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Unveiling novel antimicrobial peptides from the ruminant gastrointestinal microbiomes: A deep learning-driven approach yields an anti-MRSA candidate.

INTRODUCTION: Antimicrobial peptides (AMPs) present a promising avenue to combat the growing threat of antibiotic resistance. The ruminant gastrointestinal microbiome serves as a unique ecosystem that offers untapped potential for AMP discovery. OBJECTIVES: The aims of this study are to develop an effective methodology for the identification of novel AMPs from ruminant gastrointestinal microbiomes, followed by evaluating their antimicrobial efficacy and elucidating the mechanisms underlying their activity. METHODS: We developed a deep learning-based model to identify AMP candidates from a dataset comprising 120 metagenomes and 10,373 metagenome-assembled genomes derived from the ruminant gastrointestinal tract. Both in vivo and in vitro experiments were performed to examine and validate the antimicrobial activities of the AMP candidates that were selected through bioinformatic analysis and subsequently synthesized chemically. Additionally, molecular dynamics simulations were conducted to explore the action mechanism of the most potent AMP candidate. RESULTS: The deep learning model identified 27,192 potential secretory AMP candidates. Following bioinformatic analysis, 39 candidates were synthesized and tested. Remarkably, all synthesized peptides demonstrated antimicrobial activity against Staphylococcus aureus, with 79.5% showing effectiveness against multiple pathogens. Notably, Peptide 4, which exhibited the highest antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA), confirmed this effect in a mouse model with wound infection, exhibiting a low propensity for resistance development and minimal cytotoxicity and hemolysis towards mammalian cells. Molecular dynamics simulations provided insights into the mechanism of Peptide 4, primarily its ability to disrupt bacterial cell membranes, leading to cell death. CONCLUSION: This study highlights the power of combining deep learning with microbiome research to uncover novel therapeutic candidates, paving the way for the development of next-generation antimicrobials like Peptide 4 to combat the growing threat of MRSA would infections. It also underscores the value of utilizing ruminant microbial resources.

Animals

Diet change reveals asymmetric response in gene expression and microbial composition across the digestive tract of two closely related herbivores.

BACKGROUND: Understanding what shapes variation in organisms' capacity to utilize novel resources is essential to predicting how species will respond to environmental change. For herbivores, exposure to toxic phytochemicals in novel plants may limit persistence in new habitats. We investigated the behavioral, physiological, genetic, and microbial consequences of diet switching in two closely related species of rodent herbivores that each consume differentially toxic plants in their native habitat, and that maintain different dietary strategies (i.e., relative dietary specialist versus relative generalist). RESULTS: In reciprocal laboratory feeding trials, we exposed wild-caught woodrats (genus Neotoma) to toxins characteristic of either familiar or novel plant secondary compounds. We measured changes in food and water intake, locomotor activity, gut microbial composition, and gene expression across the digestive tract following feeding trials. The dietary generalist responded minimally, but the specialist responded strongly when exposed to the novel diet. This response included behavioral and genetic components including increased water intake, reduction in locomotor activity, increased differential expression of detoxification genes, and a greater shift in gut microbial composition. CONCLUSIONS: The dietary specialist exhibited a strong response to diet switching that corresponded with ecologically relevant shifts in behavior and physiology that would have negative fitness consequences. Although the dietary specialist had a strong genetic and microbial response to novel plant secondary compounds, this response would likely be insufficient to overcome the immediate challenge of exposure to novel dietary toxins in the wild. Our results underscore the link between feeding strategy and the capacity to shift to novel dietary resources in response to environmental change.

Animals

Clostridium scindens: history and current outlook for a keystone species in the mammalian gut involved in bile acid and steroid metabolism.

