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The Effect of Colesevelam on the Microbiome in Postoperative Crohn's Disease.

BACKGROUND: While surgery plays a pivotal role in the management of ileal Crohn's disease, the risk of endoscopic recurrence following an ileocaecal resection can be greater than 65% within 12 months of surgery. More than 90% of patients with Crohn's disease have a concomitant diagnosis of bile acid diarrhea following an ileal resection. This pilot study aimed to assess whether the use of bile acid sequestrants in patients with Crohn's disease who have undergone a primary terminal ileal resection with concomitant bile acid diarrhea can alter the microbiome and prevent disease recurrence. METHODS: Patients with Crohn's disease who underwent a primary terminal ileal resection and had symptoms of diarrhea within 1-3 months of surgery underwent 75SeHCAT testing for bile acid diarrhea. If positive (75SeHCAT&#x2005;&#x2264;&#x2005;15%), patients were treated with colesevelam and stool samples were collected at 4 weeks, 8 weeks, and 6-12 months posttreatment. If negative (75SeHCAT&#x2005;>&#x2005;15%), treatment was not given and were reviewed in the clinic as per local guidelines. All patients underwent a 6-12 month postoperative colonoscopy where further stool samples and mucosal biopsies were taken. Disease activity was established using the endoscopic Rutgeert's score, with disease remission defined as Rutgeert's score <i2 and disease recurrence &#x2265;i2. 16S ribosomal RNA gene analysis was undertaken for the collected fecal and mucosal samples to assess &#x3b1;/&#x3b2;-diversity and microbial composition. RESULTS: A total of 14 patients who completed the study, 10 of whom had a 75SeHCAT positive diagnosis of bile acid diarrhea and were started on treatment with colesevelam. Four patients did not require treatment as 3 were asymptomatic and 1 had a negative 75SeHCAT scan. Three of the fourteen patients had disease recurrence at their 6-12 month postoperative colonoscopy assessment, of which 1 patient was taking colesevelam and 2 patients were not taking colesevelam. A total of 44 fecal samples and 44 mucosal biopsies underwent 16S ribosomal RNA gene analysis to assess &#x3b1;/&#x3b2;-diversity and microbial composition. In the colesevelam treated patients there was no significant difference in &#x3b1;/&#x3b2;-diversity pre- and posttreatment. Pretreatment, the 3 most abundant bacterial classes in all patients were Bacteroidia, Clostridia, and Gammaproteobacteria. Following 6-12 months of treatment, out of the 9 patients on colesevelam, 5/9 (55.6%) had a reduction in Bacteroidia, 9/9 (100%) had an increase in Clostridia, and 7/9 (77.8%) had a reduction in Gammaproteobacteria. Of the 2 patients not given colesevelam, one showed a reduction in Bacteroidia, increase in Clostridia and a reduction in Gammaproteobacteria. CONCLUSIONS: This small pilot study demonstrated that patients who were given colesevelam, were more likely to be in disease remission at their 6-12 months colonoscopy review compared with those not treated. Furthermore, treatment with colesevelam may have a role in altering the microbiome to help maintain remission states in postoperative Crohn's disease. Larger mechanistic studies are now needed to confirm these findings and demonstrate statistical significance as well as investigate whether this benefit may be present even in those patients with 75SeHCAT negative disease.

Humans↗

Gut Colonization With Vancomycin-Resistant Enterococcus Shapes the Gut Microbiome in the Intensive Care Unit.

