The role of faecal microbiota transplantation in the treatment of inflammatory bowel disease

Gut microbiota in Crohn's disease pathogenesis

Inflammatory bowel diseases (IBDs) are classified into two distinct types based on the area and severity of inflammation: Crohn's disease (CD) and ulcerative colitis. In CD, gut bacteria can infiltrate mesenteric fat, causing expansion known as creeping fat, which may limit bacterial spread and inflammation but can promote fibrosis. The gut bacteria composition varies depending on whether the colon or ileum is affected. Fecal microbiota transplantation (FMT) transfers feces from a healthy donor to restore gut microbiota balance, often used in IBD patients to reduce inflammation and promote mucosal repair. The use of FMT for CD remains uncertain, with insufficient evidence to fully endorse it as a definitive treatment. While some studies suggest it may improve symptoms, questions about the duration of these improvements and the need for repeated treatments persist. There is a pressing need for methods that provide long-term benefits, as highlighted by Wu et al's research.

Evaluation of the Suitability of Selecting a Faecal Microbiota Transplant: Bacterial Composition and Subsequent Long-Term Monitoring of the Viability of Its Frozen and Lyophilised Forms

Objectives: The aim of this study was to confirm the effectiveness of FMT on the basis of optimum composition of the faecal microbiota of the donor for support therapy in patients with ulcerative colitis, and to observe the viability of the microbiota in frozen and lyophilised administration forms of FMT under various storage conditions. Methods: The bacterial microbiota composition of the FMT samples was assessed using amplicon sequencing via next-generation sequencing (NGS) technology, conducted on the Illumina MiSeq platform. The BD FACS Canto flow cytometer was used to analyse the metabolic activity of FMT samples. Results: FMT analysis confirmed the presence of key butyrate-producing organisms, specifically highlighting species such as Bifidobacterium adolescentis, Faecalibacterium prausnitzi, Coprococcus catus, Eubacterium rectale, alongside contributions from genera Roseburia and Blautia. These organisms play a crucial role in maintaining intestinal health in humans. The viable microorganism counts were significantly higher (p < 0.001) in the frozen form of FMT (−70 °C) in comparison to lyophilised forms (−70 °C, 4 °C and 20 °C) throughout the storage period. Conclusion: The conducted NGS analyses allowed us to confirm the suitability of our FMT donor as a potential candidate for the target group of patients diagnosed with ulcerative colitis. From the point of view of optimum utilisation of FMT at its highest metabolic activity for the purpose of transplantation, its storage for a maximum of 2 months under specified conditions was confirmed as the most suitable for the frozen and all lyophilised FMT forms.

Effect of Moringa oleifera leaf polysaccharide on the composition of intestinal microbiota in mice with dextran sulfate sodium-induced ulcerative colitis

Moringa oleifera (M. oleifera) is a natural plant that has excellent nutritional and medicinal potential. M. oleifera leaves (MOL) contain several bioactive compounds. The aim of this study was to evaluate the potential effect of MOL polysaccharide (MOLP) on intestinal flora in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice. DSS-induced colitis was deemed to be a well-characterized experimental colitis model for investigating the protective effect of drugs on UC. In this study, we stimulated the experimental mice with DSS 4% for 7 days and prepared the high dose of MOLP (MOLP-H) in order to evaluate its effect on intestinal flora in DSS-induced UC mice, comparing three experimental groups, including the control, DSS model, and DSS + MOLP-H (100 mg/kg/day). At the end of the experiment, feces were collected, and the changes in intestinal flora in DSS-induced mice were analyzed based on 16S rDNA high throughput sequencing technology. The results showed that the Shannon, Simpson, and observed species indices of abundance decreased in the DSS group compared with the control group. However, the indices mentioned above were increased in the MOLP-H group. According to beta diversity analysis, the DSS group showed low bacterial diversity and the distance between the control and MOLP-H groups, respectively. In addition, compared with the control group, the relative abundance of Firmicutes in the DSS group decreased and the abundance of Helicobacter increased, while MOLP-H treatment improves intestinal health by enhancing the number of beneficial organisms, including Firmicutes, while reducing the number of pathogenic organisms, such as Helicobacter. In conclusion, these findings suggest that MOLP-H may be a viable prebiotic with health-promoting properties.

