Declining cognitive function in older adults may be linked to reduced nitric oxide (NO) bioavailability, which is supported by oral nitrate-reducing bacteria. Oral microbiome community structure varies geographically, complicating understanding of microbiome-cognition relationships across populations. This study aimed to identify consistent associations between the oral microbiome and cognitive function across two geographically distinct cohorts from the UK and Belgium, and to explore age-related differences in NO biomarkers, cognitive performance, and microbiome composition using 16S rRNA sequencing. Sixty healthy participants (15 young and 15 older adults per location) completed a cognitive test battery, blood pressure measurements, plasma and saliva collection for nitrate and nitrite analysis, and a tongue swab for oral microbiome assessment. Despite geographical differences in oral microbiome composition (PERMANOVA P = 0.04), age-related microbial shifts were consistent across geographic cohorts, including enrichment of Treponema and Tannerella in older adults. Nitrate-reducing taxa such as Haemophilus parainfluenzae and Neisseria flavescens were consistently associated with cognitive performance measures in both cohorts (P < 0.05). In the UK, higher plasma [nitrate] was associated with improved Digit Symbol Substitution Test (DSST) accuracy (β = 19.2, P < 0.01) and reaction times (β = -3444 ms, P < 0.05), but poorer Emotion Recognition Task (ERT) accuracy (β = -5.219, P < 0.05), while UK plasma [nitrite] was associated with slower Balloon Analog Risk Task (BART; β = 2277 ms, P < 0.001) and ERT (β = 8577 ms, P < 0.05) reaction times. In Belgium, saliva [nitrate] was associated with slower Visual Object Learning Test (VOLT) reaction times (β = 202 ms, P < 0.05), while in the UK, saliva [nitrite] correlated with slower BART (β = 111 ms, P < 0.05) and LOT (β = 1888 ms, P < 0.01). Overall, geography emerged as a major driver of oral microbiome variation, yet consistent age-related microbial and cognitive associations were preserved across populations. These findings emphasise the need to account for geographic context in microbiome-health research. A better understanding of oral microbial patterns may help inform future mechanistic or interventional studies to promote cognitive health in ageing.

Acute otitis media (AOM) is one of the most prevalent infectious diseases in childhood, with Streptococcus pneumoniae and Haemophilus influenzae being the most commonly involved pathogens. Following the coronavirus disease 2019 (COVID-19) pandemic and the incorporation of 13-valent pneumococcal conjugate vaccine (PCV13) into the national immunization program, changes in pneumococcal invasive disease have been described, but data on AOM remain limited. This study aimed to evaluate the current bacterial etiology of pediatric AOM. Spontaneous otorrhea fluid (SOF) samples and optional nasopharyngeal samples (NP) were collected from children with AOM attending 13 primary care centers in southern Barcelona. Conventional culture and PCR were used for pathogen detection. Most frequent pathogens (Streptococcus pyogenes, S. pneumoniae, and H. influenzae) underwent antimicrobial susceptibility testing and whole-genome sequencing. A total of 145 SOF and 83 NP samples were obtained. Bacterial growth in SOF samples was detected by culture in 80.7% of the samples and by molecular methods in 91.7%. The predominant pathogens were H. influenzae (40.7%), S. pyogenes (35.2%), and S. pneumoniae (33.8%). Serotype 3 (mainly GPSC12-CC180) was the most frequent pneumococcal serotype (15.6%), and 23.8% of identified serotypes were included in PCV13 despite high vaccination coverage. Most of the S. pyogenes analyzed (43.1%) belonged to the emm1-ST28 genotype, and 94.1% of H. influenzae isolates analyzed were non-typeable. These findings demonstrate a marked shift in AOM etiology in the post-PCV13 era, with H. influenzae emerging as the leading pathogen and an increase in S. pyogenes AOM. Continued surveillance is essential to inform future vaccination and prevention strategies.

We report a cutaneous ulcer outbreak in Sierra Leone in 2025 that predominantly affected ≈403 schoolchildren. The causative agent was confirmed as Haemophilus ducreyi, a bacterium traditionally associated with the sexually transmitted infection chancroid but more recently recognized as an emerging cause of lower limb cutaneous ulcers in tropical regions.