Clostridium scindens is a keystone bacterial species in the mammalian gut that, while low in abundance, has a significant impact on bile acid and steroid metabolism. Numerous studies indicate that the two most studied strains of C. scindens (i.e. ATCC 35704 and VPI 12708) are important for a myriad of physiological processes in the host. We focus on both historical and current microbiological and molecular biology work on the Hylemon-Björkhem pathway and the steroid-17,20-desmolase pathway that were first discovered in C. scindens. Our most recent analysis now calls into question whether strains currently defined as C. scindens represent two separate taxonomic groups. Future directions include developing genetic tools to further explore the physiological role of bile acid and steroid metabolism by strains of C. scindens and the causal role of these pathways in host physiology and disease.

Bile Acids and Salts

Metagenomic characterization of oral microbiome signatures to predict upper gastrointestinal and pancreaticobiliary cancers: a case-control study.

BACKGROUND: This study investigated the oral microbiome signatures associated with upper gastrointestinal (GI) and pancreaticobiliary cancers. METHODS: Saliva samples from cancer patients and age- and sex-matched healthy controls were analyzed using 16S rRNA-targeted sequencing, followed by comprehensive bioinformatics analysis. RESULTS: Significant dissimilarities in microbial composition were observed between cancer patients and controls across esophageal cancer (EC), gastric cancer (GC), biliary tract cancer (BC), and pancreatic cancer (PC) groups (R2 = 0.067, = 0.075, = 0.068, and = 0.044; p = 0.001, = 0.001, = 0.002, and = 0.004, respectively). Additionally, the oral microbiome composition significantly differed by the four cancer sites (p = 0.001 for EC vs. GC, EC vs. BC, EC vs. PC, GC vs. BC, and GC vs. PC; p = 0.013 for BC vs. PC). We built oral metagenomic classifiers to predict cancer and selected specific microbial taxa with diagnostic properties. For EC, the classifier differentiated cancer patients and controls with good accuracy (area under the curve [AUC] = 0.791) and included three genera: Akkermansia, Escherichia-Shigella, and Subdoligranulum. For GC, the classifier exhibited high discriminative power (AUC = 0.961); it included five genera (Escherichia-Shigella, Gemella, Holdemanella, Actinomyces, and Stomatobaculum) and three species (Eubacterium sp. oral clone EI074, Ruminococcus sp. Marseille-P328, and Leptotrichia wadei F0279). However, microbial taxa with diagnostic features for BC and PC were not identified. CONCLUSIONS: These findings suggested that the oral microbiome composition may serve as an indicator of tumorigenesis in upper GI and pancreaticobiliary cancers. The development of oral metagenomic classifiers for EC and GC demonstrates the potential value of microbial biomarkers in cancer screening.

Humans

High dietary fiber is associated with improved outcomes in patients with melanoma and sarcoma treated with immunotherapy regardless of gut microbiome dysbiosis and social vulnerability.

BACKGROUND: Social vulnerability, dietary fiber, and the gut microbiome have been individually implicated in clinical outcomes for melanoma and sarcoma patients. This study hypothesized that increasing social vulnerability is associated with insufficient dietary fiber intake and negatively associated with microbiome composition and clinical outcomes. METHODS: Clinicopathologic data, baseline fiber intake, and gut microbiome profiles were assessed in 153 patients with melanoma or sarcoma treated with immune checkpoint blockade (ICB) and prospectively followed. Patients' social vulnerability index (SVI) and fiber intake were evaluated for associations with microbiome composition, treatment response, and overall survival (OS). RESULTS: SVI percentile was 0.4 (interquartile ratio [IQR], 0.2-0.7), and median dietary fiber intake was 17 (IQR, 15-20) g/day. SVI was inversely correlated with dietary fiber intake (r, -0.18, p&#xa0;=&#xa0;.0398). Gut microbiome analyses revealed community and compositional differences by SVI, including inverse associations with &#x3b1;-diversity and the relative abundance of favorable bacteria such as Bifidobacterium longum (p&#xa0;<&#xa0;.001), contrasting the positive associations observed between fiber and these microbial markers. Increased dietary fiber intake was associated with measurable response to ICB. A difference in OS was not observed in more socially vulnerable patients (SVI, not reached vs. 81.7 months), however, a survival advantage was evident with higher dietary fiber intake (not reached, 58.9 months). CONCLUSIONS: Increased social vulnerability was associated with a less favorable gut microbiome composition but not worse OS among melanoma and sarcoma patients treated with ICB. Consistent with prior findings, high dietary fiber intake emerged as a potentially modifiable pathway to improve outcomes in patients initiating ICB, particularly those with increased SVI.