Beneficial Effect of Faecal Microbiota Transplantation on Mild, Moderate and Severe Dextran Sodium Sulphate-Induced Ulcerative Colitis in a Pseudo Germ-Free Animal Model

Transplantation of faecal microbiota (FMT) is generally considered a safe therapeutic procedure with few adverse effects. The main factors that limit the spread of the use of FMT therapy for idiopathic inflammatory bowel disease (IBD) are the necessity of minimising the risk of infection and transfer of another disease. Obtaining the animal model of UC (ulcerative colitis) by exposure to DSS (dextran sodium sulphate) depends on many factors that significantly affect the result. Per os intake of DSS with water is individual for each animal and results in the development of a range of various forms of induced UC. For this reason, the aim of our study was to evaluate the modulation and regenerative effects of FMT on the clinical and histopathological responses and the changes in the bowel microenvironment in pseudo germ-free (PGF) mice of the BALB/c line subjected to chemical induction of mild, moderate and serious forms of UC. The goal was to obtain new data related to the safety and effectiveness of FMT that can contribute to its improved and optimised use. The animals with mild and moderate forms of UC subjected to FMT treatment exhibited lower severity of the disease and markedly lower damage to the colon, including reduced clinical and histological disease index and decreased inflammatory response of colon mucosa. However, FMT treatment failed to achieve the expected therapeutic effect in animals with the serious form of UC activity. The results of our study indicated a potential safety risk involving development of bacteraemia and also translocation of non-pathogenic representatives of bowel microbiota associated with FMT treatment of animals with a diagnosed serious form of UC.

Inflammatory bowel disease and Clostridium difficile infection: clinical presentation, diagnosis, and management

As a frequent complication of inflammatory bowel disease (IBD), Clostridium difficile infection (CDI) was confirmed to not only aggravate the symptoms of IBD but also result in unexpected outcomes, including death. With the increasing prevalence rate of IBD and the updating of CDI diagnosis, the incidence of CDI in IBD patients is also seen rising. Although a detection method consisting of glutamate dehydrogenase immunoassay or nucleic acid amplification test and then toxin A/B enzyme immunoassay was recommended and widely adopted, the diagnosis of CDI in IBD is still a challenge because of the overlap between the symptoms of CDI in IBD and CDI itself. Vancomycin and fidaxomicin are the first-line therapy for CDI in IBD; however, the treatment has different effects due to the complexity of IBD patients' conditions and the choice of different treatment schemes. Although the use of fecal microbial transplantation is now in the ascendant for IBD management, the prospects are still uncertain and the prevention and treatment of the recurrence of CDI in IBD remain a clinical challenge. In this paper, the epidemiology, pathophysiology, clinical manifestation, prevention, and therapy of CDI in IBD were summarized and presented.

Modulating the Microbiome for Crohn's Disease Treatment

The central role of the gut microbiota in the regulation of health and disease has been convincingly demonstrated. Polymicrobial interkingdom interactions between bacterial (the bacteriome) and fungal (the mycobiome) communities of the gut have become a prominent focus for development of potential therapeutic approaches. In addition to polymicrobial interactions, the complex gut ecosystem also mediates interactions between the host and the microbiota. These interactions are complex and bidirectional; microbiota composition can be influenced by host immune response, disease-specific therapeutics, antimicrobial drugs, and overall ecosystems. However, the gut microbiota also influences host immune response to a drug or therapy by potentially transforming the drug's structure and altering bioavailability, activity, or toxicity. This is especially true in cases where the gut microbiota has produced a biofilm. The negative ramifications of biofilm formation include alteration of gut permeability, enhanced antimicrobial resistance, and alteration of host immune response effectiveness. Natural modulation of the gut microbiota, using probiotic and prebiotic approaches, may also be used to affect the host microbiome, a type of "natural" modulation of the host microbiota composition. In this review, we discuss potential bidirectional interactions between microbes and host, and we describe the changes in gut microbiota induced by probiotic and prebiotic approaches as well as their potential clinical consequences, including biofilm formation. We outline a systematic approach to designing probiotics capable of altering the host microbiota in disease states, using Crohn's disease as a model chronic disease. Understanding how the effective changes in the microbiome may enhance treatment efficacy may unlock the possibility of modulating the gut microbiome to improve treatment using a natural approach.

