Gut Microbiota Research Articles

Gut Microbial Signatures Associated with Cryptosporidiosis: A Case Series

Cryptosporidium spp. are zoonotic protozoan parasites with a global prevalence, with both gastrointestinal and pulmonary involvement. Though symptoms can often be relatively mild, they can become severe and even fatal in children under five, the elderly, and in immunocompromised individuals, making cryptosporidiosis a leading cause of morbidity and mortality in fragile populations. Furthermore, there is an urgent clinical need for alternative therapies against cryptosporidiosis, as currently available FDA-approved treatments are ineffective in the immunocompromised. Recent evidence in animal models suggests that the gut microbiota (GM) can influence both host and parasite biology to influence the course of Cryptosporidium infection. Here, we present GM profiles in five cases of cryptosporidiosis, associated with varying underlying pathologies. We found that moderate–severe cryptosporidiosis was characterized by a reduction in alpha-diversity and an enrichment of Enterococcus spp., while decreases in Bifidobacterium, Gemmiger, and Blautia were detectable in the milder manifestations of the disease. Our results suggest that severe cryptosporidiosis is associated with a stronger change on the GM than is age or underlying pathology. Together with previously published studies in animal models, we believe that these results suggest that the GM could be a potential therapeutic target for human patients as well, particularly in the immunocompromised for whom anti-Cryptosporidium treatment remains largely ineffective.

Stochastic processes govern gut bacterial community assembly in a Schistosoma mansoni-transmitting snail, Biomphalaria straminea.

Studies have revealed extensive taxonomic classifications and patterns of gut microbial diversity in snails, with limited focus on community assembly processes. To better understand the balance between stochastic and deterministic processes in the snail gut microbial assembly and their associations with snail fitness, we used the freshwater snail Biomphalaria straminea as a model and analyzed the gut bacterial communities from 118 samples via high-throughput sequencing of the 16S rRNA gene. This study reveals that Proteobacteria and Bacteroidota dominate the gut microbiota of B. straminea. Snails from different laboratory habitats exhibit similar gut bacterial diversity but significantly different community structures. The assembly of gut bacterial communities in both laboratory and wild samples is predominantly influenced by stochastic processes rather than deterministic processes, as evidenced by the neutral community model (NCM). Furthermore, during the snail invasion and adaptation to a new environment, stochastic processes are more crucial than deterministic ones in shaping the snail gut microbiota. This indicates that the interplay between stochastic and deterministic processes in the snail gut microbial assembly is associated with host fitness during snail adaptation to a new environment. Based on the null model analysis, we also found that stochastic processes (based on dispersal limitation, homogenizing dispersal, and undominated processes) play a larger role than deterministic (based on homogeneous selection and variable selection) in driving the snail gut bacterial community assembly. Furthermore, the significant difference in the proportions of dispersal limitation and undominated processes is linked to both adaptive and non-adaptive snails. This study demonstrates that stochastic processes govern the assembly of the gut microbiota in B. straminea. Furthermore, snail adaptation is associated with the interplay between stochastic and deterministic processes in gut microbial composition. This study provides a better understanding of the dynamic patterns of the gut microbial community in freshwater gastropods and may contribute to the development of strategies for controlling intermediate hosts and schistosomiasis.

Antimicrobial peptide AP2 ameliorates Salmonella Typhimurium infection by modulating gut microbiota

BackgroundEndogenous antimicrobial peptides and proteins are essential for shaping and maintaining a healthy gut microbiota, contributing to anti-inflammatory responses and resistance to pathogen colonization. Salmonella enterica subsp. enterica serovar Typhimurium (ST) infection is one of the most frequently reported bacterial diseases worldwide. Manipulation of the gut microbiota through exogenous antimicrobial peptides may protect against ST colonization and improve clinical outcomes.ResultsThis study demonstrated that oral administration of the antimicrobial peptide AP2 (2 µg /mouse), an optimized version of native apidaecin IB (AP IB), provided protective effects against ST infection in mice. These effects were evidenced by reduced ST-induced body weight loss and lower levels of serum inflammatory cytokines. A 16 S rRNA-based analysis of the cecal microbiota revealed that AP2 significantly modulated the gut microbiota, increasing the relative abundance of Bifidobacterium while decreasing that of Akkermansia at the genus level. Furthermore, the transplantation of fecal microbiota from AP2-treated donor mice, rather than from Control mice, significantly reduced cecal damage caused by ST and decreased the concentration of ST by one order of magnitude after infection.ConclusionsThese findings reveal a novel mechanism by which exogenous antimicrobial peptides mitigate Salmonella Typhimurium infection through the modulation of gut microbiota.