Humans

The Gfr Uptake System Provides a Context-Dependent Fitness Advantage to Salmonella Typhimurium SL1344 During the Initial Gut Colonization Phase.

Salmonella enterica serovar Typhimurium (S. Tm) is a major cause of foodborne diarrhea. However, in healthy individuals, the microbiota typically restricts the growth of incoming pathogens, a protective mechanism termed colonization resistance (CR). To circumvent CR, Salmonella strains can utilize private nutrients that remain untapped by the resident microbiota. However, the metabolic pathways and environmental niches promoting pathogen growth are still not completely understood. Here, we investigate the significance of the gfr operon in gut colonization of S. Tm, which is essential for the utilization of fructoselysine (FL) and glucoselysine (GL). These Amadori compounds are present in heated foods with high protein and carbohydrate contents. We detected FL in both mouse chow and the intestinal tract of mice and showed that gfr mutants are attenuated during the initial phase of colonization in the murine model. Experiments in gnotobiotic mice and competition experiments with Escherichia coli suggest that gfr-dependent fitness advantage is context-dependent. We conclude that dietary Amadori products like FL can support S. Tm gut colonization, depending on the metabolic capacities of the microbiota.

Salmonella typhimurium

Contribution of the Brain-Gut-Microbiome Axis to Intergenerational Abnormalities in a Rat Model of Perioperative Neurocognitive Disorder.

BACKGROUND: The brain-gut-microbiome (BGM) axis is a communication network through which the brain and gastrointestinal microbiota interact via neural, hormonal, immune, and gene expression mechanisms. Gut microbiota dysbiosis is thought to contribute to neurocognitive disorders, including perioperative neurocognitive disorder, and to various metabolic abnormalities. Recently, the authors reported that sevoflurane induces neurocognitive deficits in exposed rats as well as their future offspring, with male offspring being particularly affected (intergenerational perioperative neurocognitive disorder). In this study, the authors examined in the same animals whether the intergenerational effects of sevoflurane involve abnormalities in the BGM axis, and whether they are mitigated by paternal pretreatment with either the Na + -K + -Cl - (NKCC1) Cl - transporter inhibitor bumetanide or the glucocorticoid receptor inhibitor RU486, as previously demonstrated for neurocognitive deficits. METHODS: Male Sprague-Dawley rats (F0 generation) were exposed to 2.1% sevoflurane for 3&#x2009;h on postnatal days 56, 58, and 60 (F0M_S group). Before each sevoflurane exposure, distinct experimental groups of F0 males received bumetanide (F0M_BS group) or RU486 (F0M_RS group). These males were mated on postnatal day 90 to produce offspring (F1 generation). Gut microbiota were profiled using 16S rRNA gene sequencing, and brain changes analyzed via RNA sequencing of hippocampal samples. RESULTS: F1 male offspring of F0M_S sires exhibited heightened corticosterone responses to stress, increased inflammatory markers, altered hippocampal transcriptomes, gut microbiota dysbiosis, elevated serum low-density lipoprotein cholesterol levels, and increased body weight. The only abnormality observed in F1 females was a shift in microbial diversity. F0M_S displayed profound alterations in hippocampal transcriptome, while microbial diversity was the only parameter affected in their gut microbiota. Bumetanide or RU486 mitigated most abnormalities, except increased body weight in F1 males. CONCLUSIONS: Paternal sevoflurane exposure in rats induces BGM axis abnormalities, particularly in male offspring, despite the absence of direct anesthetic exposure. Pretreatment with bumetanide or RU486 showed therapeutic efficacy.