Drivers and determinants of strain dynamics following fecal microbiota transplantation

Fecal microbiota transplantation (FMT) is a therapeutic intervention for inflammatory diseases of the gastrointestinal tract, but its clinical mode of action and subsequent microbiome dynamics remain poorly understood. Here we analyzed metagenomes from 316 FMTs, sampled pre and post intervention, for the treatment of ten different disease indications. We quantified strain-level dynamics of 1,089 microbial species, complemented by 47,548 newly constructed metagenome-assembled genomes. Donor strain colonization and recipient strain resilience were mostly independent of clinical outcomes, but accurately predictable using LASSO-regularized regression models that accounted for host, microbiome and procedural variables. Recipient factors and donor–recipient complementarity, encompassing entire microbial communities to individual strains, were the main determinants of strain population dynamics, providing insights into the underlying processes that shape the post-FMT gut microbiome. Applying an ecology-based framework to our findings indicated parameters that may inform the development of more effective, targeted microbiome therapies in the future, and suggested how patient stratification can be used to enhance donor microbiota colonization or the displacement of recipient microbes in clinical practice.

Machine Learning Based Microbiome Signature to Predict Inflammatory Bowel Disease Subtypes

Inflammatory bowel disease (IBD) is a chronic disease with unknown pathophysiological mechanisms. There is evidence of the role of microorganims in this disease development. Thanks to the open access to multiple omics data, it is possible to develop predictive models that are able to prognosticate the course and development of the disease. The interpretability of these models, and the study of the variables used, allows the identification of biological aspects of great importance in the development of the disease. In this work we generated a metagenomic signature with predictive capacity to identify IBD from fecal samples. Different Machine Learning models were trained, obtaining high performance measures. The predictive capacity of the identified signature was validated in two external cohorts. More precisely a cohort containing samples from patients suffering Ulcerative Colitis and another from patients suffering Crohn's Disease, the two major subtypes of IBD. The results obtained in this validation (AUC 0.74 and AUC = 0.76, respectively) show that our signature presents a generalization capacity in both subtypes. The study of the variables within the model, and a correlation study based on text mining, identified different genera that play an important and common role in the development of these two subtypes.

Safety and efficacy of fecal microbiota transplantation for treatment of systemic lupus erythematosus: An EXPLORER trial

Gut microbiota dysbiosis is involved in the development of systemic lupus erythematosus (SLE). The safety and efficacy of fecal microbiota transplantation (FMT) for the treatment of SLE patients has not been explored. In this 12-week, single-arm pilot clinical trial of oral encapsulated fecal microbiome from healthy donors to patients with active SLE, we aimed to evaluate the safety and efficacy of FMT in patients with SLE (ChiCTR2000036352). 20 SLE patients with SLEDAI ≥6 were recruited. FMT was administered once a week for three consecutive weeks along with standard treatment and the patients were followed for 12 weeks. Safety was evaluated throughout the trial. The primary endpoint was the SLE Responder Index-4 (SRI-4) at week 12. Microbiome composition, levels of short chain fatty acids (SCFAs) in the gut and of cytokines in the sera were measured along with lymphocyte phenotyping. No serious adverse events were observed after FMT. At week 12, the SRI-4 response rate was 42.12%, and significant reductions in the SLEDAI-2K scores and the level of serum anti-dsDNA antibody were observed compared to baseline. Significant enrichment of SCFAs-producing bacterial taxa and reduction of inflammation-related bacterial taxa were observed, along with increased production of SCFAs in the gut and reduced levels of IL-6 and CD4⁺ memory/naïve ratio in the peripheral blood. Furthermore, SRI-4 responding patients displayed specific microbiota signatures both before and after FMT. The first clinical trial of FMT in active SLE patients provide supportive evidence that FMT might be a feasible, safe, and potentially effective therapy in SLE patients by modifying the gut microbiome and its metabolic profile.

