Sickle cell disease (SCD) is a chronic, inherited condition rising across the globe. Prior studies revealed a direct link between the gut microbiome and disease micropathology via aged-like (ANs) neutrophils in mouse models. In SCD patients community-level shifts in the gut microbiome included decreases in diversity and the Firmicutes/Bacteroidetes (F:B) ratio, coupled to a loss of short chain fatty acid producing microbes and a shift to non-canonical butyrate production and aerobic fatty acid oxidation pathways. ANs and the proviral microbiome associate with multiple blood cytokines, while bacterial gut microbiome features largely do not. Prophages depleted of genes related to lysis, transcriptional regulation, and host takeover were enriched in SCD patient guts, pointing to domestication of these elements, and 25% of prophages were shared at high identity between study patients. In sum, we identify prophage associated immune signatures and taxonomic and functional alterations to the gut microbiome that associate with SCD pathophysiology in a heterogeneous chronic disease both affected by and affecting microbiome composition and function.

The diversity of microbes reflects how cells adapt, interact and evolve across diverse environmental contexts and represents an unparalleled resource for training biological AI models. This microbial diversity can support models that go beyond sequence to capture and design biological function across systems.

Background Women with human immunodeficiency virus (HIV, WWH) experience early onset menopause and symptoms may impact antiretroviral therapy (ART) adherence. Vaginal estradiol is safe and effective for treatment of the genitourinary syndrome of menopause (GSM) but has not been studied in WWH. The study objective was to test whether vaginal estradiol would improve GSM symptoms in menopausal WWH. Methods Menopausal WWH were randomized 1:1 to 12 weeks of open-label vaginal estradiol (n = 25) versus no treatment (n = 26). Participants had at least 1 GSM vulvovaginal symptom in the month prior (dryness, itching, irritation, soreness, or dyspareunia) and clinical atrophy. The primary outcome was difference in mean symptom severity (scale 0-3) defined by the composite vaginal symptom index (VSI) between baseline and week 12. Changes in severity of participants' most bothersome symptom (MBS), vaginal maturation index (VMI), vaginal microbiome, and mucosal immune mediators were assessed. Results were compared by paired t test or Wilcoxon signed rank tests; a mixed effect model examined differences in VSI improvement between groups. Results Mean age was 59 years, 78% self-reported as Black, and all were on ART. Both groups had significant reductions in VSI, however the magnitude was significantly greater in the estradiol group (P < .0001). Estradiol and younger age were associated with VSI improvement. VMI and MBS improved significantly only in the estradiol group. There were no significant changes in the microbiome or mucosal mediators. Conclusions The favorable response to estradiol suggests that treatment perhaps initiated earlier may be beneficial for GSM in WWH and should be studied in larger clinical trials.

Sickle cell disease (SCD) is a chronic, inherited condition rising across the globe. Prior studies revealed a direct link between the gut microbiome and disease micropathology via aged-like (ANs) neutrophils in mouse models. In SCD patients community-level shifts in the gut microbiome included decreases in diversity and the Firmicutes/Bacteroides (F:B) ratio, coupled to a loss of short chain fatty acid producing microbes and a shift to non-canonical butyrate production and aerobic fatty acid oxidation pathways. ANs and the proviral microbiome associate with multiple blood cytokines, while bacterial gut microbiome features largely do not. Prophages depleted of genes related to lysis, transcriptional regulation, and host takeover were enriched in SCD patient guts, pointing to domestication of these elements, and 25% of prophages were shared at high identity between study patients. In sum, we identify a viral-immune axis in SCD pathophysiology and targetable functional alterations to the gut microbiome in a heterogeneous chronic disease both affected by and effecting microbiome composition and function.

The Microbial Dark Matter Symposium held on August 28-29, 2025, in Laguna Beach, Orange County, CA, convened a multidisciplinary group of scientists to address the vast unknowns in microbial life-from uncultured taxa and uncharacterized proteins to elusive viruses and spacefaring microbes. Set against a scenic coastal backdrop, the symposium highlighted advances in single-cell genomics, proximity ligation sequencing, and artificial intelligence-ready bioinformatics, while also probing the limits of microbial persistence, metabolism, and ecological distribution. Sessions explored microbial dark matter from multiple dimensions: cultivability, where new strategies are enabling recovery of elusive microbes; functional ambiguity, where metagenomic dark zones are illuminated by computational annotation; and genomic representation, where single-cell methods bridge gaps left by shotgun community sequencing. Researchers shared breakthroughs in identifying atmospheric microbiomes, "dark oxygen" production in groundwater ecosystems, and microbial survival on the International Space Station. The symposium emphasized integration of methods, disciplines, and ecosystems, advancing a collective push to illuminate the microbial dark matter on Earth and beyond. By highlighting emerging tools, pressing questions, and cross-domain insights, the symposium underscored the need for collaborative, open, and adaptive approaches to study the microbial unknown. The meeting marks a pivotal moment in microbiology, where cultivating knowledge of the uncultivated promises transformative understanding of life, everywhere.