Animals

Improved detection of microbiome-disease associations via population structure-aware generalized linear mixed effects models (microSLAM).

Microbiome association studies typically link host disease or other traits to summary statistics measured in metagenomics data, such as diversity or taxonomic composition. But identifying disease-associated species based on their relative abundance does not provide insight into why these microbes act as disease markers, and it overlooks cases where disease risk is related to specific strains with unique biological functions. To bridge this knowledge gap, we developed microSLAM, a mixed-effects model and an R package that performs association tests that connect host traits to the presence/absence of genes within each microbiome species, while accounting for strain genetic relatedness across hosts. Traits can be quantitative or binary (such as case/control). MicroSLAM is fit in three steps for each species. The first step estimates population structure across hosts. Step two calculates the association between population structure and the trait, enabling detection of species for which a subset of related strains confer risk. To identify specific genes whose presence/absence across diverse strains is associated with the trait, step three models the trait as a function of gene occurrence plus random effects estimated from step two. Applying microSLAM to 710 gut metagenomes from inflammatory bowel disease (IBD) samples, we discovered 56 species whose population structure correlates with IBD, meaning that different lineages are found in cases versus controls. After controlling for population structure, 20 species had genes significantly associated with IBD. Twenty-one of these genes were more common in IBD patients, while 32 genes were enriched in healthy controls, including a seven-gene operon in Faecalibacterium prausnitzii that is involved in utilization of fructoselysine from the gut environment. The vast majority of species detected by microSLAM were not significantly associated with IBD using standard relative abundance tests. These findings highlight the importance of accounting for within-species genetic variation in microbiome studies.

Humans

Maternal contact and age-dependent succession influence the assembly of the calf rumen microbiome and virome.

Early-life colonization of the rumen is particularly important; however, the processes by which microbial and viral communities are transmitted and developed remain poorly understood. Here, we present a genome-resolved investigation of the effects of maternal contact and age-dependent succession on the calf rumen microbiome and DNA virome by comparing calves raised with or without maternal contact across early life using the metagenome-assembled genomes (MAGs) and viral operational taxonomic units (vOTUs) reconstructed from whole- and virus-like particle metagenomes. Across longitudinal samples from calves and their mothers, we identified 694 MAGs and 30,479 vOTUs, substantially expanding current genome databases and revealing extensive microbial and viral novelty. Our analyses demonstrated that both prokaryotes and DNA viruses are shared between dams and calves, with greater sharing observed in calves raised with maternal contact than in calves raised without maternal contact. Notably, viral sharing between cow-calf pairs was markedly lower compared to prokaryotes, suggesting high turnover and rapid viral diversification. Age-associated analyses further revealed coordinated shifts in prokaryotes and their viruses, with dominant genera such as Prevotella, Ruminococcus, and Fibrobacter, and their corresponding viruses increasing after day 40. These findings indicate that the early-life rumen microbiome and DNA virome undergo substantial age-dependent succession and are associated with maternal contact, providing new insights into host-microbe-virus interactions during rumen development.IMPORTANCEThis study provides one of the first genome-resolved views of DNA viral community development during early rumen colonization in calves (from 1 week to 70 days of age) and reveals how maternal contact and age influence the establishment of the calf rumen microbiome and virome. By analyzing longitudinal samples from calves raised with or without their mothers, we show that prokaryotes and their viruses undergo coordinated, age-dependent succession. Our results demonstrate that maternal separation alters the assembly of the calf rumen microbiome, highlighting the influence of maternal contact during early-life rumen development. These findings underscore the high plasticity of the early-life rumen ecosystem and suggest that early management practices, such as maternal separation, can have lasting effects on rumen development. This work provides fundamental insights into the establishment and succession of the calf rumen microbiome and DNA virome during early life and may contribute to future microbiome manipulation studies.

Animals

Dealcoholized muscadine wine improved skin elasticity and oxidative stress biomarkers without affecting gut microbiome in women over 40 in a randomized controlled trial.