Beneficial Effects of Celastrol on Immune Balance by Modulating Gut Microbiota in Experimental Ulcerative Colitis Mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease caused by many factors including colonic inflammation and microbiota dysbiosis. Previous studies have indicated that celastrol (CSR) has strong anti-inflammatory and immune-inhibitory effects. Here, we investigated the effects of CSR on colonic inflammation and mucosal immunity in an experimental colitis model, and addressed the mechanism by which CSR exerts the protective effects. We characterized the therapeutic effects and the potential mechanism of CSR on treating UC using histological staining, intestinal permeability assay, cytokine assay, flow cytometry, fecal microbiota transplantation (FMT), 16S rRNA sequencing, untargeted metabolomics, and cell differentiation. CSR administration significantly ameliorated the dextran sodium sulfate (DSS)-induced colitis in mice, which was evidenced by the recovered body weight and colon length as well as the decreased disease activity index (DAI) score and intestinal permeability. Meanwhile, CSR down-regulated the production of pro-inflammatory cytokines and up-regulated the amount of anti-inflammatory mediators at both mRNA and protein levels, and improved the balances of Treg/Th1 and Treg/Th17 to maintain the colonic immune homeostasis. Notably, all the therapeutic effects were exerted in a gut microbiota-dependent manner. Furthermore, CSR treatment increased the gut microbiota diversity and changed the compositions of the gut microbiota and metabolites, which is probably associated with the gut microbiota-mediated protective effects. In conclusion, this study provides the strong evidence that CSR may be a promising therapeutic drug for UC.

Small intestinal bacterial overgrowth in patients with inflammatory bowel disease: A case-control study

BACKGROUND

Though small intestinal bacterial overgrowth (SIBO) is known in inflammatory bowel disease (IBD), the data on it are scanty and have limitations.

METHODS

Data on IBD patients undergoing glucose hydrogen breath test (GHBT) were retrospectively analyzed to evaluate the frequency and risk factors of SIBO in IBD compared to 66 healthy controls.

RESULTS

Patients with IBD (n=86; 45 ulcerative colitis [UC] and 41 Crohn's disease [CD]) more often had SIBO on GHBT than the healthy subjects (16/86 [18.6%] vs. 1/66 [1.5%]; p=0.002). SIBO was commoner among patients with CD than UC (14/41 [34.1%] vs. 2/45 [4.4%]; p=0.001). The frequency of SIBO among UC patients was comparable to healthy subjects (2/45 [4.4%] vs. 1/66 [1.5%]; p=not significant [NS]). Patients with CD than those with UC had higher values of maximum breath hydrogen and a greater area under the curve for breath hydrogen. Other factors associated with SIBO included female gender (11/16 [68.8%] with vs. 21/70 [30%] without SIBO; p=0.003), and having undergone surgery (8/16 [50%] vs. 6/70 [8.6%]; p=0.0002). SIBO patients had lower levels of total serum protein and albumin than those without SIBO (6.2 ± 1.5 g/dL vs. 7.0 ± 0.9 g/dL, respectively; p=0.009 and 3.5 ± 0.9 g/dL vs. 4.0 ± 0.6 g/dL, respectively; p=0.02). CD, female gender, and surgery for IBD tended to be the independent factors associated with SIBO among IBD patients on multivariate analysis.