Microbiota of Punctuated Snake Eel Ophichthus remiger (Valenciennes, 1842) Reared in Recirculation System Is Dominated by Latilactobacillus

Research on microbiota has underscored the crucial influence of microbial communities on numerous biological functions that yield positive outcomes for the host, such as digestion, nutrient metabolism, resistance against pathogen invasion, and growth performance. Concurrently, numerous variables, including the host’s diet, genetics, and physiological condition and environmental factors, influence the gut microbiota. Our study aims to characterize the bacterial community composition of the common snake eel (Ophichthus remiger), captured wild and then reared under controlled conditions. We employed a 16S rRNA gene-based approach facilitated by next-generation sequencing to conduct this analysis. The gut microbiota of the snake eel was highly dominated by bacteria from the phylum Firmicutes, comprising over 80% of the relative abundance, with Lactilactobacillus being the most important genus. The results suggest that feed-associated bacteria may influence the composition of the microbiota, contributing the most relevant bacteria within the intestinal content. This study provides the first comprehensive analysis of the gut microbiota in Ophichthus remiger, offering novel insights into the potential roles of Firmicutes and Lactilactobacillus in marine eels.

Biologically Active Peptides from Corn Gluten Meal Improve Microbiota Disorders Caused by Helicobacter pylori Infection in Mice

This study investigated the potential effects of corn protein activity peptides (CPAPs) on inflammation response levels and gastrointestinal microbiota in Helicobacter pylori (H. pylori) infection mice. CPAPs significantly up-regulated the mRNA expression of the anti-inflammatory factor IL-10 and down-regulated the mRNA expression of the pro-inflammatory factors TGF-β, TLR4, MyD88, and NF-κB, indicating that CPAPs may antagonize H. pylori-induced inflammatory responses by inhibiting NF-κB signaling pathways. Through the intervention of CPAPs, H. pylori colonization in the stomach was significantly reduced. Additionally, the structural composition of the gastrointestinal microbiota improved, with an increase in abundance and diversity. These changes positively regulate gastrointestinal microbiota disorders in mice. In addition, the PICRUST function prediction of intestinal microbiota revealed that CPAPs may prevent or reduce metabolic disorders brought about by H. pylori, which improve biometabolic pathways by modulating intestinal microbiota composition. In conclusion, these findings suggest that CPAPs may prevent or mitigate metabolic disorders induced by H. pylori, offering theoretical support for the development of corn-protein-based functional foods.

Health-Improving Effects of Polyphenols on the Human Intestinal Microbiota: A Review

Dietary polyphenols are garnering attention in the scientific community due to their potential health-beneficial properties and preventative effects against chronic diseases, viz. cardiovascular diseases, diabetes, obesity, and neurodegenerative diseases. Polyphenols are antioxidants that change microbial composition by suppressing pathogenic bacteria and stimulating beneficial bacteria. The interaction of polyphenols with dietary fibers affects their bioaccessibility in the upper and lower parts of the digestive tract. Dietary fibers, polyphenols, their conjugates, and their metabolites modulate microbiome population and diversity. Consuming polyphenol-rich dietary fibers such as pomegranate, cranberry, berries, and tea improves gut health. A complex relationship exists between polyphenol-rich diets and gut microbiota for functioning in human health. In this review, we provide an overview of the interactions of dietary polyphenols, fibers, and gut microbiota, improving the understanding of the functional properties of dietary polyphenols.

ILSI Europe Systematic Review: The Impact of Digestible and Nondigestible Carbohydrate Consumption for Toddlers (1-4 Years) in Relation to Health Outcomes.

Early dietary habits play a crucial role in shaping long-term health outcomes. Understanding the effects of different carbohydrate types on physiological markers is essential for developing evidence-based nutritional guidelines for toddlers. The aim was to systematically evaluate the impact of both digestible and nondigestible carbohydrate intake during early childhood (1-4 years of age) on various health outcomes, including growth patterns, metabolic parameters, and the development of risk of cardiovascular diseases. PubMed, Embase, and CENTRAL databases were searched up to April 2022 to identify studies investigating carbohydrate consumption in toddlers. The types of carbohydrates consumed, their sources, and their associations with growth parameters and metabolic markers were extracted. Thirty-one publications, including 18 cohort studies and 2 randomized controlled trials, were included. The risk of bias was assessed using the Mixed Methods Appraisal Tool. A narrative synthesis was performed, with a visual summary table of the direction of effects. In toddlers, the negative impact on health risks later in life is more pronounced for digestible dietary carbohydrate intake in liquid forms, such as sugar-sweetened beverages and fruit juice, compared with solid forms. Higher nondigestible carbohydrate (dietary fiber) intake during early childhood showed a beneficial trend on later lipid profile. Further studies are required to comprehensively assess the effect of digestible and nondigestible carbohydrate intake in toddlers on cognitive and psychomotor development, infections, bowel function, and gut microbiota.