BACKGROUND: Gut pathogen colonization with vancomycin-resistant Enterococcus (VRE) is common in the intensive care unit (ICU) and is associated with worse clinical outcomes; however, the timing of VRE colonization and its collateral effects on the gut microbiome are incompletely understood. METHODS: Medical ICU patients admitted with sepsis and receiving broad-spectrum antibiotics were sampled via deep rectal swabs at ICU admission and on ICU day 3, 7, 14, and 30. Rectal swabs were cultured for VRE on selective media and analyzed via 16S ribosomal RNA gene sequencing. RESULTS: Ninety patients were sampled (340 longitudinal swabs). VRE positivity rose from 20% at ICU admission to a peak of 33% by ICU day 14 and then modestly declined to 31% by ICU day 30. Paralleling this, alpha diversity fell while Enterococcus relative abundance rose through ICU day 14 with both returning to baseline by ICU day 30. The median relative abundance of Enterococcus was 38% (interquartile range [IQR], 7.4%-75%) for VRE-positive samples compared to 0.01% (IQR, 0%-19%) for VRE-negative samples (rank-sum P < .01); 38 samples had &#x2265;90% Enterococcus and 8 samples were 100% Enterococcus by sequencing. VRE was associated with lower alpha diversity (median Shannon index 1.90 [IQR, 0.89-2.66] if VRE positive versus 2.64 [IQR, 1.58-3.22] if VRE negative; P < .01). CONCLUSIONS: VRE gut colonization peaked at ICU day 14 followed by a modest decline and was associated with low alpha diversity. Improved understanding of dynamic changes in the gut microbiome may facilitate successful future ICU interventions. CLINICAL TRIALS REGISTRATION: NCT03865706.

Aged↗

Function-based selection of synthetic communities enables mechanistic microbiome studies.

Understanding the complex interactions between microbes and their environment requires robust model systems such as synthetic communities (SynComs). We developed a functionally directed approach to generate SynComs by selecting strains that encode key functions identified in metagenomes. This approach enables the rapid construction of SynComs tailored to any ecosystem. To optimize community design, we implemented genome-scale metabolic models, providing in silico evidence for cooperative strain coexistence prior to experimental validation. Using this strategy, we designed multiple host-specific SynComs, including those for the rumen, mouse, and human microbiomes. By weighting functions differentially enriched in diseased versus healthy individuals, we constructed SynComs that capture complex host-microbe interactions. We designed an inflammatory bowel disease SynCom of 10 members that successfully induced colitis in gnotobiotic IL10-/- mice, demonstrating the potential of this method to model disease-associated microbiomes. Our study establishes a framework for designing functionally representative SynComs of any microbial ecosystem, facilitating mechanistic study.

Animals↗

Leveraging chemical synthesis to discover metabolites from the gut microbiome.

The gut microbiome has the biosynthetic potential to make a variety of secondary metabolites or natural products, which serve as molecular messages between cells and organisms. These chemical signals are capable of affecting physiology and behavior in real time, and are, therefore, bioactive and can exhibit medicinal properties including anticancer, antimicrobial, or immunomodulating activities. It is clearly important to identify signaling molecules in the human gut, but elucidating their chemical structures can be challenging since traditional isolation methods are typically not available. The discovery of microbiome-related metabolites requires multidisciplinary collaboration, where chemical synthesis often plays an essential role. This review highlights examples where synthetic chemistry was used to study novel metabolites produced by the gut microbiota. In the first part, we describe examples where organic synthesis was utilized in traditional contexts, as a last step for validating structures and sourcing material for biological testing. The final section of this review discusses next-generation applications for chemical synthesis, where integration with metabolomic or genomic analysis simultaneously uncovers both structural and biological information about small molecules from the gut.

Gastrointestinal Microbiome↗

Association between the gut microbiome and plasma metabolites linked to vocalization-based temperament in Merino sheep.