CONCLUSIONS

Patients with IBD, particularly CD, female, and those having undergone surgery, have a higher risk of SIBO than the healthy controls.

Fecal microbiota transplantation for recurrent C. difficile infection in patients with inflammatory bowel disease: experience of a large-volume European FMT center

Inflammatory bowel disease (IBD) is a risk factor for C. difficile infection (CDI), which, in turn, complicates the clinical course of IBD. Fecal microbiota transplantation (FMT) is safe and effective in patients with IBD and recurrent CDI (rCDI). In our study, patients with IBD and rCDI received FMT by colonoscopy and were followed-up for 8 weeks. The primary outcome was negative C. difficile toxin 8 weeks after FMT. Eighteen patients with IBD were enrolled. Eight patients received sequential FMT either for pseudomembranous colitis or failure of single fecal infusion. At 8-week follow-up the C. difficile toxin was negative in 17 patients, and most (83%) experienced also improvement of IBD disease activity. Overall, we did not observe any serious adverse event.FMT appears to be highly effective and safe in patients with IBD and rCDI and is likely not only to eradicate CDI but also to improve disease activity of IBD.

Gut microbiota in inflammatory bowel disease: a target for therapy not to be missed

In the last years, the gut microbiota achieved great importance, since several studies demonstrated its correlation with the immune system and with the maintenance of intestinal homeostasis, as well as with the regulation of the integrity of the epithelium and the intestinal motility. An imbalance in microbial species promotes a dysbiosis, which has been associated with chronic diseases such as metabolic syndrome, inflammatory diseases, and some behavior disorders. The association with gut microbiota and dysbiosis has been demonstrated mostly in inflammatory bowel disease (IBD). Several studies investigated the application of antibiotics, prebiotics, probiotics, and fecal microbiota transplantation in the treatment strategies for IBD. In this review, we discuss the recent findings on the potential role of the gut microbiota manipulation, with particular attention to bacterial microbiota, which could be implicated for a successful IBD therapeutic approach.

Treatment of Inflammatory Bowel Disease: A Comprehensive Review

Inflammatory bowel disease (IBD), as a global disease, has attracted much research interest. Constant research has led to a better understanding of the disease condition and further promoted its management. We here reviewed the conventional and the novel drugs and therapies, as well as the potential ones, which have shown promise in preclinical studies and are likely to be effective future therapies. The conventional treatments aim at controlling symptoms through pharmacotherapy, including aminosalicylates, corticosteroids, immunomodulators, and biologics, with other general measures and/or surgical resection if necessary. However, a considerable fraction of patients do not respond to available treatments or lose response, which calls for new therapeutic strategies. Diverse therapeutic options are emerging, involving small molecules, apheresis therapy, improved intestinal microecology, cell therapy, and exosome therapy. In addition, patient education partly upgrades the efficacy of IBD treatment. Recent advances in the management of IBD have led to a paradigm shift in the treatment goals, from targeting symptom-free daily life to shooting for mucosal healing. In this review, the latest progress in IBD treatment is summarized to understand the advantages, pitfalls, and research prospects of different drugs and therapies and to provide a basis for the clinical decision and further research of IBD.

Lyophilised oral faecal microbiota transplantation for ulcerative colitis (LOTUS): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Faecal microbiota transplantation (FMT) delivered via colonoscopic infusion or enemas have been shown to induce remission in a proportion of patients with active ulcerative colitis. Whether orally administered FMT is effective in ulcerative colitis is unknown. We aimed to assess the efficacy of oral lyophilised FMT for the treatment of active ulcerative colitis.