Helicobacter pylori CagA+ strains modulate colorectal pathology by regulating intestinal flora

AimThis article aims to investigate the role of Helicobacter Pylori (HP) CagA+ strains affected colorectal lesion via gut microbiota.Method6-week C57BL/6J mice were divided into: (a) HP CagA+ group undergoing HP CagA+ strains administration by gavage at 0.2 mL for 10 days; (b) HP CagA- group undergoing HP CagA- strains administration by gavage at 0.2 mL for 10 days; (c) control group intragastrically given 0.2 mL of brian heart infusion (BHI) medium for 10 days. Gastric mucosa was collected for Giemsa staining, and colorectal mucosa was for hematoxylin and eosin (H&E) staining, 16 S ribosomal RNA (rRNA) sequencing and immunohistochemistry for Major Histocompatibility Complex (MHC). Colon tissues and serum from caudal vein was collected for quantification of interleukin (IL)-6, IL-8, IL10 and tumor necrosis factor (TNF-α).ResultsMice with HP CagA+ infection developed loss of some resident cells and inflammation infiltration in colorectal mucosa, and increased Giemsa-positive cells in gastric tissue. Also, MHC II-positive cells were increased in colorectal tissue in HP CagA+ strains infection. HP CagA+ infection cause increase of TNF-α, IL-6, IL-8 and IL-10 in the serum. Meanwhile, HP CagA+ stainis evoked gut microbiota dysbiosis which was characterized by altered microbiome distribution, reduction in Front-to-Back (F/B ratio), decreased α-diversity metric (Chao1 and Shannon). In β-diversity, gut microbiota in control and HP CagA+ groups showed the significant distance based on UniFrac distance. Cag group was enriched a higher abundance of Staphylococcus and Corynebacterium, while control subjects were enriched in Marinifilaceae and Odoribacter.ConclusionHP CagA+ strains are capable of causing gut microbiota dysbiosis to develop destruction of intestinal barrier, and it may affect the development of colorectal cancer by increasing colonization of Staphylococcus and Corynebacterium.

Electroacupuncture alleviates functional constipation by upregulating host-derived miR-205-5p to modulate gut microbiota and tryptophan metabolism

Electroacupuncture (EA) has shown promise as a treatment for Functional constipation (FC), with growing evidence suggesting it may enhance gut motility. MicroRNAs (miRNAs) serve as key regulatory molecules mediating host-microbiota interactions. However, the specific fecal miRNAs regulating microbiota composition and metabolism in EA-treated constipated mice, along with their key targets, remain unidentified. We examined fecal microbiome composition, metabolism, and colonic miRNA expression in loperamide-induced constipated mice and EA-treated mice to identify differentially expressed miRNAs and assess their relationships with microbial abundance, metabolism, and gut motility. An antibiotic cocktail and adeno-associated virus were employed to interfere with the gut microbiota and target miRNA in vivo, thereby validating the proposed mechanism. Our results indicate that miR-205-5p, significantly upregulated in fecal and colonic tissues of EA-treated constipated mice, promotes intestinal motility in a microbiome-dependent manner. Specifically, EA promoted the growth of Lactobacillus reuteri, enriched in the feces of constipation-recovered mice, through host-derived miR-205-5p regulation. Furthermore, Lactobacillus reuteri and its tryptophan metabolites (indole-3-acetamide, indole-3-acetic acid, and indole-3-carboxaldehyde) alleviated loperamide-induced constipation. These findings underscore the pivotal role of host-derived miR-205-5p in modulating microbial composition and tryptophan metabolites to enhance intestinal motility through EA.