Fusobacterium nucleatum (Fn) is an oral commensal inhabiting the human gingival plaque that is rarely found in the gut. However, in colorectal cancer (CRC), Fn can be isolated from stool samples and detected in metagenomes. We hypothesized that ecological characteristics of the gut are altered by disease, enabling Fn to colonize. Multiple genomically distinct populations of Fn exist, but their ecological preferences are unstudied. We identified six well-separated populations in 133 Fn genomes and used simulated metagenomes to demonstrate sensitive detection of populations in human oral and gut metagenomes. In 9,560 samples from 11 studies, Fn population C2 animalis is elevated in gut metagenomes from CRC and Crohn's disease patients and is observed more frequently in CRC stool samples than in the gingiva. Polymorphum, the most prevalent gingival Fn population, is significantly increased in Crohn's stool samples; this effect was significantly stronger in male hosts than in female. We find polymorphum genomes are enriched for biosynthetic gene clusters and fluoride exporters, while C2 animalis are high in iron transporters. Fn populations thus associate with specific clinical and demographic phenotypes and harbor distinct functional features. Ecological differences in closely related groups of bacteria inform microbiome impacts on human health. IMPORTANCE:Fusobacterium nucleatum is a bacterium normally found in the gingiva. F. nucleatum generally does not colonize the healthy gut, but is observed in approximately a third of colorectal cancer (CRC) patient guts. F. nucleatum's presence in the gut during CRC has been linked to worse prognosis and increased tumor proliferation. Here, we describe the population structure of F. nucleatum in oral and gut microbiomes. We report substantial diversity in gene carriage among six distinct populations of F. nucleatum and identify population disease and body-site preferences. We find the C2 animalis population is more common in the CRC gut than in the gingiva and is enriched for iron transporters, which support gut colonization in known pathogens. We find that C2 animalis is also enriched in Crohn's disease and type 2 diabetes, suggesting ecological commonalities between the three diseases. Our work shows that closely related bacteria can have different associations with human physiology.

Background & Aims:Western-style diets, characterized by higher fat and protein, and low micronutrient levels, promote the development of colorectal cancer (CRC). Here, we investigate the role of a Western diet on microbiome composition, sulfide production, and intestinal epithelial damage in pre-CRC mice, and validate taxonomic changes in a meta-analysis of human CRC patients. Methods:NWD1 is a purified Western-style diet that produces sporadic intestinal and colon tumors in wild-type C57BL/6 mice in the absence of genetic or carcinogen exposure. To determine how this diet influences cancer risk by shaping microbial composition and sulfide chemistry, mice were fed NWD1 or a purified control diet for 24 weeks. Microbiome composition, sulfide production, and intestinal stem cell mRNA expression were assessed. Observed microbiome changes were validated in a human CRC meta-analysis. Results:Fecal sulfide levels were tripled in NWD1-fed mice ( P< 0.00001 ), concurrent with increased abundance of the sulfidogenic Erysipelotrichaceae family. NWD1-fed mice had increased expression of mitochondrial sulfide oxidation genes in Lgr5 hi intestinal stem cells, demonstrating an adaptive response to elevated sulfide. In a meta-analysis of human CRC studies, we observed that Erysipelotrichaceae were associated with CRC, validating both canonical CRC microbes such as Solobacterium moorei and highlighting the potential contribution of previously unrecognized, disease-associated microbes. Conclusions:Our analyses connect the risk factors of Western diet, sulfide, and epithelial damage in a pre-cancer mouse model to microbiome changes observed in human CRC patients and suggest that microbial signatures of CRC and gut ecosystem alteration may manifest long before disease development.