Muscadine wine has a unique polyphenol profile distinct from that of common wine, and limited research exists on its health benefits. This study aimed to investigate the effects of intake of dealcoholized muscadine wine (DMW) on skin health, oxidative stress, inflammatory biomarkers, and the gut microbiome. Seventeen healthy women were randomly assigned to consume 300&#xa0;mL of DMW or a placebo daily for 6&#xa0;weeks, separated by a 3-week washout period, in a randomized, single-blinded, crossover design. Skin health parameters were measured on the face and forearm. Oxidative stress and inflammatory biomarkers were assessed in plasma. Fecal bacterial DNA was sequenced using shotgun sequencing. DMW did not affect UVB-induced erythema compared to placebo. However, it significantly decreased transepidermal water loss and increased facial gross elasticity. Skin elasticity significantly improved on the forearm, whereas other skin parameters were not affected. DMW significantly decreased plasma levels of matrix metalloproteinase-9 and advanced glycation end products compared with placebo. However, the abundance, diversity, and functions of the gut microbiome were not affected. Polyphenol-rich DMW administered for six weeks improved certain skin health parameters and reduced oxidative and inflammatory stress, without affecting the gut microbiome in healthy women.

Humans

Healthy subjects gut microbiome modulation by Bacillus coagulans BCP92: A randomized, double-blind, placebo-controlled clinical trial.

BACKGROUND: Probiotics are recognized for their ability to restore balance in the gut microbiome during dysbiosis. However, their effects on the gut microbiota of healthy individuals have rarely been investigated. This study aimed to evaluate the safety and efficacy of Bacillus coagulans (Heyndrickxia coagulans) BCP92 and its influence on microbiota composition in healthy subjects. METHODS: In the present investigation, healthy participants (n&#x2005;=&#x2005;48) were allocated into 2 groups and administered either Bacillus coagulans BCP92 capsules (1 billion CFU/capsule) or a placebo containing maltodextrin for 42 days. Microbiome composition and short-chain fatty acid analyses were subsequently conducted. RESULTS: Analysis of metagenomes showed no major alterations in gut microbiome composition among participants who received B. coagulans BCP92 supplementation. However, subtle beneficial changes were observed in the treatment group, suggesting that probiotic administration may increase advantageous phyla, classes, orders, families, and some genera, while decreasing potentially harmful groups. A slight increase in short-chain fatty acids (SCFA) was also observed in the fecal samples. CONCLUSIONS: This study implies that extended supplementation with the probiotic B. coagulans BCP92 may lead to substantial improvements in gut microbiome composition and SCFA levels.

Humans

Gut microbiota: a hidden player in polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is an endocrine disorder that affects reproductive-aged women worldwide, causing hormonal imbalances and ovarian dysfunction. PCOS affects metabolic health and increases the risk of obesity, insulin resistance, and cardiovascular disease, in addition to infertility. This review delves deeper into the connections of gut microbiota with PCOS pathophysiology, particularly into its impact on hormone metabolism, obesity, inflammation, and insulin resistance by way of short-chain fatty acids, lipopolysaccharides, and gut-brain axis. Studies also show that changes in the metabolic processes and immune responses are seen in changes in the gut microbiota in PCOS subjects, such as changes in the Bacteroidetes and Firmicutes groups. Some bacteria, like Escherichia and Shigella, have been associated with dysbiosis in patients with PCOS, leading to systemic inflammation and changed hormone levels, which further worsen the clinical symptoms. Therapeutic interventions targeting the gut microbiota comprise probiotics, prebiotics, and fecal microbiota transplantation; these have potential to alleviate the symptoms of PCOS. Other precision microbiome-based therapies include postbiotics, and CRISPR-Cas9 genome editing, which are relatively new avenues toward precision treatment. This complex interlink of gut microbiota and PCOS pathophysiology will open the avenues for possible treatments for hormonal imbalances and metabolic problems that characterize these complex disorders. The review here focuses on the requirement of further studies to be able to elucidate the specific pathways relating gut microbiota dysregulation to PCOS and, thus, improve microbiome-based therapies for better clinical outcomes in affected individuals.