Gut microbiota and OMVs: Unveiling novel regulatory mechanisms in high‐altitude myocardial injury

Gut microbiota and OMVs: Unveiling novel regulatory mechanisms in high‐altitude myocardial injury

Effects of multidrug-resistant bacteria and multi-antibiotic combination on intestinal microbiota in mice

Multidrug-resistant bacteria are a clinical and an epidemiological challenge. However, the effects of multidrug-resistant bacteria and multi-antibiotic combination on gut microbiota are unclear. In this study, the effects of multidrug-resistant bacteria and multi-antibiotic combination on intestinal microbiota in mice have been observed by high-throughput sequencing. Resistant Escherichia coli (RP4) and 0.5, 1, and 2 mg/L antibiotics (Amp, Km, and Tet multi-antibiotic combination) could decrease the number of specific operational taxonomic units from 223 in the normal saline control group to 178 in the antibiotic-resistant bacteria group and 34 in the antibiotic group, and antibiotics are the biggest influencing factor. Multidrug-resistant bacteria and multi-antibiotic combination could affect the function of intestinal microbiota, and the effect of multidrug-resistant bacteria was similar to that of multi-antibiotic combination. Small intestine is the main colonization site of antibiotic-resistant bacteria, and Proteobacteria and Bacteroidetes are the major antibiotic-resistance acquired bacteria as determined by transmission electron microscopy and agarose plate screening culture.

Combined metabolomics and 16S rDNA sequence analyses of the gut microbiome reveal the action mechanism of Fructus Akebiae against hepatic fibrosis

ObjectivesTo explore the mechanism underlying the effect of Fructus Akebiae (FAE) against hepatic fibrosis in mice through combined network pharmacology, liver metabolomics, and 16S rDNA analyses of the gut microbiota.MethodsIn this study, we randomly divided mice into the control, model, FAE high-dose, FAE medium-dose, and FAE low-dose groups to analyze the pathological changes in the hepatic fibrosis and levels of the α-SMA, collagen 1, Nuclear Factor Kappa B (NF-κ B), Toll Like Receptor 4 (TLR4). The gut microbiota was analyzed through 16S rDNA sequencing analysis of liver metabolites using liquid chromatography-mass spectrometry. Furthermore, network pharmacology was used to determine the specific molecular regulation mechanism of FAE in hepatic fibrosis treatment.ResultsFAE treatment markedly improved the pathological changes in the hepatic fibrosis. Analysis revealed that FAE administration reversed the carbon tetrachloride (CCl4)-induced dysbiosis by increasing the abundance of Akkermansia and reducing that of Cyanobacteria. Additionally, metabolomic analysis showed that FAE treatment reversed the CCl4-induced metabolic disorders by regulating amino and nucleotide sugar metabolism. Furthermore, correlation analysis showed that Akkermansia and Verrucomicobiota were closely related to D-tolasaccharide and maltotetraose saccharide. Moreover, network pharmacology indicated that FAE might regulate the signaling pathway through the JUN/CASP3/NOS3/PTGS2/HSP90AA1 during treatment.ConclusionFAE may be a promising treatment for hepatic fibrosis, and its protective effects are associated with improvements in the microbiome and metabolic disorders.

The Role of Probiotics in Modulating Gut Microbiota and Metabolic Health for Weight Management: A Mini Review

The rising global prevalence of obesity and its associated metabolic disorders highlights the urgent need for innovative, sustainable interventions. Probiotics, as modulators of gut microbiota, have emerged as promising agents in weight management by influencing metabolic health. This mini-review explores the role of probiotics in modulating gut microbiota to support energy metabolism, appetite regulation, and fat storage. Evidence underscores the strain-specific benefits of probiotics, such as Lactobacillus gasseri SBT2055, Bifidobacterium breve B-3, and Akkermansia muciniphila, in reducing visceral fat, improving glucose metabolism, and mitigating obesity-related inflammation. The mechanisms underlying these effects include short-chain fatty acid (SCFA) production, modulation of appetite-regulating hormones, and improvements in gut barrier integrity. While the findings are promising, variability in outcomes highlights the importance of tailored probiotic interventions and underscores the need for standardized methodologies in future research. By addressing these challenges, probiotics can serve as integral components of personalized nutrition strategies, advancing both metabolic health and public health objectives.