BACKGROUND:Bacterial vaginosis (BV) is a major health problem associated with increased HIV risk. To explore underlying mechanisms, we assessed the cervicovaginal mucosal immune environment before and after metronidazole treatment in women with BV and healthy controls. METHODS:Women with BV diagnosed clinically by Amsel criteria were treated with oral or intravaginal metronidazole. Vaginal swabs and cervicovaginal lavage (CVL) were obtained at enrollment and approximately 2 and 4 weeks later for assessment of immune mediators, antiviral activity, and 16-second rRNA gene sequencing. Healthy controls had sampling at enrollment and 4 weeks. RESULTS:Vaginal pH, Nugent score, Shannon diversity index, and vaginal community state types differed significantly at enrollment between women with clinical BV (n = 19) and controls (n = 13, P < .001). BV cases had significantly higher CVL IL-1α and TNF-α but lower IgG at enrollment as compared with controls, which improved following treatment. Similar results were observed if participants with discordant molecular results (n = 3) were excluded. Most notably, CVL from BV cases enhanced, whereas control CVL inhibited, HIV infection of cells relative to buffer (mean ± SD, 138.4% ± 109.8% vs 30.9% ± 37.9%; P = .001). There was a transient reduction in HIV enhancement following treatment, which was not sustained. Enhancement correlated with community state types and markers of dysbiosis. Specifically, decreases in lactobacilli and increases in Prevotella, Dialister micraerophilus, and Peptoniphilus lacrimalis were associated with enhancement. CONCLUSIONS:These findings provide a potential mechanistic link that may contribute to the increased risk of HIV in association with BV, and they highlight the importance of early diagnosis and improved treatments.

Oral medications encounter gut commensal microbes that participate directly and indirectly in drug effects through metabolism, interactions with drug metabolites, or production of substrates that compete with drugs for drug-metabolizing enzymes, consequently influencing drug pharmacokinetics. The microbiota can also affect drug efficacy or toxicity by modulating the immune system; for example, variability in response to cancer immunotherapy, such as anti-PD-1 and anti-CTLA-4 therapies, is increasingly attributed to differences in gut microbial composition and function. These conditions indicate the need and opportunity to intentionally leverage the microbiome for drug effect; as such, the study of how intra- and inter-individual differences in the microbiome affect drug response has gained a definition termed pharmacomicrobiomics. While the need is clear, clinical studies evaluating pharmacomicrobiomic interactions are challenging due to microbiome variability, multiple potential confounders, no standardization of statistical and bioinformatics methods, and the reluctance of potential clinical study participants. In this review, we make the case for pharmacomicrobiomic clinical studies; for the use of modeling and simulation to provide a quantitative framework for data integration, hypothesis testing, and translational-to-late-stage clinical predictions; and the application of real-world data to support both using a within-subject comparison approach. We argue that an integrated and cohesive approach can address the large "inherent" inter-individual variability in the microbiome, attributed to factors such as age, lifestyle choices, environmental factors, chemical and biological exposures, and disease. In summary, there are many challenges to pharmacomicrobiomics research but also enormous potential to improve the development and utilization of pharmaceutical products.

Abstract The Bronx, New York, exhibited unique peaks in the number of coronavirus disease 2019 (COVID-19) cases and hospitalizations compared to national trends. To determine which features of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus might underpin this local disease epidemiology, we conducted a comprehensive analysis of the genomic epidemiology of the four dominant strains of SARS-CoV-2 (Alpha, Iota, Delta, and Omicron) responsible for COVID-19 cases in the Bronx between March 2020 and January 2023. Genomic analysis revealed similar viral fitness for Alpha and Iota variants in the Bronx despite nationwide data showing higher cases of Alpha. However, Delta and Omicron variants had increased fitness within the borough. While the transmission dynamics of most variants in the Bronx corresponded with mutational fitness-based predictions of transmissibility, the Delta variant presented as an exception. Epidemiological modeling confirms Delta’s advantages of higher transmissibility in Manhattan and Queens, but not the Bronx; wastewater analysis suggests underdetection of cases in the Bronx. The Alpha variant had slightly faster growth but a lower carrying capacity compared to Iota and Delta in all four boroughs, suggesting stronger limitations on Alpha’s growth in New York City (NYC). The founder effect of Iota varied between higher vaccinated and lower vaccinated boroughs with longer delay, shorter duration, and lower fitness of the Alpha variant in lower vaccinated boroughs. Amino acid changes in T-cell and antibody epitopes revealed Delta and Iota having larger antigenic variability and antigenic profiles distant from local previously circulating lineages compared to Alpha. In concert with transmission modeling, our data suggest that the limited spread of Alpha may be due to a lack of adaptation to immunity in NYC. Overall, our study demonstrates that localized analyses and integration of orthogonal community-level datasets can provide key insights into the mechanisms of transmission and immunity patterns associated with regional COVID-19 incidence and disease severity that may be missed when analyzing broader datasets.

