Systematic review with meta-analysis: encapsulated faecal microbiota transplantation - evidence for clinical efficacy

Should the Faecal Microbiota Composition Be Determined to Certify a Faecal Donor?

BACKGROUND/OBJECTIVES

Faecal microbiota transplantation (FMT) is considered a safe and effective therapy for recurrent Clostridioides difficile infection. It is the only current clinical indication for this technique, although numerous clinical research studies and trials propose its potential usefulness for treating other pathologies. Donor selection is a very rigorous process, based on a personal lifestyle interview and the absence of known pathogens in faeces and serum, leading to only a few volunteers finally achieving the corresponding certification. However, despite the high amount of data generated from the ongoing research studies relating microbiota and health, there is not yet a consensus defining what is a "healthy" microbiota. To date, knowledge of the composition of the microbiota is not a requirement to be a faecal donor. The aim of this work was to evaluate whether the analysis of the composition of the microbiota by massive sequencing of 16S rDNA could be useful in the selection of the faecal donors.

METHODS

Samples from 10 certified donors from Mikrobiomik Healthcare Company were collected and sequenced using 16S rDNA in a MiSeq (Illumina) platform. Alpha (Chao1 and Shannon indices) and beta diversity (Bray-Curtis) were performed using the bioinformatic web server Microbiome Analyst. The differences in microbial composition at the genera and phyla levels among the donors were evaluated.

RESULTS

The microbial diversity metric by alpha diversity indexes showed that most donors exhibited a similar microbial diversity and richness, whereas beta diversity by 16S rDNA sequencing revealed significant inter-donor differences, with a more stable microbial composition over time in some donors. The phyla Bacillota and Bacteroidota were predominant in all donors, while the density of other phyla, such as Actinomycota and Pseudomonota, varied among individuals. Each donor exhibited a characteristic genera distribution pattern; however, it was possible to define a microbiome core consisting of the genera Agathobacter, Eubacterium, Bacteroides, Clostridia UCG-014 and Akkermansia. Conclusions: The results suggest that donor certification does not need to rely exclusively on their microbiota composition, as it is unique to each donor. While one donor showed greater microbial diversity and richness, clear criteria for microbial normality and health have yet to be established. Therefore, donor certification should focus more on clinical and lifestyle aspects.

Encapsulated donor faeces for faecal microbiota transplantation: the Glyprotect protocol

Background

Faecal microbiota transplantation (FMT) is a highly effective treatment for Clostridioides difficile infection. Its use is backed by solid evidence, but application methods differ. Encapsulated FMT is a non-invasive, patient-friendly and scalable application method that may be preferred over colonoscopy or nasoduodenal tube application.

Objectives

We describe a detailed protocol, the Glyprotect protocol, for producing glycerol-based capsules to increase FMT accessibility.

Design

Using iterative quality improvement methods, we developed and validated the Glyprotect protocol as a reproducible protocol for cryopreserving minimally processed donor faeces in a standard hospital laboratory setting.

Methods

We describe detailed standard operating procedures for producing glycerol-based capsules, including all necessary materials and troubleshooting guidelines. Capsule integrity was tested at various temperatures and pH levels. Flow cytometry was used to measure microbiota counts and dose accuracy.

Results

The Glyprotect protocol has been used for more than 2500 capsule-based FMT treatments and complies with European tissue and cell standards. The protocol is optimised to preserve microbes and minimise modulation of the donated microbiota by removing debris and water, which also reduces the number of capsules needed per FMT treatment. The intestinal microbiota is preserved in glycerol for cryoprotection and to prevent capsule leakage. Each capsule contains 650 µL microbe-glycerol mass, estimated to contain an average of 2.5 × 108 non-specified bacteria.

Conclusion

The Glyprotect protocol enables hospitals and tissue establishments to set up capsule production in a standard laboratory, improving patients' access to FMT. The protocol facilitates the scalability of FMT services because capsule FMT is less time-consuming and less expensive than liquid-suspension FMT applied by colonoscopy or nasojejunal tube.

Trial registration

Not applicable.

Bacterial diversity and specific taxa are associated with decolonization of carbapenemase-producing enterobacterales after fecal microbiota transplantation

OBJECTIVES

We evaluated the effect of fecal microbiota transplantation (FMT) on the clearance of carbapenemase-producing Enterobacterales (CPE) carriage.