Optimization of the cholesterol gallstone model in C57BL/6 mice and evaluation of Lactobacillus intervention effects

Gallstone disease is a common and complex condition, strongly associated with abnormal cholesterol metabolism, changes in bile composition, and impaired gallbladder motility. Recent studies have suggested that the gut microbiota, particularly probiotics like lactic acid bacteria, may play a significant role in the prevention and treatment of cholesterol gallstones. This study aims to optimize the cholesterol gallstone model in C57BL/6 mice and evaluate the effects of Lactobacillus intervention on gallstone formation induced by a high-fat diet. In this study, 8-week-old male C57BL/6 mice were randomly divided into four groups: a high-fat diet + saline group (HF-S), a high-fat diet + probiotic group (HF-P), a normal diet + saline group (ND-S), and a normal diet + probiotic group (ND-P), to assess the effect of probiotics on gallstone formation. The results showed significant differences among the four groups in body weight gain, liver weight, gallstone formation, and histopathology. Based on these preliminary findings, we added two more experimental groups: a 2-week probiotic pretreatment + high-fat diet group (Pre2w-HF) and a 4-week probiotic pretreatment + high-fat diet group (Pre4w-HF), to further investigate the dose-dependence and efficacy of probiotic pretreatment. The results indicated that probiotic intervention significantly reduced the incidence and severity of gallstones induced by a high-fat diet, with the pretreatment groups showing more pronounced effects. Histological analysis also revealed that probiotic intervention reduced inflammation and pathological changes in the liver and gallbladder. This study suggests that probiotics have potential therapeutic value in the prevention and treatment of cholesterol gallstones. Future research should explore the effects of different strains and doses, as well as the underlying mechanisms involved.

Effects of Increased Housing Space Without Altering Stocking Density on Body Weight, Stress, and Gut Microbiome in Broiler Chickens

Effects of Increased Housing Space Without Altering Stocking Density on Body Weight, Stress, and Gut Microbiome in Broiler Chickens

Effect of Feeding Human Milk on Development of the Infant Immune System and Allergic Outcomes-An Area of Research Challenge and Need.

Surprisingly little is known about the effect of breastfeeding on the infant's immune system development. Systematic reviews have suggested the role of breastfeeding in the prevention against asthma, autoimmune diseases, inflammatory bowel disease, and childhood leukemia. However, studies on atopic disease suffer from reverse causation, small size, and those assessing food allergy (FA) have often relied on parent-reported outcomes. Randomized controlled trials (RCTs) are not possible for ethical reasons. In addition, epidemiological studies have not considered that there is a large interindividual variation in human milk (HM) composition and feeding at the breast versus pumped HM potentially impacting the effect of breastfeeding between mothers. While prevention strategies such as early introduction of highly allergenic food are impactful in preventing peanut and egg allergies, implementation of early introduction guidelines has been slow, and many infants are already sensitized by 4-6 months of age. To be more effective, primary prevention strategies must commence much earlier, during breastfeeding. There are studies that imply a definitive effect of breastfeeding on the gut microbiome and regulatory T cells (Tregs) as well as a higher rate of FA in populations with historically low rates of breastfeeding. These provide a strong rationale for assessing the effect of feeding HM in the context of HM composition and mode of feeding on immune development. The lack of well-conducted, large studies assessing the role of breastfeeding and HM composition in the development of immune system development is a significant gap when designing prevention strategies.

PyBootNet: a python package for bootstrapping and network construction

Background Network analysis has emerged as a tool for investigating interactions among species in a community, interactions among genes or proteins within cells, or interactions across different types of data (e.g., genes and metabolites). Two aspects of networks that are difficult to assess are the statistical robustness of the network and whether networks from two different biological systems or experimental conditions differ. Methods PyBootNet is a user-friendly Python package that integrates bootstrapping analysis and correlation network construction. The package offers functions for generating bootstrapped network metrics, statistically comparing network metrics among datasets, and visualizing bootstrapped networks. PyBootNet is designed to be accessible and efficient with minimal dependencies and straightforward input requirements. To demonstrate its functionality, we applied PyBootNet to compare correlation networks derived from study using a mouse model to investigate the impacts of Polycystic Ovary Syndrome (PCOS) on the gut microbiome. PyBootNet includes functions for data preprocessing, bootstrapping, correlation matrix calculation, network statistics computation, and network visualization. Results We show that PyBootNet generates robust bootstrapped network metrics and identifies significant differences in one or more network metrics between pairs of networks. Our analysis of the previously published PCOS gut microbiome data also showed that our network analysis uncovered patterns and treatment effects missed in the original study. PyBootNet provides a powerful and extendible Python bioinformatics solution for bootstrapping analysis and network construction that can be applied to microbes, genes, metabolites and other biological data appropriate for network correlation comparison and analysis.