The Bronx, New York, exhibited unique peaks in the number of coronavirus disease 2019 (COVID-19) cases and hospitalizations compared to national trends. To determine which features of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus might underpin this local disease epidemiology, we conducted a comprehensive analysis of the genomic epidemiology of the four dominant strains of SARS-CoV-2 (Alpha, Iota, Delta, and Omicron) responsible for COVID-19 cases in the Bronx between March 2020 and January 2023. Genomic analysis revealed similar viral fitness for Alpha and Iota variants in the Bronx despite nationwide data showing higher cases of Alpha. However, Delta and Omicron variants had increased fitness within the borough. While the transmission dynamics of most variants in the Bronx corresponded with mutational fitness-based predictions of transmissibility, the Delta variant presented as an exception. Epidemiological modeling confirms Delta's advantages of higher transmissibility in Manhattan and Queens, but not the Bronx; wastewater analysis suggests underdetection of cases in the Bronx. The Alpha variant had slightly faster growth but a lower carrying capacity compared to Iota and Delta in all four boroughs, suggesting stronger limitations on Alpha's growth in New York City (NYC). The founder effect of Iota varied between higher vaccinated and lower vaccinated boroughs with longer delay, shorter duration, and lower fitness of the Alpha variant in lower vaccinated boroughs. Amino acid changes in T-cell and antibody epitopes revealed Delta and Iota having larger antigenic variability and antigenic profiles distant from local previously circulating lineages compared to Alpha. In concert with transmission modeling, our data suggest that the limited spread of Alpha may be due to a lack of adaptation to immunity in NYC. Overall, our study demonstrates that localized analyses and integration of orthogonal community-level datasets can provide key insights into the mechanisms of transmission and immunity patterns associated with regional COVID-19 incidence and disease severity that may be missed when analyzing broader datasets.

Abstract A decade ago, studies in human populations first revealed the existence of a unique microbial community in the breast, a tissue historically viewed as sterile, with microbial origins seeded through the nipple and/or translocation from other body sites. Since then, research efforts have been made to characterize the microbiome in healthy and cancerous breast tissues. The purpose of this review is to summarize the current evidence for the association of the breast microbiome with breast cancer risk and progression. Briefly, while many studies have examined the breast microbiome in patients with breast cancer, and compared it with the microbiome of benign breast disease tissue or normal breast tissue, these studies have varied widely in their sample sizes, methods, and quality of evidence. Thus, while several large and rigorous cross-sectional studies have provided key evidence of an altered microbiome in breast tumors compared with normal adjacent and healthy control tissue, there are few consistent patterns of perturbed microbial taxa. In addition, only one large prospective study has provided evidence of a relationship between the breast tumor microbiota and cancer prognosis. Future research studies featuring large, well-characterized cohorts with prospective follow-up for breast cancer incidence, progression, and response to treatment are warranted.

Viral sequences are poorly annotated in environmental samples, a major roadblock to understanding how viruses influence microbial community structure. Current annotation approaches rely on alignment-based sequence ho-mology methods, which are limited by available viral sequences and sequence divergence in viral proteins. Here, we show that protein language model representations capture viral protein function beyond the limits of remote sequence homology by targeting two axes of viral sequence annotation: systematic labeling of protein families and function identification for biologic discovery. Protein language model representations capture protein functional properties specific to viruses and expand the annotated fraction of ocean virome viral protein sequences by 37%. Among unannotated viral protein families, we identify a novel DNA editing protein family that defines a new mobile element in marine picocyanobacteria. Protein language models thus significantly enhance remote homology detection of viral proteins and can be utilized to enable new biological discovery across diverse functional categories.

Summary of findings of the reviewed studies at the family taxonomic level.

Viruses of bacteria, "phages," are fundamental, poorly understood components of microbial community structure and function. Additionally, their dependence on hosts for replication positions phages as unique sensors of ecosystem features and environmental pressures. High-throughput sequencing approaches have begun to give us access to the diversity and range of phage populations in complex microbial community samples, and metagenomics is currently the primary tool with which we study phage populations. The study of phages by metagenomic sequencing, however, is fundamentally limited by viral diversity, which results in the vast majority of viral genomes and metagenome-annotated genomes lacking annotation. To harness bacteriophages for applications in human and environmental health and disease, we need new methods to organize and annotate viral sequence diversity. We recently demonstrated that methods that leverage self-supervised representation learning can supplement statistical sequence representations for remote viral protein homology detection in the ocean virome and propose that consideration of the functional content of viral sequences allows for the identification of similarity in otherwise sequence-diverse viruses and viral-like elements for biological discovery. In this review, we describe the potential and pitfalls of large language models for viral annotation. We describe the need for new approaches to annotate viral sequences in metagenomes, the fundamentals of what protein language models are and how one can use them for sequence annotation, the strengths and weaknesses of these models, and future directions toward developing better models for viral annotation more broadly.