METHODS

We performed a prospective, multi-center study, conducted among patients who received a single dose of FMT from one of four healthy donors. The primary endpoint was complete clearance of CPE carriage two weeks after FMT with a secondary endpoint at three months. Shotgun metagenomic sequencing was performed to assess gut microbiota composition of donors and recipients before and after FMT.

RESULTS

Twenty CPE-colonized patients were included in the study, where post-FMT 20% (n = 4/20) of patients met the primary endpoint and 40% (n = 8/20) of patients met the secondary endpoint. Kaplan-Meier curves between patients with FMT intervention and the control group (n = 82) revealed a similar rate of decolonization between groups. Microbiota composition analyses revealed that response to FMT was not donor-dependent. Responders had a significantly lower relative abundance of CPE species pre-FMT than non-responders, and 14 days post-FMT responders had significantly higher bacterial species richness and alpha diversity compared to non-responders (p < 0.05). Responder fecal samples were also enriched in specific species, with significantly higher relative abundances of Faecalibacterium prausnitzii, Parabacteroides distasonis, Collinsella aerofaciens, Alistipes finegoldii and Blautia_A sp900066335 (q<0.01) compared to non-responders.

CONCLUSION

FMT administration using the proposed regimen did not achieve statistical significance for complete CPE decolonization but was correlated with the relative abundance of specific bacterial taxa, including CPE species.

Past, present, and future of microbiome-based therapies

Technological advances in studying the human microbiome in depth have enabled the identification of microbial signatures associated with health and disease. This confirms the crucial role of microbiota in maintaining homeostasis and the host health status. Nowadays, there are several ways to modulate the microbiota composition to effectively improve host health; therefore, the development of therapeutic treatments based on the gut microbiota is experiencing rapid growth. In this review, we summarize the influence of the gut microbiota on the development of infectious disease and cancer, which are two of the main targets of microbiome-based therapies currently being developed. We analyze the two-way interaction between the gut microbiota and traditional drugs in order to emphasize the influence of gut microbial composition on drug effectivity and treatment response. We explore the different strategies currently available for modulating this ecosystem to our benefit, ranging from 1st generation intervention strategies to more complex 2nd generation microbiome-based therapies and their regulatory framework. Lastly, we finish with a quick overview of what we believe is the future of these strategies, that is 3rd generation microbiome-based therapies developed with the use of artificial intelligence (AI) algorithms.

The gut microbiome dysbiosis and regulation by fecal microbiota transplantation: umbrella review

Background

Gut microbiome dysbiosis has been implicated in various gastrointestinal and extra-gastrointestinal diseases, but evidence on the efficacy and safety of fecal microbiota transplantation (FMT) for therapeutic indications remains unclear.

Methods

The gutMDisorder database was used to summarize the associations between gut microbiome dysbiosis and diseases. We performed an umbrella review of published meta-analyses to determine the evidence synthesis on the efficacy and safety of FMT in treating various diseases. Our study was registered in PROSPERO (CRD42022301226).

Results

Gut microbiome dysbiosis was associated with 117 gastrointestinal and extra-gastrointestinal. Colorectal cancer was associated with 92 dysbiosis. Dysbiosis involving Firmicutes (phylum) was associated with 34 diseases. We identified 62 published meta-analyses of FMT. FMT was found to be effective for 13 diseases, with a 95.56% cure rate (95% CI: 93.88-97.05%) for recurrent Chloridoids difficile infection (rCDI). Evidence was high quality for rCDI and moderate to high quality for ulcerative colitis and Crohn's disease but low to very low quality for other diseases.

Conclusion

Gut microbiome dysbiosis may be implicated in numerous diseases. Substantial evidence suggests FMT improves clinical outcomes for certain indications, but evidence quality varies greatly depending on the specific indication, route of administration, frequency of instillation, fecal preparation, and donor type. This variability should inform clinical, policy, and implementation decisions regarding FMT.

Efficacy and safety of fecal microbiota transplantation in the treatment of ulcerative colitis: a systematic review and meta-analysis