Glässer's disease, caused by Glaesserella parasuis (GPS), causes substantial economic losses in the swine industry worldwide. This situation is largely attributable to the poor cross-protective efficacy of currently available vaccines. In this study, a multi-antigen cocktail subunit vaccine against GPS infection was developed. In silico antigenicity analysis, the immunoprotective efficacy, and antibody titers of 14 GPS antigens were assessed in a murine model. Finally, VacJ, PtsG, and GAPDH were identified as the component of the cocktail vaccine, with Gel-01 as the optimal adjuvant. Immunization of the cocktail vaccine induced robust humoral and cellular immune responses. The vaccine conferred effective cross-protection against lethal-dose GPS4 and GPS5 infections in mice. As supported by a pilot study, it also demonstrated favorable immunoprotective efficacy against GPS infection in piglets. Furthermore, immune sera from vaccinated mice significantly inhibited the growth of GPS4 and GPS5. Overall, these results suggested that the subunit cocktail vaccine established in this study exhibits great potential for preventing GPS infection under experimental conditions, and further large‑scale pig trials are still required to validate its practical applicability in field production.

Non-typeable Haemophilus influenzae (NTHi) is an opportunistic extracellular pathogen associated with various respiratory diseases. To combat host antimicrobial peptides, NTHi has developed a specialized transporter named Sap (sensitivity to antimicrobial peptide). Within this transporter, the HiSapF component functions as a nucleotide-binding domain (NBD). Despite its significant role, the structural and functional characteristics of HiSapF remained unexplored. In this study, we present the crystal structure of HiSapF (2.3 Å resolution) from NTHi, which features nine α-helices and nine β-sheets, including three conserved antiparallel β-sheets (β1-β2-β3) in the N-terminal region. Key structural features (Walker A and B motifs, Q loop, D loop, and signature motifs) are conserved in HiSapF, aligning with known NBDs. Computational and biophysical analyses indicated that HiSapF can possibly self-associate to dimerize under the tested conditions. Further comparative molecular docking, dynamic simulations, and mutational studies reveal that the residues from Walker A and B motifs of HiSapF are essential for interacting with ATPMg[2+]. Specifically, the Walker A residues primarily engage the adenosine group, while the Walker B residues (conserved residue Asp173), identified as crucial for coordinating the Mg[2+] ion of the ATP molecule for hydrolysis (Km: ∼2.34 ± 0.32 mM; kcat: ∼0.025 s[-1]). Novobiocin, identified as a potential inhibitor of HiSapF, demonstrates a putative allosteric-binding site and can reduce ATPase activity; further structural and biochemical studies can enhance our understanding. Collectively, these findings offer important structural and functional insights into HiSapF and may facilitate further investigation for the development of inhibitors targeting NBDs against bacterial transporters.

Background/Objectives: In this exploratory longitudinal study, we examined dietary intake and gut microbiota across preparation, competition, and transition phases in competitive long-distance runners and explored microbial patterns associated with phase-specific dietary intake. Methods: Seven competitive long-distance runners were assessed across three training phases. At each phase, dietary intake and body composition were assessed, and fecal samples were collected. Gut microbiota composition was analyzed using 16S rRNA gene sequencing. Phase-related taxonomic differences were evaluated using repeated-measures approaches with multiple-testing correction, and differential abundance analysis was performed using DESeq2 with participant identity included as a blocking factor. Additionally, exploratory k-means clustering based on energy, carbohydrate, and protein intake was used to characterize dietary intake patterns. Results: Energy, protein, and fat intake differed significantly across training phases, whereas carbohydrate intake did not reach statistical significance. Exploratory alpha- and beta-diversity analyses yielded no statistically detectable differences across phases. At the phylum level, Synergistetes showed an overall phase effect after FDR correction, although no pairwise comparison remained significant after Bonferroni adjustment. In the DESeq2 analysis, Haemophilus was more abundant during the transition than preparation phase, Enterococcus was more abundant during preparation than transition, and Cronobacter was more abundant during preparation than competition (all adjusted p < 0.05). Exploratory dietary clustering identified additional cluster-associated microbial differences, but cluster membership substantially overlapped with the training phase. Conclusions: Dietary intake varied across the competitive training cycle. Community-level diversity results were presented for exploratory purposes only in this small cohort. A limited number of taxa showed phase-related differences after multiple-testing correction. Because dietary intake and training phase changed concurrently, the cluster-associated microbial findings should be interpreted as exploratory patterns within the combined nutritional and training context rather than as independent dietary effects.