METHODS

A double-blind, randomised, placebo-controlled trial was conducted at two centres in Australia. Eligible patients were aged 18-75 years with active ulcerative colitis (defined as clinical and endoscopic active ulcerative colitis, with a total Mayo score of 4-10, and a Mayo endoscopic subscore ≥1). After 2 weeks of amoxicillin, metronidazole, and doxycycline, patients were randomly assigned in a 1:1 ratio to receive either oral lyophilised FMT or placebo capsules for 8 weeks, using a prespecified computer-generated randomisation list with a permuted block size of 8. The primary outcome was corticosteroid-free clinical remission with endoscopic remission or response (total Mayo score ≤2, all subscores ≤1, and ≥1 point reduction in endoscopic subscore) at week 8. At week 8, FMT responders were randomly assigned (in a 1:1 ratio, permuted block size of 8) to either continue or withdraw FMT for a further 48 weeks. Analyses were done by modified intention-to-treat, including all patients who received at least one study dose. This trial is registered with Australian New Zealand Trial Registry, number ACTRN 12619000611123; this is the final report of the trial.

FINDINGS

Between May 20, 2019, and March 24, 2020, 35 patients were randomly assigned: 15 to receive FMT and 20 to receive placebo. Recruitment was terminated early due to the COVID-19 pandemic. At week 8, eight (53%) of 15 patients in the FMT group were in corticosteroid-free clinical remission with endoscopic remission or response, as were three (15%) of 20 patients in the placebo group (difference 38·3%, 95% CI 8·6-68·0; p=0·027; odds ratio 5·0, 95% CI 1·8-14·1). Adverse events occurred in 10 (67%) patients in the FMT group and 17 (85%) of those in the placebo group during the 8-week induction period, and were generally mild and self-limiting gastrointestinal complaints. Serious adverse events included worsening ulcerative colitis (two in the FMT group, one in the placebo group) and per-rectal bleeding (one in the placebo group). Ten patients in the FMT group who achieved a clinical or endoscopic response entered the maintenance phase and were randomly assigned to continue open-label FMT (n=4) or withdraw therapy (n=6). All four (100%) patients who continued FMT were in clinical, endoscopic, and histologic remission at week 56 compared with none of the patients who had FMT withdrawn.

INTERPRETATION

Antibiotics followed by orally administered FMT was associated with the induction of remission in patients with active ulcerative colitis. Continuing FMT was well tolerated and appeared to demonstrate clinical, endoscopic, and histological efficacy. Oral FMT could be a promising and feasible treatment option for patients with ulcerative colitis.

FUNDING

St Vincent's Clinic Foundation, Gastroenterological Society of Australia, Gutsy Group.

Dynamic Properties of the Intestinal Ecosystem Call for Combination Therapies, Targeting Inflammation and Microbiota, in Ulcerative Colitis

BACKGROUND & AIMS

Intestinal microbiota-host interactions play a major role in health and disease. This has been documented at the microbiota level ("dysbiosis" in chronic immune-mediated diseases) and through the study of specific bacteria-host interactions but rarely at the level of intestinal ecosystem dynamics. However, understanding the behavior of this ecosystem may be key to the successful treatment of disease. We recently postulated that health and disease represent alternative stable states of the intestinal ecosystem (different configurations that can exist under identical external conditions), which would require adapted strategies in disease treatment. Here, we examine if alternative stable states indeed exist in this ecosystem and if they could affect remission from ulcerative colitis (UC).

METHODS

We analyzed data from a study on pediatric UC. The data reflect current treatment practice following the recruitment of treatment-naive patients with new-onset disease. Patients received personalized anti-inflammatory treatments over a period of 1 year. Stool samples at 0, 4, 12, and 52 weeks allowed an estimation of microbiota status (through 16S ribosomal RNA gene sequencing) and host inflammatory status (through the measurement of fecal calprotectin levels).

RESULTS

We identify 4 microbiota states and 4 host states. Longitudinal data show that the improvement of inflammatory status is accompanied by an improvement of microbiota status. However, they also provide strong indications that both improvements are retarded or blocked by alternative states barriers.

CONCLUSIONS

Our observations strongly suggest that inflammation suppression should be combined with microbiota management where possible to improve the efficacy of UC treatment.