To explore the efficacy and safety of fecal microbiota transplantation (FMT) as a treatment approach for ulcerative colitis (UC), a comprehensive systematic review and meta-analysis of randomized controlled trials was conducted. To collect and evaluate randomized controlled trials of high quality on FMT for UC, we searched a number of databases, including PubMed, Web of Science, Cochrane, Embase, and Medline, for studies published between the establishment of the databases and March 2023. We conducted a meta-analysis of the studies using Review Manager software (version 5.4.1) to determine the differences in rates of remission and adverse reactions between the FMT group and the control group, utilizing the risk ratio (RR) and 95% confidence interval (CI) to combine our findings. A total of 13 randomized controlled trials (RCTs) on the efficacy of FMT in patients with UC were included in the study, in which 580 patients participated, including 293 patients treated with FMT and 287 control subjects. Meta-analysis revealed that clinical remission was significantly better in the FMT group than in the control group [RR = 1.73; 95% CI = (1.41, 2.12); P < 0.00001]; endoscopic remission was significantly better in the FMT group than in the control group [RR = 1.74; 95% CI = (1.24, 2.44); P = 0.001]. Additionally, there were no significant differences in the incidence of adverse reactions between the two groups [RR = 1.00; 95% CI = (0.86, 1.15); P = 0.96]. Fecal microbiota transplantation has shown potential as a therapeutic intervention for inducing clinical remission in ulcerative colitis UC; nevertheless, the attainment of endoscopic remission and the maintenance of long-term remission continue to present challenges. Safety concerns persist throughout the treatment process, necessitating the implementation of measures to augment both safety and success rates.

Donor, patient age and exposure to antibiotics are associated with the outcome of faecal microbiota transplantation for recurrent Clostridioides difficile infection: A prospective cohort study

BACKGROUND

Faecal microbiota transplantation (FMT) is effective for recurrent Clostridioides difficile infection (rCDI), but its effect varies inexplicably.

AIMS

To optimise the effectiveness of FMT for rCDI and validate determinants for effect METHODS: We conducted a cohort study, including all patients treated with FMT for rCDI between October 2018 and June 2020. Statistical process control was used to evaluate the impact of prospective quality improvement on the effect of single FMT treatments per 10-11 patients. Targeting an 80% effect, optimisations included changes to processing procedures, preparation and clinical application of FMT. The primary outcome was the resolution of Clostridioides difficile-associated diarrhoea at week 8. If CDI recurred, FMT was repeated. All patients were followed for 8 weeks after their latest FMT.

RESULTS

183 patients with rCDI received 290 FMT treatments. A single FMT achieved resolution at week 8 in 127 (69%, 95% CI: 62%-76%), while repeated FMT cumulatively achieved resolution in 167/183 (91%, 95% CI: 86%-95%). The single FMT effect varied between 36% and 100% over time. In a mixed-effect model, patient age above 65 years, non-rCDI antibiotics at week 1 post-FMT, and donor were associated with effect. Neither increasing the dosages of faecal microbes nor standardising the processing improved outcomes.

CONCLUSION

FMT has a high cumulative effectiveness in patients with rCDI following multiple administrations, but the single FMT effect is variable and may be optimised using statistical process control. Optimising FMT by considering patient age, post-FMT antibiotics, donor and multiple administrations may improve the treatment outcomes.

CLINICALTRIALS

gov (Study identifier: NCT03712722).

Fecal microbiota transplantation for the treatment of irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is the most prevalent gastrointestinal disorder in developed countries and reduces patients’ quality of life, hinders their ability to work, and increases health care costs. A growing number of trials have demonstrated an aberrant gut microbiota composition in IBS, also known as ‘gut dysbiosis’. Fecal microbiota transplantation (FMT) has been suggested as a treatment for IBS.

AIM

To assess the efficacy and safety of FMT for the treatment of IBS.

METHODS

We searched Cochrane Central, MEDLINE, EMBASE and Web of Science up to 24 October 2022 for randomised controlled trials (RCTs) investigating the effectiveness of FMT compared to placebo (including autologous FMT) in treating IBS. The primary outcome was the number of patients with improvements of symptoms measured using a validated, global IBS symptoms score. Secondary outcomes were changes in quality-of-life scores, non-serious and serious adverse events. Risk ratios (RR) and corresponding 95%CI were calculated for dichotomous outcomes, as were the mean differences (MD) and 95%CI for continuous outcomes. The Cochrane risk of bias tool was used to assess the quality of the trials. GRADE criteria were used to assess the overall quality of the evidence.

RESULTS

Eight RCTs (484 participants) were included in the review. FMT resulted in no significant benefit in IBS symptoms three months after treatment compared to placebo (RR 1.19, 95%CI: 0.68-2.10). Adverse events were reported in 97 participants in the FMT group and in 45 participants in the placebo group (RR 1.17, 95%CI: 0.63-2.15). One serious adverse event occurred in the FMT group and two in the placebo group (RR 0.42, 95%CI: 0.07-2.60). Endoscopic FMT delivery resulted in a significant improvement in symptoms, while capsules did not. FMT did not improve the quality of life of IBS patients but, instead, appeared to reduce it, albeit non significantly (MD -6.30, 95%CI: -13.39-0.79). The overall quality of the evidence was low due to moderate-high inconsistency, the small number of patients in the studies, and imprecision.