BACKGROUND: Temperament, as a determinant of behavioural and emotional responses, has a substantial adaptive value in different environments. This study aims to investigate the association between the gut microbiota and temperament plasticity, and clarify the potential metabolic mechanism that underpins that association by running a multi-omics study in sheep. METHODS: The TrackSheep research cohort was generated using 200 healthy juvenile Merino ewes, and the rumen microbiota, plasma metabolome, and temperament phenotype was measured. RESULTS: Rumen metagenomic analysis identified 25 microbial species and 16 MetaCyc pathways that explained 37.5% and 11.1%, respectively, of the variation in temperament as estimated using the vocal reactivity to stress. Among these, the &#x3b3;-aminobutyric acid (GABA) shunt and allantoin degradation pathways showed the strongest associations with vocal behaviour. Multi-omic integration linked these microbial pathways to plasma metabolites that are involved in neurotransmission, antioxidant defense, and energy metabolism, including acetyl-L-carnitine (ALCAR) and urocortisone, which partially mediated the effects of microbial pathways on vocalisations. Notably, functional genomic and mediation analyses indicated that the abundance of Cryptobacteroides sp902761655 was associated with the activity of GABA shunt pathway, where GABA co-occurred with succinate production, in turn correlating with reduced inhibitory effects of ALCAR on stress-susceptible temperament. Although plasma metabolite shifts observed immediately after behavioural tests reflected stress exposure, their associations with rumen microbiota highlight microbiome-metabolite interplay that could underly behavioural variation. CONCLUSIONS: Our study provides the first large-scale multi-omics evidence linking the rumen microbiome to a dimension of emotional reactivity in livestock, while underscoring the need for longitudinal and experimental validation to establish causal mechanisms. Video Abstract.

Animals↗

Hospitalization throws the preterm gut microbiome off-key.

Environmental exposures substantially influence the infant gut microbiome. In this issue of Cell Host & Microbe, Th&#xe4;nert et&#xa0;al.1 characterize how medical interventions in the neonatal intensive care unit (NICU) shape gut microbiome dynamics in the first months of life by analyzing over 2,500 fecal samples with metagenomics and metatranscriptomics.

Gastrointestinal Microbiome↗

Comprehensive Microbiome Analyses for Regenerative Endodontic Therapy.

INTRODUCTION: Comprehensive microbiome analyses include the study of all microbial taxa, including bacteria, archaea, viruses, and fungi, as well as their functional activities and antibiotic resistance gene expression. Regenerative endodontic therapy presents a clinical situation where the most effective antimicrobial approaches are needed in order to ensure clinical success. METHODS AND RESULTS: In this paper, different contemporary technologies for the identification of endodontic microorganisms, such as with next generation sequencing, and their functional characterization, such as with whole genome sequencing, are described. The role of transcriptomics, as well as resistome analysis, are also discussed. Furthermore, the manner in which all this work and knowledge could be incorporated into clinical endodontics in general, and regenerative endodontic therapy as a special treatment, is outlined. CONCLUSIONS: Comprehensive microbiome analysis can lead to the development of more effective and personalized antimicrobial treatment.

Endodontics↗

A streamlined workflow for high throughput metaproteomic analysis of the rumen microbiome.

Metaproteomics can provide direct functional insights into complex microbial communities, yet its application in rumen research remains limited due to labor-intensive and low-throughput sample preparation workflows before the MS analysis. This work aimed to develop and characterize a streamlined, high throughput metaproteomic workflow optimized for rumen samples. Key steps, including microbial cell extraction, cell lysis, protein digestion, and LC-MS/MS acquisition, were systematically assessed and optimized to reduce hands-on time while maintaining deep proteome coverage. The optimized workflow integrates a minimized cell extraction protocol using 0.5&#xa0;g starting material and in-solution tryptic digestion. Application of the final workflow to 72 samples from in vitro fermentation revealed that biological variability between inocula dominated technical variability, which remained moderate (median CV of 21-24% across batches). Overall, the optimized workflow supports robust taxonomic and functional characterization of the rumen microbiome with improved scalability. These advances provide a foundation for applying metaproteomics to larger experimental designs, including nutritional trials and cohort studies, thereby enabling broader functional interrogation of rumen microbial ecosystems. SIGNIFICANCE: This study addresses current limitations in the application of metaproteomics to rumen microbiome research by developing a streamlined and scalable sample preparation workflow. By optimizing key steps and reducing sample input while maintaining reproducibility and proteome coverage, this work enables more efficient processing of larger sample sets. These advances support the broader use of metaproteomics in rumen studies and facilitate functional investigations relevant to animal nutrition and sustainable livestock production.

