping review assessed studies from PubMed related to FMT in autism spectrum disorder and attention deficit hyperactivity disorder. The evaluation included nine clinical studies and case reports. The beneficial and persistent effect on the autism spectrum disorder (ASD) symptoms has been reported. Also, an increased microflora diversity and altered levels of neurometabolites in serum were identified, albeit with a tendency to return to baseline over time. The microbiome–gut–brain axis could provide new targets for preventing and treating psychiatric disorders. However, a recent large randomized clinical trial has shed light on the previously collected data and suggested a possible contribution of the placebo effect. This highlights the necessity of large randomized double-blind studies to reliably assess the effect of FMT in ASD. Full article

Background and Objectives: Dysbiosis of the oral–gut axis is related to several extraintestinal inflammatory diseases, including endometriosis. This study aims to assess the microbial landscape and pathogenic potential of distinct biological niches during endometriosis. Materials and Methods: A microbiome meta-analysis was conducted on 182 metagenomic sequences (79 of fecal and 103 of vaginal origin) from women with and without endometriosis. Fecal and vaginal microbial diversity, differential abundance, and functional analysis based on disease status were assessed. Random forest, gradient boosting, and generalized linear modeling were used to predict endometriosis based on differentially enriched bacteria. Results: Only intestinal microbes displayed distinctive taxonomic and functional characteristics in women with endometriosis compared to control women. Taxonomic differences were quantified using the microbial endometriosis index (MEI), which effectively distinguished between individuals with and without the disease. The observed functional enrichment pointed to proinflammatory pathways previously related to endometriosis development. Conclusions: Dysbiosis in the oral–gut microbial community appears to play a prevalent role in endometriosis. Our findings pave the ground for future studies exploring the potential mechanistic involvement of the oral–gut axis in disease pathogenesis. Full article

Prebiotics are food ingredients that result in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefits upon host health. Xylooligosaccharides (XOS) are prebiotic fibers made from xylan. Commercial XOS are mixtures of oligosaccharides containing β-1,4–linked xylose residues. Though they are widely added to foods at different doses, the molecular mechanisms of the catabolism and growth promotion of XOS in the innate gut microbes Lactobacillus spp. remain unknown. In this study, we evaluated the growth-promoting effect using a human fecal isolate, Lactiplantibacillus plantarum strain B20 (Lb. plantarum B20). Assays of bacterial growth and lactic acid production showed stronger growth promotion of XOS than other oligosaccharides did, in a dose- and fraction-dependent pattern. Using the Lb. plantarum strain SK151 genome as a reference, bioinformatic analysis failed to identify any previously characterized genes responsible for the uptake and catabolism of XOS. However, transcriptomic analysis of Lb. plantarum B20 yielded numerous differentially expressed genes (DEGs) during fermentation of XOS. Among these, an oligopeptide ABC transporter (RS03575-03595, composed of five proteins) and a hydrolase (RS06170) were significantly upregulated. Molecular docking analysis indicated that the substrate-binding protein RS03575 may mediate the import of XOS into the cell. Enzymatic assays further demonstrated that RS06170 possesses β-xylosidase activity and can effectively degrade XOS. In addition, functional enrichment analysis suggested that the growth-promoting effect of XOS may be attributed to the upregulation of genes involved in cellular component biogenesis and cell division, potentially through modulation of ribosome function and carbohydrate metabolism in Lb. plantarum B20. These results provide valuable insights into the mechanisms by which XOS promote growth and highlight potential targets for enhancing prebiotic–probiotic interactions. Full article

This pilot study investigated the effects of a reduced sulfur (RS) diet on the gut microbiome composition and fecal metabolome in individuals with remitted or active ulcerative colitis (UC). Thirteen participants maintained their habitual diet (control), while nine followed an RS diet for eight weeks (Wk8). Stool and plasma samples were collected at the baseline and Wk8. The sulfur intake decreased in the RS group (−28 g/1000 kcal) versus the control group (−1.7 g/1000 kcal; p < 0.001). The RS group exhibited a significant decrease in lipopolysaccharide-binding protein (−5280 ng/mL), while these levels increased in the control group (620 ng/mL; p < 0.05). The microbiome analysis showed an increased alpha diversity at Wk8 (p < 0.01), suggesting a microbial shift with a RS intake. The metabolic alterations indicated enhanced nitrogen disposal (increased uric acid, methyluric acid, N-acetyl-L-glutamate) and a higher energy demand (elevated ubiquinol and glucose-pyruvate). The RS diet increased beneficial microbes Collinsella stercoris, Asaccharobacter celatus, and Alistipes finegoldii, while decreasing pathobionts Eggerthella lenta and Romboutsia ilealis. Methyluric acid correlated positively with C. stercoris (β = 0.70) and negatively with E. lenta (β = −0.77) suggesting these microbes utilized this metabolite and influenced the microbiome composition. In conclusion, a RS diet promoted microbial diversity, metabolic adaptations, and reduced inflammation, highlighting its potential as a novel strategy for UC management. Full article