CONCLUSION

We found insufficient evidence to support or refute the use of FMT for IBS. Larger trials are needed.

Future Modulation of Gut Microbiota: From Eubiotics to FMT, Engineered Bacteria, and Phage Therapy

The human gut is inhabited by a multitude of bacteria, yeasts, and viruses. A dynamic balance among these microorganisms is associated with the well-being of the human being, and a large body of evidence supports a role of dysbiosis in the pathogenesis of several diseases. Given the importance of the gut microbiota in the preservation of human health, probiotics, prebiotics, synbiotics, and postbiotics have been classically used as strategies to modulate the gut microbiota and achieve beneficial effects for the host. Nonetheless, several molecules not typically included in these categories have demonstrated a role in restoring the equilibrium among the components of the gut microbiota. Among these, rifaximin, as well as other antimicrobial drugs, such as triclosan, or natural compounds (including evodiamine and polyphenols) have common pleiotropic characteristics. On one hand, they suppress the growth of dangerous bacteria while promoting beneficial bacteria in the gut microbiota. On the other hand, they contribute to the regulation of the immune response in the case of dysbiosis by directly influencing the immune system and epithelial cells or by inducing the gut bacteria to produce immune-modulatory compounds, such as short-chain fatty acids. Fecal microbiota transplantation (FMT) has also been investigated as a procedure to restore the equilibrium of the gut microbiota and has shown benefits in many diseases, including inflammatory bowel disease, chronic liver disorders, and extraintestinal autoimmune conditions. One of the most significant limits of the current techniques used to modulate the gut microbiota is the lack of tools that can precisely modulate specific members of complex microbial communities. Novel approaches, including the use of engineered probiotic bacteria or bacteriophage-based therapy, have recently appeared as promising strategies to provide targeted and tailored therapeutic modulation of the gut microbiota, but their role in clinical practice has yet to be clarified. The aim of this review is to discuss the most recently introduced innovations in the field of therapeutic microbiome modulation.

Effectiveness and Safety of Colonic and Capsule Fecal Microbiota Transplantation for Recurrent Clostridioides difficile Infection

BACKGROUND & AIMS

Fecal microbiota transplantation (FMT) emerged as rescue treatment for multiply recurrent Clostridioides difficile infections (rCDIs) nonresponsive to standard therapy. However, estimation of FMT efficacy varies among different protocols and formulations, while placebo-controlled clinical trials have excluded most rCDI patients because of medical comorbidities. This study aimed to determine the safety and effectiveness of capsule FMT (cap-FMT) and colonoscopy FMT (colo-FMT) for rCDI using standardized products in a large, multicenter, prospective, real-world cohort.

METHODS

Clinical outcomes and adverse events after FMT performed for rCDI at 6 sites were captured in a prospective registry. FMT was performed using 1 of 2 standardized formulations of microbiota manufactured by the University of Minnesota Microbiota Therapeutics Program, freeze-dried/encapsulated or frozen-thawed/liquid. The FMT administration route was determined by the treating physician. The rCDI cure rate was assessed at 1 and 2 months. Safety data were collected within the first 72 hours and at 1 and 2 months. Logistic regression was used to investigate factors associated with FMT failure.

RESULTS

A total of 301 FMTs were performed in 269 unique patients. Two-thirds were cap-FMT. CDI cure rates were 86% (95% CI, 82%-90%) at 1 month and 81% (95% CI, 75%-86%) at 2 months. There was no difference in the 1-month or 2-month cure rate between cap-FMT and colo-FMT. Cap-FMT recipients were older and less likely to be immunosuppressed or have inflammatory bowel disease. Patient factors of older age and hemodialysis were associated with FMT failure by 2 months on multivariate logistic regression. In addition, post-FMT antibiotic use was associated with FMT failure at 2 months. One serious adverse event was related to colonoscopy (aspiration pneumonia), otherwise no new safety signals were identified.

CONCLUSIONS

Cap-FMT using freeze-dried capsules has a similar safety and effectiveness profile compared with colo-FMT, without the procedural risks of colonoscopy. Although highly effective overall, patient selection is a key factor to optimizing FMT success.