Animals↗

Impact of the maternal microbiome on neonatal immune development.

Historically, multigenerational health and disease transmission have primarily focused on genetic inheritance. However, the discovery that beneficial microorganisms known as commensal microbiota outnumber human genes tenfold has reshaped this perspective, highlighting their critical role in maintaining homeostasis and protecting against pathogens. Unlike the human genome, commensal microbiota is not genetically inherited but is acquired anew with each generation. with initial gut colonization playing a pivotal role in shaping an infant's immune system, neurodevelopment, and long-term health, all heavily influenced by maternal factors. In this review, we examine emerging research on maternal microbial influences on the fetus beginning in utero. We provide an updated overview of the current insights into the impact of the vaginal microbiome during parturition on offspring immunity and discuss the potential long-term health implications for infants born via cesarean section. We explore the advantages and limitations of techniques designed to mitigate these effects, such as vaginal seeding and emphasize that the development of the neonatal immune system is a dynamic process influenced by maternal factors beyond birth, including the transfer of microbiota through breast milk and skin contact. Finally, we present gaps in current research and propose future research directions to deepen our understanding of the impacts of the maternal microbiome on her child. Together, these insights demonstrate how maternal influence on offspring health and immunity extends beyond genetic factors, encompassing the transmission of microbiota, which, in turn, has profound long-term implications for health and disease resilience, offering a novel perspective on intergenerational health dynamics.

Humans↗

Intestinal microbiome changes in response to amino acid and micronutrient supplementation: secondary analysis of the AMAZE trial.

Microbial dysbiosis has been linked to environmental enteropathy (EE) and alterations in nutrient absorption; however, compositional modifications following exposure to supplementary nutrients are poorly understood. Here, we report the effect of amino acid and micronutrient supplementation on the gut microbiome of adults with EE. In the AMAZE trial, adults with EE were randomized to amino acids (AA) and/or micronutrients (MM) for 16&#xa0;weeks in a 2&#xa0;&#xd7;&#xa0;2 factorial design against placebo. Endoscopy was performed before and after intervention, during which duodenal aspirates were collected as well as fecal samples. 16S rRNA amplicon sequencing was performed on both these samples, and differences in bacterial community composition before and after interventions were investigated using differential abundance analysis, corrected using false discovery rate, plus alpha and beta diversity measurements. HIV seropositive participants exhibited lower alpha and beta diversity at baseline. AA and/or MM supplementation did not show significant changes in abundance or diversity of genera post-intervention compared to placebo. Micronutrient supplementation resulted in an increase in the pyruvate fermentation to acetone MetaCyc pathways compared to the placebo arm. This study provides insights into the responsiveness of the gut microbiome to micronutrient and amino acid supplementation in adults with EE.

HIV↗

Microbiome features associated with persistent intestinal carriages of Escherichia coli ST131 in a Southeast Asian cohort study.

Escherichia coli sequence-type 131 (ST131) is the dominant global extraintestinal pathogen capable of asymptomatic intestinal carriage and sustained household transmission, challenging infection control. Despite its clinical significance, the ecological determinants of gut persistence remain poorly understood. We performed shotgun metagenomics on fecal samples to investigate gut microbiome features associated with ST131-positive samples, distinct host carrier statuses (persistent, intermittent and non-carriers) and household risks in a study of a Southeast Asian cohort. Here, we show that ST131 carriage was associated with compositional shifts without reducing species alpha-diversity. Regression analyses identified depletion of commensal taxa and the 1,5-anhydrofructose degradation pathway in ST131-positive samples. Persistent carriers exhibited highly perturbed microbiome enriched with pathobionts, aerobactin- and lipopolysaccharide (LPS)-biosynthesis pathways. Comparing household risk groups to control, revealed that biotin biosynthesis and 1,5-anhydrofructose degradation may influence ST131 co-colonization through both direct and indirect mechanisms. Machine learning analyses identified metabolic pathways as stronger discriminators of persistent carriage than taxonomic features. Genomic-resolved analysis of clinical ST131 isolates revealed conserved genes for iron-acquisition, LPS and antibiotic resistance determinants. Overall, while commensals and metabolism may influence initial ST131 colonization, persistent carriage is associated with specific microbial and metabolic adaptations, providing potential targets to limit intestinal ST131 persistence.