Humans

Synthesis and Application of a Suite of 2,5-Aryl Tetrazole Photoaffinity-Based Probes for Profiling Microbial Carbohydrate and Mucin Metabolism in Gut Microbiota.

Photoaffinity-based chemoproteomics provides a strategy for interrogating protein engagement and networks within complex biological systems. In the context of carbohydrate metabolism, however, linking the probe structure to glycan-processing networks remains challenging due to the diversity and redundancy of carbohydrate-active enzymes (CAZymes). Here, we employ 2,5-tetrazoles as photoreactive groups to develop a suite of monosaccharide-bearing probes designed to capture carbohydrate-associated protein environments in gut microorganisms. Across defined bacterial cultures and human fecal lysates, tetrazole probes enriched glycoside hydrolases (GHs) and additional carbohydrate-associated proteins, including transporters and regulatory elements. Notably, enrichment profiles were functionally biased toward glycan-processing modules, despite minimal shifts in global protein abundance under different growth conditions. These findings demonstrate that tetrazole chemoproteomics complements abundance-based proteomics by reporting on glycan-associated protein engagement and organization. Together, this probe suite provides a substrate-centric approach to studying carbohydrate-processing networks in defined microbes and complex microbiomes.

Tetrazoles

Mechanisms linking the gut microbiota to colorectal cancer development and progression.

Colorectal cancer remains a leading cause of global cancer mortality, with a concerning rise in early-onset cases driven by complex interactions between environmental exposures, lifestyle factors, and host genetics. Mounting evidence indicates that gut microbiota dysbiosis critically modulates this oncogenic process, acting as an active participant rather than a passive bystander. This review systematically synthesizes the dichotomous roles of the intestinal microbiome in colorectal tumorigenesis through the conceptual framework of the driver-passenger model. We discuss how early initiating driver bacteria, such as Polyketide synthase-positive Escherichia coli and enterotoxigenic Bacteroides fragilis, compromise mucosal barriers, induce chronic mucosal inflammation, and inflict direct genomic instability. As the local tumor microenvironment undergoes profound metabolic remodeling, opportunistic passenger pathogens, notably Fusobacterium nucleatum, become enriched, further promoting cellular proliferation and facilitating tumor immune evasion. Conversely, protective commensals, exemplified by Clostridium butyricum and Streptococcus thermophilus, exert robust tumor-suppressive effects through multifaceted mechanisms. These beneficial microbes actively antagonize malignant progression by redirecting tumor metabolic fluxes toward oxidative stress, orchestrating deep epigenetic reprogramming, and degrading core oncoproteins to reverse chemoresistance. Transitioning from fundamental mechanisms to clinical application, we evaluate a comprehensive spectrum of microbiota-targeted interventions, encompassing non-invasive diagnostic biomarkers, fecal microbiota transplantation, engineered bacteria, phage therapy, and postbiotics. Finally, we critically address the formidable translational challenges associated with microbial heterogeneity, long-term safety, and regulatory standardization, aiming to provide a balanced perspective on integrating microbiome-based strategies into next-generation precision oncology for colorectal cancer.

Humans

Intestinal microbiome profiles in broiler chickens raised without antibiotics exhibit altered microbiome dynamics relative to conventionally raised chickens.