Cystic fibrosis (CF) is a genetic disorder caused by CFTR gene mutations. The elexacaftor/tezacaftor/ivacaftor (ETI) drug combination has markedly improved CF outcomes; however, its impact on gut microbiota (GM) dysbiosis remains poorly investigated. Herein, we examined potential longitudinal effects of ETI treatment on six CF patients' GM before therapy (T0), and after 6 (T1) and 12 months (T2). Patients' stools were analyzed using 16S rRNA metataxonomy, and GM profiling was characterized by alpha diversity, performed using the Shannon-Weiner, Simpson, and Chao1 indices; beta diversity, based on Bray-Curtis distance; and taxonomic patterns through multivariate and univariate analyses. A longitudinal exploratory assessment of the GM composition of CF patients at T0, T1, and T2 was performed. At baseline, CF patients displayed a distinct genus-level microbial signature compared with healthy controls, including Veillonella_A, Haemophilus_D_735815, Fusobacterium_C, Ruminococcus_B, and Blautia_A_141780. During ETI treatment, alpha diversity showed no significant transient increase at T1 followed by a decrease at T2. Taxonomic profiles showed marked inter-individual heterogeneity. Exploratory longitudinal analyses, assessed by the Friedman test, identified temporal variation in 11 bacterial genera: CAG-177, Clostridium_AP, Coprococcus_A_121497, Copromonas, and Muricomes_149725, showed a progressive decrease in relative abundance from T0 to T2; Haemophilus_D_734546, Eubacterium_B, Lachnoanaerobaculum, Moraxella_C_651924, and Neisseria_563205 displayed a transient increase at T1, followed by a decrease at T2; and Lactococcus_A_346120 showed a transient decrease at T1 followed by an increase at T2. Progressive depletion and transient changes or recovery of bacterial taxa may only represent a rough idea of the ecological changes in the gut microbiota observed during the course of ETI therapy. Longitudinally studies based on large cohorts of CF patients are mandatory to properly interpret these very preliminary results and to search for actual ETI-induced microbiome effects.

Pulmonary hypertension complicating chronic obstructive pulmonary disease (COPD-PH) has a worse prognosis than airflow limitation alone but its pathogenesis is thought to be primarily due to alveolar hypoxia affecting pulmonary circulation. Two observations are not fully explained by this model. First, the majority of exacerbations of COPD are infectious and there is a stable frequent-exacerbator phenotype that is not fully accounted for by spirometric severity. Second, the airways of COPD are not sterile. They are home to a resident microbial community that changes as the disease progresses and the gut microbial community also undergoes disease-associated changes. This review examines whether microbial factors actively contribute to pulmonary vascular remodelling or merely reflect advanced disease. Three candidate exposures are considered: chronic airway colonisation, dysbiosis of the airway and gut communities and recurrent infectious exacerbation. We then examine the virulence mechanisms and host-recognition pathways of non-typeable Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, Pseudomonas aeruginosa, rhinovirus, influenza viruses, respiratory syncytial virus and SARS-CoV-2. We then trace the pathways linking microbial recognition to vascular injury: Toll-like receptor signalling and NF-κB activation; interleukin-6, tumour necrosis factor-α and interleukin-1β; endothelin-1 upregulation against nitric oxide depletion; reactive oxygen species and hypoxia-inducible factor signalling converging with hypoxic pulmonary vasoconstriction; and, along the gut-lung axis, lipopolysaccharide translocation, trimethylamine N-oxide and depletion of short-chain fatty acid-producing taxa. Therapeutically, there is evidence and a vascular rationale for interventions that decrease exacerbation frequency. Pulmonary vasodilators have a sound physiological rationale, although their clinical efficacy is frequently limited by worsening ventilation-perfusion mismatch. Current evidence supports biological plausibility rather than demonstrated causality: no direct longitudinal human study has established that microbial alterations or microbial exposure cause pulmonary vascular remodelling in COPD-PH. We identify study designs capable of directly testing this hypothesis.