Humans↗

Dual-approach analysis of gut microbiome in patients with type 1 diabetes and diabetic kidney disease.

BACKGROUND: Type 1 diabetes (T1D) is a multifactorial autoimmune disease mediated by genetic, epigenetic, and environmental factors. Diabetic kidney disease (DKD) is a major complication of diabetes mellitus which affects 30-40% of T1D patients. Increasing evidence suggests the significant role of the microbiome in the progression of both T1D and DKD. MATERIALS AND METHODS: Here we recruited 76 T1D patients and 22 healthy controls and combined data from sigmoid colon biopsy samples analysed with V3-V4 region amplification of 16S rRNA gene and shotgun metagenomics data obtained from faecal samples. Additionally, we compared T1D patients with and without progression of DKD. RESULTS: We observed significant differences within both sample types at various taxonomic and functional levels. T1D patient microbiota detected using biopsy samples had a lower abundance of the Bacteroides genus when compared to healthy controls. Significantly, despite only a few taxonomic differences patients with and without DKD progression were vastly different at the functional pathway level within the faecal samples - we observed 2 and 61 enriched pathways in these groups. respectively, with several of these pathways linked to the mediation of renal function. CONCLUSION: Altogether, we present novel data about microbial signatures relevant to T1D and DKD progression, which partly supports previous data and also presents possible tissue type or population-specific elements. DKD progression is characterized with significant differences within the functional level of the gut microbiome.

Humans↗

KG-Microbe: Building modular and scalable knowledge graphs for microbiome and microbial sciences.

BACKGROUND: The integration of many disparate forms of data is essential for understanding the microbial world and its interaction with the environment and human health. Doing so is particularly challenging in the context of microbe-host and microbe-microbe interactions that contribute to health or environmental outcomes. There are thousands of relevant microbial species, and millions of interactions among those microbes and with their environment or host. Integrated information (e.g., about host and microbial physiology, genetics, and metabolism) facilitates deeper understanding of complex mechanisms and helps interpret correlative results. RESULTS: The KG-Microbe construction framework is a novel approach to harmonizing bacterial and archaeal data in the form of a findable, accessible, interoperable, reusable and AI-ready knowledge graph (KG). Starting from a core KG with organismal traits, environments, and growth preferences and the integration of established ontologies, the framework generates a hierarchy of related KGs targeting specific use cases, including the human microbiome in the context of disease, or environmental microbiomes. The framework supports customizable taxa subsets representing communities or clades of interest. Evaluations of the KG-Microbe KGs through a series of competency questions demonstrate the accuracy and effectiveness of the data harmonization, and the utility of the resulting KGs in studies of inflammatory bowel disease and Parkinson's disease. Finally, the predictive and environmental capabilities of the KGs are demonstrated by predicting growth preferences using graph features. CONCLUSIONS: The KG-Microbe framework unifies microbial contexts in a single resource to support integrative analyses across biomedical, host, and environmental domains. KG-Microbe is a flexible, modular enabling technology for humans and machine learning methods to uncover candidate mechanistic explanations of microbial associations.

Microbiota↗

Detection of opportunistic bacterial pathogens with intrinsic amoxicillin- and cephalosporin-resistance in wild koala faecal microbiomes.

