Background: The disruption of the intestinal barrier and the imbalance of the gut microbiota (GM) seem to play a major role in the complex pathogenesis of irritable bowel syndrome (IBS). Specific microbial strains could improve the gut microenvironment, promoting anti-inflammatory pathways; similarly, vitamin D supplementation could play a role in enhancing the barrier integrity and modulating the immune response in the gut. This study aims to evaluate the efficacy of a new multistrain probiotic, combined with vitamin D, in improving gut barrier function in IBS without constipation. Methods: In this phase IIb double-blind randomized placebo-controlled, parallel-group, multicenter, clinical trial, 35 patients were treated for 12 weeks with OttaBac^®, a high concentration multistrain probiotic plus cholecalciferol, or placebo and were followed up until week 16. Symptoms, quality of life, intestinal permeability, fecal biomarkers, and microbiota composition were evaluated at 0, 12, and 16 weeks. Results: Mean zonulin values showed a significant progressive reduction in the active group (−10.2 ng/mL at week 12, p = 0.0375; −19.5 ng/mL at week 16, p = 0.0002), with a significant difference between groups at week 16 in the per-protocol population (−19.01, p = 0.0053). The active group showed a more stable trend toward improvement in stool frequency and consistency at both week 12 and 16, with a significant improvement compared to the baseline and to the placebo group (−23.2, p = 0.0265, and 5.57 vs. −23.2, p = 0.0492, respectively). No differences were found in regards to the lactulose/mannitol ratio, Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) and Short Form Health Survey (SF-36) total scores, plasmalemmal vesicle associated protein-1 (PV-1), and citrulline levels. In the active group, Bifidobacterium animalis subsp. lactis and Streptococcus thermophilus levels were increased (p < 0.05), while those for Lachnospira were decreased (p < 0.05), and significant changes in Actinobacteria and Proteobacteria were observed (p < 0.05). Lactate (p < 0.01) and acetate (p < 0.05) levels increased post-treatment. Correlation analysis pointed out a significant association between the microbial biomarkers and the symptoms (p < 0.05). Conclusions: Probiotic plus vitamin D could improve IBS-associated symptoms through gut microbiota modulation and gut barrier enhancement, with persistent benefits after treatment discontinuation.

Ischemic stroke (IS) can be caused by perturbations of the gut–brain axis. An imbalance in the gut microbiota (GM), or dysbiosis, may be linked to several IS risk factors and can influence the brain through the production of different metabolites, such as short-chain fatty acids (SCFAs), indole and derivatives. This study examines ecological changes in the GM and its metabolic activities after stroke. Fecal samples of 10 IS patients were compared to 21 healthy controls (CTRLs). GM ecological profiles were generated via 16S rRNA taxonomy as functional profiles using metabolomics analysis performed with a gas chromatograph coupled to a mass spectrometer (GC-MS). Additionally fecal zonulin, a marker of gut permeability, was measured using an enzyme-linked immuno assay (ELISA). Data were analyzed using univariate and multivariate statistical analyses and correlated with clinical features and biochemical variables using correlation and nonparametric tests. Metabolomic analyses, carried out on a subject subgroup, revealed a high concentration of fecal metabolites, such as SCFAs, in the GM of IS patients, which was corroborated by the enrichment of SCFA-producing bacterial genera such as Bacteroides, Christensellaceae, Alistipes and Akkermansia. Conversely, indole and 3-methyl indole (skatole) decreased compared to a subset of six CTRLs. This study illustrates how IS might affect the gut microbial milieu and may suggest potential microbial and metabolic biomarkers of IS. Expanded populations of Akkermansia and enrichment of acetic acid could be considered potential disease phenotype signatures.

Recent evidence indicates that the gut microbiota (GM) has a significant impact on the inflammatory bowel disease (IBD) progression. Our aim was to investigate the GM profiles, the Microbial Dysbiosis Index (MDI) and the intestinal microbiota-associated markers in relation to IBD clinical characteristics and disease state. We performed 16S rRNA metataxonomy on both stools and ileal biopsies, metabolic dysbiosis tests on urine and intestinal permeability and mucosal immunity activation tests on the stools of 35 IBD paediatric patients. On the GM profile, we assigned the MDI to each patient. In the statistical analyses, the MDI was correlated with clinical parameters and intestinal microbial-associated markers. In IBD patients with high MDI, Gemellaceae and Enterobacteriaceae were increased in stools, and Fusobacterium, Haemophilus and Veillonella were increased in ileal biopsies. Ruminococcaceae and WAL_1855D were enriched in active disease condition; the last one was also positively correlated to MDI. Furthermore, the MDI results correlated with PUCAI and Matts scores in ulcerative colitis patients (UC). Finally, in our patients, we detected metabolic dysbiosis, intestinal permeability and mucosal immunity activation. In conclusion, the MDI showed a strong association with both severity and activity of IBD and a positive correlation with clinical scores, especially in UC. Thus, this evidence could be a useful tool for the diagnosis and prognosis of IBD.