Tartrazine (E102, FD&C Yellow 5) is a vibrant yellow azo dye added to many processed foods. The safety of this ubiquitous chemical has not been fully elucidated, and it has been linked to allergic reactions and ADHD in some individuals. In our study, bacterial species isolated from human stool decolourised tartrazine and, upon exposure to air, a purple compound formed. Tartrazine is known to undergo reduction in the gut to sulfanilic acid and 4-amino-3-carboxy-5-hydroxy-1-(4-sulfophenyl)pyrazole (SCAP). These metabolites and their derivatives are relevant to the toxicology of tartrazine. The toxicity of sulfanilic acid has been studied before, but the oxidative instability of SCAP has previously prevented full characterisation. We have verified the chemical identity of SCAP and confirmed that the purple-coloured oxidation derivative is 4-(3-carboxy-5-hydroxy-1-(4-sulfophenyl)-1H-pyrazol-4-yl)imino-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazole-3-carboxylic acid (purpurazoic acid, PPA), as proposed by Westöö in 1965. A yellow derivative of SCAP is proposed to be the hydrolysed oxidation product, 4,5-dioxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazole-3-carboxylic acid. SCAP and PPA are moderately toxic to human cells (IC50 89 and 78 μM against HEK-293, respectively), but had no apparent effect on Escherichia coli and Bacillus subtilis bacteria. These results prompt further analyses of the toxicology of tartrazine and its derivatives.

Sickle cell disease (SCD) is an inherited disorder resulting from a β-globin gene mutation, and SCD patients experience erythrocyte sickling, vaso-occlusive episodes (VOE), and progressive organ damage. Chronic hemolysis, inflammation, and repeated red blood cell transfusions in SCD can disrupt iron homeostasis. Patients who receive multiple blood transfusions develop iron overload, and another subpopulation of SCD patients manifest iron deficiency. To elucidate connections between dietary iron, the microbiome, and SCD pathogenesis, we treated SCD mice with an iron-restricted diet (IRD). IRD treatment reduced iron availability and hemolysis, decreased acute VOE, and ameliorated chronic organ damage in SCD mice. Our results extend previous studies indicating that the gut microbiota regulate disease in SCD mice. IRD alters microbiota load and improves gut integrity, together preventing crosstalk between the gut microbiome and inflammatory factors such as aged neutrophils, dampening VOE, and organ damage. These findings provide strong evidence for the therapeutic potential of manipulating iron homeostasis and the gut microbiome to ameliorate SCD pathophysiology. Many treatments, which are under development, focus on lowering the systemic iron concentration to relieve disease complications, and our data suggest that iron-induced changes in microbiota load and gut integrity are related- and novel-therapeutic targets.

Helicobacter pylori is found in the gut lining of more than half of the world's population, causes gastric ulcers, and contributes to stomach cancers. Menaquinone synthesis in H. pylori relies on the rare futalosine pathway, where H. pylori 5'-methylthioadenosine nucleosidase (MTAN) is proposed to play an essential role. Transition state analogues of MTAN, including BuT-DADMe-ImmA (BTDIA) and MeT-DADMe-ImmA (MTDIA), exhibit bacteriostatic action against numerous diverse clinical isolates of H. pylori with minimum inhibitory concentrations (MIC's) of <2 ng/mL. Three H. pylori BTDIA-resistant clones were selected under increasing BTDIA pressure. Whole genome sequencing showed no mutations in MTAN. Instead, resistant clones had mutations in metK, methionine adenosyltransferase (MAT), feoA, a regulator of the iron transport system, and flhF, a flagellar synthesis regulator. The mutation in metK causes expression of a MAT with increased catalytic activity, leading to elevated cellular S-adenosylmethionine. Metabolite analysis and the mutations associated with resistance suggest multiple inputs associated with BTDIA resistance. Human gut microbiome exposed to MTDIA revealed no growth inhibition under aerobic or anaerobic conditions. Transition state analogues of H. pylori MTAN have potential as agents for treating H. pylori infection without disruption of the human gut microbiome or inducing resistance in the MTAN target.