Opportunistic bacterial pathogens frequently associated with human clinical infections, including antimicrobial-resistant strains, are infiltrating the microbiomes of wild animals, where they have the potential to negatively impact wildlife health. Bacterial genes conferring resistance to amoxicillin have previously been reported in koala (Phascolarctos cinereus) faecal DNA. Koalas are facing several key threats, including wildfires, and affected individuals may receive amoxicillin therapy to treat burn wounds. This study aimed to identify the species of amoxicillin-resistant bacteria in koala gut microbiomes and determine if they are opportunistic pathogens. Faecal samples collected from 98 wild-caught koalas were cultured using amoxicillin-supplemented media to isolate amoxicillin-resistant Gram-negative enteric bacteria. Isolates were screened using 16S rRNA PCR and Sanger sequencing to identify opportunistic pathogenic species, which then underwent whole-genome sequencing and antimicrobial susceptibility testing. Intrinsically amoxicillin-resistant opportunistic pathogens were obtained from 9.2% (9/98) of koala faecal samples and comprised Klebsiella oxytoca (6/98, 6.1%), Klebsiella pneumoniae (1/98, 1.0%) and Citrobacter spp. (2/98, 2.0%). Seven of nine amoxicillin-resistant opportunistic pathogens also exhibited cephalosporin resistance. Four K. oxytoca isolates belonged to lineages associated with human clinical infections, which also have the potential to cause disease in koalas, including fatal systemic infections in pouch young. The presence of amoxicillin- and cephalosporin-resistant strains may also increase the risk of gut dysbiosis and opportunistic infections when penicillins or cephalosporins are required to treat bacterial infections in koalas, highlighting the importance of good antimicrobial stewardship. The study findings demonstrate the One Health perspective of microbial pathogens and the intertwined microbial ecology between humans and wildlife.

Animals↗

Immunosuppressants Rewire the Gut Microbiome-Alloimmune Axis Through Time-Dependent and Tissue-Specific Mechanisms.

BACKGROUND: Lifelong immunosuppressive therapy is required to prevent allograft rejection in organ transplantation. Current immunosuppressants effectively suppress adaptive and innate immune responses, but their broad, antigen-non-specific effects often result in severe off-target complications. It remains a significant unmet medical need in transplant medicine. RESULTS: In this study we investigated immunosuppressant effects of four major immunosuppressant classes, including tacrolimus, prednisone, mycophenolate mofetil (MMF), and fingolimod (FTY), on the gut microbiome, metabolic pathways, lymphoid architecture and lymphocyte trafficking after up to 30-day chronic exposure. Despite their distinct mechanisms of action and not designed to target the gut, all immunosuppressive drugs induced profound and time-dependent alterations in both intestine gene expression and gut microbiome composition. Progressive alterations from moderate early, drug-specific changes to a strikingly convergent microbial dysbiosis, marked by significant expansion of pathobionts of Muribaculaceae, occurred across all drug classes. Concurrently, all drugs uniformly induced significant suppression of mucosal immunity including B cell, immunoglobulin, and antigen recognition. Time-dependent changes in lymph node (LN) reorganization and cellular composition were also observed, marked by a progressive shift toward pro-inflammatory phenotypes in gut-draining mesenteric LNs and a gradual loss of tolerogenic architecture in peripheral LNs. Drug-specific metabolic alterations and distinct phases of intestinal transcriptional responses were also characterized. Notably, MMF and FTY demonstrated the most robust immunomodulatory properties, and were able to suppress alloantigen-induced inflammation through mediating regulatory T cell distribution and LN remodeling. CONCLUSIONS: Together, these findings highlight the underappreciated complexity and temporal dynamics immunosuppressants effects, particularly their impact on the gut and compartmentalized regulation of alloimmune in lymphoid tissues. Understanding these relationships offers new opportunities for refining immunosuppressive strategies to reduce treatment-related off-target complications and improve long-term organ transplant outcomes.

gut dysbiosis↗

Uncertainty Modeling Outperforms Machine Learning for Microbiome Data Analysis.