Crosstalk between gut microbiota and sepsis

Sepsis is an overwhelming inflammatory response to microbial infection. Sepsis management remains a clinical challenge. The role of the gut microbiome in sepsis has gained some attention. Recent evidence has demonstrated that gut microbiota regulate host physiological homeostasis mediators, including the immune system, gut barrier function and disease susceptibility pathways. Therefore, maintenance or restoration of microbiota and metabolite composition might be a therapeutic or prophylactic target against critical illness. Fecal microbiota transplantation and supplementation of probiotics are microbiota-based treatment methods that are somewhat limited in terms of evidence-based efficacy. This review focuses on the importance of the crosstalk between the gastrointestinal ecosystem and sepsis to highlight novel microbiota-targeted therapies to improve the outcomes of sepsis treatment.

[Efficacy and Safety of Fecal Microbiota Transplantation and Prospect of Microbe-based Therapies for Inflammatory Bowel Disease]

The use of 5-ASA, immunomodulators, biologics, and small molecule drugs are the main treatment for inflammatory bowel disease (IBD), however, fecal microbiota transplantation (FMT) is also drawing attention as a treatment to improve intestinal dysbiosis by transplantaing normal human stool into patients with IBD. FMT demonstrates relatively good effects in inducing clinical remission in IBD, but unlike Clostridium difficile infection, multiple FMT can enhance the clinical effect. There are no reports of the long-term effectiveness and safety of FMT conducted in IBD yet, therefore, well-designed, prospective studies will be needed. Gut microbiota can affect inflammatory response, intestinal barrier function, and host metabolism, so microbe-based therapies are likely to be a new treatment option for IBD. The deeper the understanding of microbe products or effectors, the more likely it is to provide personalized therapy in IBD.

Fecal Microbiota Transplantation beyond Clostridioides Difficile Infection

With advancing analytical methods for gut microbes, many studies have been conducted, revealing that gut microbes cause various diseases, including gastrointestinal and non-gastrointestinal diseases. Accordingly, studies have been actively conducted to analyze the effects on the prevention and treatment of these diseases through changes in intestinal microbes and control of dysbiosis. Fecal microbiota transplantation (FMT) is an effort and is currently being applied to Clostridioides difficile treatment in Korea. Many studies have demonstrated the application of FMT in inflammatory bowel disease, irritable bowel syndrome, non-alcoholic fatty liver disease, metabolic syndrome, obesity, and diabetes. With further studies and accumulation of evidence, FMT could help treat presently untreatable diseases in clinical practice.

No Worm Is an Island; The Influence of Commensal Gut Microbiota on Cyathostomin Infections

Simple Summary

There is increasing evidence for the importance of gut bacteria in animal health and disease. This is particularly relevant for gastrointestinal infections, such as parasitic worms, which share a niche with gut bacteria. Parasitic worms are highly prevalent in domestic horses and are a significant cause of disease in this population. This commentary explores the complex relationships between the most common parasitic worm in horses (cyathostomins) and gut bacteria, based on recent studies in horses and other species. We propose novel theories and avenues for research that harness these relationships and have the potential to improve control of parasitic worms, and overall equine health, in the future.

Abstract

The importance of the gut microbiome for host health has been the subject of intense research over the last decade. In particular, there is overwhelming evidence for the influence of resident microbiota on gut mucosal and systemic immunity; with significant implications for the outcome of gastrointestinal (GI) infections, such as parasitic helminths. The horse is a species that relies heavily on its gut microbiota for GI and overall health, and disturbances in this complex ecosystem are often associated with life-threatening disease. In turn, nearly all horses harbour parasitic helminths from a young age, the most prevalent of which are the small strongyles, or cyathostomins. Research describing the relationship between gut microbiota and cyathostomin infection is in its infancy, however, to date there is evidence of meaningful interactions between these two groups of organisms which not only influence the outcome of cyathostomin infection but have long term consequences for equine host health. Here, we describe these interactions alongside supportive evidence from other species and suggest novel theories and avenues for research which have the potential to revolutionize our approach to cyathostomin prevention and control in the future.