Background/Objectives: The gut microbiota (GM) is pivotal for immune regulation, metabolism, and neurodevelopment. Infants undergoing surgery for congenital gastrointestinal anomalies are especially prone to microbial imbalances, with a paucity of beneficial bacteria (e.g., Bifidobacteria and Bacteroides) and diminished short-chain fatty acid production. Dysbiosis has been associated with severe complications, including necrotizing enterocolitis, sepsis, and feeding intolerance. This narrative review aims to critically examine strategies for microbiota modulation in this high-risk cohort. Methods: An extensive literature analysis was performed to compare the evolution of GM in healthy neonates versus those requiring gastrointestinal surgery, synthetizing strategies to maintain eubiosis, such as early nutritional interventions—particularly the use of human milk—along with antibiotic management and supplementary treatments including probiotics, prebiotics, postbiotics, and lactoferrin. Emerging techniques in metagenomic and metabolomic analysis were also evaluated for their potential to elucidate microbial dynamics in these patients. Results: Neonates undergoing gastrointestinal surgery exhibit significant alterations in microbial communities, characterized by reduced levels of eubiotic bacteria and an overrepresentation of opportunistic pathogens. Early initiation of enteral feeding with human milk and careful antibiotic stewardship are linked to improved microbial balance. Adjunctive therapies, such as the administration of probiotics and lactoferrin, show potential in enhancing gut barrier function and immune modulation, although confirmation through larger-scale studies remains necessary. Conclusions: Modulating the GM emerges as a promising strategy to ameliorate outcome in neonates with congenital gastrointestinal surgical conditions. Future research should focus on the development of standardized therapeutic protocols and the execution of rigorous multicenter trials to validate the efficacy and safety of these interventions.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder. Investigations of gut microbiota (GM) play an important role in deciphering disease severity and symptoms. Overall, we stratified 70 ASD patients by neuropsychological assessment, based on Calibrated Severity Scores (CSSs) of the Autism Diagnostic Observation Schedule-Second edition (ADOS-2), Child Behavior Checklist (CBCL) and intelligent quotient/developmental quotient (IQ/DQ) parameters. Hence, metataxonomy and PICRUSt-based KEGG predictions of fecal GM were assessed for each clinical subset. Here, 60% of ASD patients showed mild to moderate autism, while the remaining 40% showed severe symptoms; 23% showed no clinical symptoms, 21% had a risk of behavior problems and 56% had clinical symptoms based on the CBCL, which assesses internalizing problems; further, 52% had no clinical symptoms, 21% showed risk, and 26% had clinical symptoms classified by CBCL externalizing problems. Considering the total CBCL index, 34% showed no clinical symptoms, 13% showed risk, and 52% had clinical symptoms. Here, 70% of ASD patients showed cognitive impairment/developmental delay (CI/DD). The GM of ASDs with severe autism was characterized by an increase in Veillonella, a decrease in Monoglobus pectinilyticus and a higher microbial dysbiosis index (MDI) when compared to mild-moderate ASDs. Patients at risk for behavior problems and showing clinical symptoms were characterized by a GM with an increase of Clostridium, Eggerthella, Blautia, Intestinibacter, Coprococcus, Ruminococcus, Onthenecus and Bariatricus, respectively. Peptidoglycan biosynthesis and biofilm formation KEGGs characterized patients with clinical symptoms, while potential microbiota-activated PPAR-γ-signaling was seen in CI/DD patients. This evidence derived from GM profiling may be used to further improve ASD understanding, leasing to a better comprehension of the neurological phenotype.

Short-chain fatty acids (SCFAs) are key biomarkers of gut microbiota and intestinal health, yet their analysis is challenging due to high volatility, hydrophilicity, and the complexity of the faecal matrix. This study introduces a novel, green, and fully automated workflow for monitoring SCFAs in faecal water samples. It combines microwave-assisted derivatisation, vacuum-assisted cooling multiple solid-phase microextraction (Vac-HS-cooling-MSPME), and fast gas chromatography–mass spectrometry (GC-MS). On-sample derivatisation with 2,3,4,5,6-pentafluorobenzyl bromide was optimised via design of experiments, reducing reaction time from 3 h to just 2 min at 100 °C while preserving high yields and selectivity. Integration of Vac-HS-cooling-MSPME with a fast GC column (5 m × 0.1 mm ID × 0.4 µm) increased sample throughput from two to approximately six samples per hour, with total chromatographic times of 5.24 min. MSPME specifically improved sensitivity for low-response analytes such as pentafluorobenzyl formate. The method demonstrated excellent linearity (R² > 0.998), low limits of detection (0.002–0.09 mg/L), good intra- and inter-day precision, accuracies exceeding 85%, and consistent recovery for each analyte (86–90%). The AGREE greenness score improved from 0.65 to 0.68, confirming alignment with green analytical chemistry principles. This system offers a high-throughput, sensitive, and eco-friendly tool for SCFA quantification, confirmed by the application on real paediatric faecal water samples.