Microbiome sequencing measures relative rather than absolute abundances, providing no direct information about total microbial load. Normalization methods attempt to compensate, but rely on strong, often untestable assumptions that can bias inference. Experimental measurements of load (e.g., qPCR, flow cytometry) offer a solution, but remain costly and uncommon. A recent high-profile study proposed that machine learning could bypass this limitation by predicting microbial load from sequencing data alone. To evaluate this claim, we assembled mutt, the largest public database of paired sequencing and load measurements, spanning 35 studies and over 15,000 samples. Using mutt, we show that published machine learning models fail to generalize: on average they perform worse than a naive baseline that always predicted the training set mean. These failures stem from covariate shift-limited shared taxa between studies, differences in community composition, and differences in preprocessing pipelines-that silently derail model inputs. In contrast, Bayesian partially identified models do not attempt to impute microbial load, but instead propagate scale uncertainty through downstream analyses. Across 30 benchmark datasets, Bayesian partially identified models consistently outperformed normalization and machine learning approaches, providing a principled and reproducible foundation for microbiome inference.

16S rRNA-seq↗

Association Between the Root Canal Microbiome and Apical Lesion Size: An Observational Shotgun Metagenomic Study.

AIM: The aim was to characterize the taxonomic and functional composition of the microbiome involved in primary endodontic infections and to evaluate their association with the periapical lesion size using shotgun metagenomic sequencing. METHODOLOGY: Samples from primary root canal infections diagnosed with apical periodontitis were analysed with shotgun sequencing. Samples were classified according to the lesion size as small (<&#x2009;3&#x2009;mm) or large (>&#x2009;7&#x2009;mm). The bacterial DNA copies in each group were quantified by qPCR. Taxonomic and functional annotations were made using Bracken/Kraken2 and HUMAnN3 software. Species richness, Shannon, Simpson and Pielou indices were used to measure alpha diversity. The similarity of the bacterial communities between study groups was evaluated by Principal Coordinate Analysis based on Bray-Curtis distances. The ALDEx2 package was used to infer the differences between species, and the edgeR package for KEGG pathways. For all statistical analyses, p&#x2009;<&#x2009;0.05 was considered as significant. RESULTS: A total of 49 samples were analysed, 27 with small lesions and 22 with large lesions. Species richness and Shannon indices showed differences between both groups, whereas no differences were seen according to Simpson and Pielou indices. A different community composition (PERMANOVA, p&#x2009;=&#x2009;0.0019) was observed between the two groups. Three species were significantly enriched in the large lesion samples, Filifactor alocis, Lachnospiraceae bacterium oral taxon 500 and Olsenella uli, while three others were enriched in small lesion samples, Acinetobacter baumannii, Acinetobacter pittii and Cutibacterium acnes. Functionally, benzoate, flavonoid and steroid degradation, the sphingolipid signalling pathway and proteasome function were enriched in samples with large lesions. Monoterpenoid biosynthesis, phospholipase D signalling, the sulphur relay system and staurosporine biosynthesis were enriched in small lesions. CONCLUSIONS: Teeth with large periapical lesions harbour greater bacterial loads and exhibit a more diverse microbial community than those with small lesions. Differences in species-level taxonomic composition were observed between both groups. Functionally, large lesions are enriched in pathways associated with immune evasion and pro-inflammatory activity, whereas small lesions are characterized by pathways related to apoptosis, metabolic adaptation and anti-inflammatory processes. These findings suggest that lesion severity is also shaped by the functional potential of the microbiome to modulate host inflammation.

Humans↗

VISTA: a classifier for metagenomic subspecies and community state typing of the vaginal microbiome.

Metagenomic community state types (mgCSTs) capture within-species genetic and functional diversity and community structure of the vaginal microbiome, enabling precise links between microbiome composition, function, and health-related risk. VISTA, the Vaginal Inference of Subspecies and Typing Algorithm, is a two-step classifier that assigns mgCSTs to vaginal metagenomes, providing standardized, scalable classifications.

bioinformatics↗