The present study was undertaken to profile and compare the cecal microbial communities in conventionally (CONV) grown and raised without antibiotics (RWA) broiler chickens. Three hundred chickens were collected from five CONV and five RWA chicken farms on days 10, 24, and 35 of age. Microbial genomic DNA was extracted from cecal contents, and the V4-V5 hypervariable regions of the 16S rRNA gene were amplified and sequenced. Analysis of 16S rRNA sequence data indicated significant differences in the cecal microbial diversity and composition between CONV and RWA chickens on days 10, 24, and 35 days of age. On days 10 and 24, CONV chickens had higher richness and diversity of the cecal microbiome relative to RWA chickens. However, on day 35, this pattern reversed such that RWA chickens had higher richness and diversity of the cecal microbiome than the CONV groups. On days 10 and 24, the microbiomes of both CONV and RWA chickens were dominated by members of the phylum Firmicutes. On day 35, while Firmicutes remained dominant in the RWA chickens, the microbiome of CONV chickens exhibited am abundance of Bacteroidetes. The cecal microbiome of CONV chickens was enriched with the genus Faecalibacterium, Pseudoflavonifractor, unclassified Clostridium_IV, Bacteroides, Alistipes, and Butyricimonas, whereas the cecal microbiome of RWA chickens was enriched with genus Anaerofilum, Butyricicoccu, Clostridium_XlVb and unclassified Lachnospiraceae. Overall, the cecal microbiome richness, diversity, and composition were greatly influenced by the management program applied in these farms. These findings provide a foundation for further research on tailoring feed formulation or developing a consortium to modify the gut microbiome composition of RWA chickens.

Animals

The role of mobile genetic elements in adaptation of the microbiota to the dynamic human gut ecosystem.

The human intestinal microbiota is a dynamic ecosystem shaped by extensive horizontal gene transfer, particularly in individuals from industrialized populations. In this review, we discuss recent advances in our understanding of how mobile genetic elements (MGEs) contribute to microbial ecology and evolution in this diverse community, focusing on MGEs carrying fitness-conferring genes. Bacteroidales species can colonize individuals for decades and serve as major hubs for MGE exchange. Most MGEs are highly variable across individuals and geographies. Occasionally, conserved MGEs can spread across geography and lifestyles. Functional characterizations of MGEs reveal their roles in antibiotic resistance, interbacterial antagonism, biofilm formation, immune evasion, and nutrient acquisition, among others. Substantive progress in our understanding of MGEs in the gut microbiome offers promising avenues for therapeutic microbiome interventions. However, major challenges remain in functional prediction, host-MGE linkage, and experimental characterization.

Humans

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

Divergent microbial preludes to necrotising enterocolitis defined by gut phages and bacterial resistomes.

BACKGROUND: Translating microbiome correlations into robust predictive features for complex gut disorders remains elusive, partly due to oversimplified models of pathogenesis and neglect of the virome, a key player in microbial ecosystems. Necrotising enterocolitis (NEC), a devastating disease of preterm infants with no reliable clinical predictors, exemplifies this challenge. OBJECTIVE: To determine the predictive potential of the gut prophageome and polymicrobial aetiologies for NEC. DESIGN: We applied integrated metagenomic and metatranscriptomic analyses and machine learning to 1825 longitudinal stool samples from 43 preterm infants who later developed NEC and 86 gestational age-matched and birthweight-matched controls across three US hospitals. We characterised gut prophageome acquisitions and their association with clinical exposures, including antibiotics, diet and pharmacotherapies. To predict NEC risk, we integrated pre-onset prophageome, antibacterial resistome and bacteriome profiles with neonatal pathology, stratifying the cohort by disease onset timing (early: &#x2264;40 days; late: >40&#x2009;days) for separate analysis. RESULTS: NEC cases exhibited distinct viral diversity trajectories before disease onset. Early-onset NEC was best predicted by phage-bacterial interaction signatures (75% accuracy, 81% sensitivity). Metatranscriptomics revealed increased phage DNA abundance with low gene expression, suggesting a lysogenic lifestyle that may stabilise pathobionts. These phages encode metabolic genes potentially enhancing pathobiont resilience. Late-onset NEC was best predicted by antibacterial resistome profiles (83% accuracy). CONCLUSION: The gut prophageome serves as both a source of pre-symptomatic predictive signals and an active modulator of NEC pathogenesis, with distinct microbial mechanisms driving early-onset and late-onset disease. These polymicrobial etiologies inform strategies for early detection, risk stratification and the development of microbiome-targeted preventive and therapeutic interventions.

BIOMARKERS