The weaning period is a critical phase for nursery pigs that is characterized by rapid growth and alterations in the intestinal microbiome associated with nutrient utilization. The present study aimed to investigate the efficacy of halquinol, when used as an antibiotic (ABO), on the growth performance, diarrhea incidence, coefficient of apparent total tract digestibility (CATTD), fecal volatile fatty acids (VFAs), and microbiota in pigs. A total of 210 healthy weaned pigs with an average initial weight of 6.9 kg and aged 28 ± 2 days were assigned to five treatments (six pens/treatment) in a complete randomized design, including a control group (T1, CON; feed with no ABO), a colistin group (T2, CLT; feed containing 120 ppm colistin), and three halquinol groups (T3 to T5, HAL; feed containing 180, 240, and 360 ppm halquinol, respectively). The experiment period lasted for 10 days. Field recordings, observation, and feces collection were performed on D1, D5, and D10. CATTD and VFA assessments were conducted on D10. The composition of the fecal microbiota was analyzed via 16S rRNA gene sequencing using the Illumina Miseq platform. The results demonstrated that the in-feed ABO groups exhibited a significantly lower ADFI (p < 0.01). Pigs fed the T3 and T4 diets had the lowest FCR (p < 0.01) on D5 and D10 and, thus, had reduced ADFI (p < 0.01). A quadratic contrast was found in ADFI and FCR on D5 and D10, indicating a negative correlation with HAL concentration (p < 0.01). Pigs fed CLT and HAL had significantly reduced levels of coliform (p < 0.01) and E. coli (p < 0.01). Moreover, pigs receiving ABO also had a lower fecal score compared to those on the CON diet (p < 0.01). Dietary in-feed ABO had no effect on all the parameters of the CATTD on D10 (p > 0.05), except for fat digestibility in pigs that received T4 (p < 0.01). Pigs fed the T4 and T5 diets had higher propionate concentrations and lower A/P ratios than pigs fed T1, T2, and T3 (p < 0.01). The microbial diversity shifted quickly through the early weaning period. The relative abundance of beneficial Enterococcus microbes increased in pigs fed in-feed ABO, whereas the relative prevalence of pathogenic bacteria, such as Escherichia and Klebsiella, decreased. Escherichia and Bacteroides were negatively correlated with carbohydrate digestibility and butyric and valeric acid production (p < 0.05). Overall, the appropriate HAL dosage was 240 ppm (T4), and this antimicrobial can potentially be characterized as an in-feed colistin replacer that improves feed efficiency and fat digestion, enhancing VFA production, alleviating post-weaning diarrhea, and protecting ABO-resistant piglets. Full article

Background: Early gut microbiome development is critical for neonatal health, and its dysbiosis may impact long-term animal productivity. This study examined the effects of parenteral Ceftiofur Crystalline Free Acid (CCFA) on the composition and diversity of the neonatal lamb fecal microbiome. The emergence of antimicrobial resistance genes associated with CCFA exposure was also investigated. Results: There were distinct microbial populations in the CCFA-treated lambs compared to the control group at each time point, with a highly significant decrease in alpha and beta diversity. The CCFA treatment showed a reduction in several key microbial taxa during nursing, but these differences were diminished by day 56. Unlike the control group, CCFA-treated lambs had core microbes potentially carrying multiple antibiotic resistance genes, including those for beta-lactam, fosfomycin, methicillin, and multidrug resistance. Methods: Twenty-four healthy neonatal lambs were randomly assigned to CCFA-treated (n = 12) and control (n = 12) groups. Fecal samples were collected on days 0, 7, 14, 28, and 56. Genomic DNA was extracted and sequenced using the Illumina MiSeq platform. Microbial composition was analyzed using the MG-RAST pipeline with the RefSeq database. Conclusions: Despite temporary reductions in critical bacterial populations during nursing, the early sheep fecal microbiome demonstrated resilience by repopulating after CCFA antibiotic disruption. While this highlights microbiota stability after short-course antibiotic exposure, the transient disturbance underscores potential risks to early gut health. Importantly, persistent CCFA resistance poses environmental dissemination risks, emphasizing the need for cautious antibiotic use in livestock to mitigate ecological impacts. Full article

The gut microbiome, a complex community of microorganisms residing in the intestinal tract, plays a dual role in colorectal cancer (CRC) development, acting both as a contributing risk factor and as a protective element. This review explores the mechanisms by which gut microbiota contribute to CRC, emphasizing inflammation, oxidative stress, immune evasion, and the production of genotoxins and microbial metabolites. Fusobacterium nucleatum, Escherichia coli (pks+), and Bacteroides fragilis promote tumorigenesis by inducing chronic inflammation, generating reactive oxygen species, and producing virulence factors that damage host DNA. These microorganisms can also evade the antitumor immune response by suppressing cytotoxic T cell activity and increasing regulatory T cell populations. Additionally, microbial-derived metabolites such as secondary bile acids and trimethylamine-N-oxide (TMAO) have been linked to carcinogenic processes. Conversely, protective microbiota, including Lactobacillus, Bifidobacterium, and Faecalibacterium prausnitzii, contribute to intestinal homeostasis by producing short-chain fatty acids (SCFAs) like butyrate, which exhibit anti-inflammatory and anti-carcinogenic properties. These beneficial microbes enhance gut barrier integrity, modulate immune responses, and inhibit tumor cell proliferation. Understanding the dynamic interplay between pathogenic and protective microbiota is essential for developing microbiome-based interventions, such as probiotics, prebiotics, and fecal microbiota transplantation, to prevent or treat CRC. Future research should focus on identifying microbial biomarkers for early CRC detection and exploring personalized microbiome-targeted therapies. A deeper understanding of host–microbiota interactions may lead to innovative strategies for CRC management and improved patient outcomes. Full article