Dietary and environmental factors affecting the dynamics of the gut bacteria in Tibetan Awang sheep (Ovis aries) across divergent breeding models

IntroductionTibetan Awang sheep (Ovis aries), indigenous to the Qinghai-Tibet Plateau, are highly adapted to high-altitude environment. However, knowledge regarding their gut bacterial composition remains limited.MethodsA comprehensive 16S rRNA highthroughput sequencing was performed on fecal samples from 15 Awang sheep under pure grazing, semi-captivity, and full captivity breeding models.ResultsOur results revealed that Firmicutes and Bacteroidetes were the most abundant bacterial phyla, while Christensenellaceae_R-7_group, Romboutsia, Rikenellaceae_RC9_gut_group, Ruminococcus, and Bacteroides were prevalent genera in the gut microbiota of Awang sheep. Meanwhile, the predominant presence of Bacteroides with increasing altitude of breeding locations indirectly demonstrates its crucial role in mediating energy acquisition among Awang sheep at high altitudes. Furthermore, PCoA and ANOSIM analysis exhibited significant differences in bacterial composition across all breeding models (r > 0.6, p < 0.001). Christensenellaceae_R-7_group, Romboutsia, and Ruminococcus were significantly abundant in the pure grazing breeding model, while Rikenellaceae_RC9_gut_group and Bacteroides were more abundant in the semi-captivity breeding model. An abnormally high abundance of Acinetobacter indicated a potential risk of Acinetobacter infection in the fully captive group. The environmental association analysis exhibited that meadows diet (R2 = 0.938, Pr[>r] = 0.001) and altitude (R2 = 0.892, Pr[>r] = 0.001) had significant effects on the dominant genera, explaining a substantial proportion of the total variation in community composition.DiscussionOur study indicated that breeding conditions significantly impact the gut microbiota of Awang sheep. The environmental association analysis underscores the importance of diet and altitude in shaping the gut microbiota of Awang sheep. The present findings provide insights into the microbiota dynamics of Awang sheep and offer guidance for their scientific husbandry management.

Tributyl Phosphate Induced Male Reproductive Toxicity in Mice.

Tributyl phosphate (TBP) is an emerging hazardous material that is ubiquitous in the environment. However, whether TBP affects the male reproductive system remains unknown. In this study, we exposed male ICR mice and mouse spermatocyte GC-2 cells to TBP to explore the male reproductive toxicity of TBP. The results revealed that TBP (50 and 100 mg·kg-1·day-1) decreased sperm count and motility, damaged testicular structure, and induced apoptosis in mice after 35 days of oral gavage. TBP (10, 50, and 200 μM) inhibited cell viability, induced apoptosis, and reduced the ratio of BCL2/BAX in GC-2 cells after 24 h of exposure. TBP (50 and 200 μM) triggered the buildup of reactive oxygen species and induced a reduction in the mitochondrial membrane potential within GC-2 cells. In addition, TBP led to gut microbiota dysbiosis and metabolic profile alterations and increased the abundance of Prevotellaceae, which are negatively associated with sperm motility. Furthermore, TBP caused inflammation, induced the infiltration of Th17 cells into the mouse small intestine, and stimulated IL-17A signaling in mouse testes. In conclusion, TBP induced male reproductive toxicity via the gut-testis axis, oxidative stress, and apoptosis, offering fresh perspectives on TBP's reproductive hazards in male mammals.

Microbiome as a modulator of immunotherapy response in pancreatic cancer

Pancreatic adenocarcinoma is widely regarded as one of the most lethal malignancies due to its rapid progression and the limited success of early detection methods and therapeutic interventions. While immunotherapy has emerged as an effective treatment option for various solid tumors, it has not demonstrated comparable efficacy in pancreatic cancer. Further research is required to evaluate the safety and efficacy of different immunotherapy modalities, including immune checkpoint inhibitors, T-cell transfer therapy, chimeric antigen receptor T-cell therapy, neoantigen vaccines, and epigenome-targeting treatments, specifically in the context of pancreatic cancer. Emerging evidence highlights the crucial role of the microbiome in modulating cancer cells’ responses to immunotherapy. Studies have increasingly implicated the gut microbiota composition as a direct influencer of tumorigenesis in pancreatic cancer. Certain microbial species have been shown to exert immunostimulatory or immunosuppressive effects on pancreatic cancer cells, thereby directly enhancing or suppressing their response to immunotherapeutic regimens. Despite these findings, there remains a paucity of comprehensive reviews on microbiome studies specific to individual immunotherapy modalities in pancreatic cancer. This review highlights the exciting potential of the microbiome in modulating pancreatic cancer responses across various immunotherapy subtypes and emphasizes the clinical need for further research in the field.