New insights into the treatment of meningoencephalomyelitis of unknown origin since 2009: A review of 671 cases

“Meningoencephalomyelitis of unknown origin” (MUO)—a collective term for a group of clinically-indistinguishable (but pathologically distinct) autoimmune diseases of the CNS—has become increasingly commonly recognized throughout the world. In the 1960s−1980s the focus was primarily on the pathological description of these conditions and, largely anecdotally, their response to glucocorticoids. The subsequent availability of magnetic resonance imaging for companion animals led to a focus on imaging characteristics and response of MUO to various immunosuppressive medications. Previous reviews have not found clear evidence of superiority of any specific treatment regimen. Here, we review outcomes in a further 671 dogs treated with various combinations of glucocorticoids and immunosuppressive drugs and reported since 2009, aiming to determine whether recommendations can be drawn from the material published during more recent decades. We observe that: (i) there is more complete information on outcome of MUO-affected dogs solely receiving glucocorticoids and these reports provide evidence to undermine the dogma that MUO inevitably requires treatment with glucocorticoids plus an immunosuppressive drug; (ii) there is far more information on the pharmacokinetics of cytarabine delivered by a variety of routes, revealing that previous dosing and duration of administration in dogs with MUO may not have been optimal; and, (iii) there is a large number of cases that could be available for entry into multi-institutional randomized controlled trials. Finally, we suggest new research avenues that might aid future clinical trials in MUO through improved understanding of etiological triggers and individual patterns of immune response, such as the impact of the gut microbiome, the potential of CSF flow cytometry, and the establishment of robust clinical scores for evaluation of treatment success.

Early use of faecal microbiota transplantation for C. difficile infection

Overview of: Baunwall SMD, Andreasen SE, Hansen MM, et al Faecal microbiota transplantation for first or second Clostridioides difficile infection (EarlyFMT): a randomised, double-blind, placebo-controlled trial. Lancet Gastroenterol Hepatol 2022;7:1083-91.

Gut microbiota, pathogenic proteins and neurodegenerative diseases

As the world's population ages, neurodegenerative diseases (NDs) have brought a great burden to the world. However, effective treatment measures have not been found to alleviate the occurrence and development of NDs. Abnormal accumulation of pathogenic proteins is an important cause of NDs. Therefore, effective inhibition of the accumulation of pathogenic proteins has become a priority. As the second brain of human, the gut plays an important role in regulate emotion and cognition functions. Recent studies have reported that the disturbance of gut microbiota (GM) is closely related to accumulation of pathogenic proteins in NDs. On the one hand, pathogenic proteins directly produced by GM are transmitted from the gut to the central center via vagus nerve. On the other hand, The harmful substances produced by GM enter the peripheral circulation through intestinal barrier and cause inflammation, or cross the blood-brain barrier into the central center to cause inflammation, and cytokines produced by the central center cause the production of pathogenic proteins. These pathogenic proteins can produced by the above two aspects can cause the activation of central microglia and further lead to NDs development. In addition, certain GM and metabolites have been shown to have neuroprotective effects. Therefore, modulating GM may be a potential clinical therapeutic approach for NDs. In this review, we summarized the possible mechanism of NDs caused by abnormal accumulation of pathogenic proteins mediated by GM to induce the activation of central microglia, cause central inflammation and explore the therapeutic potential of dietary therapy and fecal microbiota transplantation (FMT) in NDs.

Commercially Available Enteric Empty Hard Capsules, Production Technology and Application

Currently, there is a growing need to prepare small batches of enteric capsules for individual therapy or clinical evaluation since many acidic-sensitive substances should be protected from the stomach's acidic environment, including probiotics or fecal material, in the fecal microbiota transplantation (FMT) process. A suitable method seems to be the encapsulation of drugs or lyophilized alternatively frozen biological suspensions in commercial hard enteric capsules prepared by so-called Enteric Capsule Drug Delivery Technology (ECDDT). Manufacturers supply these types of capsules, made from pH-soluble polymers, in products such as AR Caps®, EnTRinsicTM, and Vcaps® Enteric, or capsules made of gelling polymers that release their content as the gel erodes over time when passing through the digestive tract. These include DRcaps®, EMBO CAPS® AP, BioVXR®, or ACGcaps™ HD. Although not all capsules in all formulations meet pharmaceutical requirements for delayed-release dosage forms in disintegration and dissolution tests, they usually find practical application. This literature review presents their composition and properties. Since ECDDT is a new technology, this article is based on a limited number of references.

The Efficacy of Faecal Microbiota Transplant and Rectal Bacteriotherapy in Patients with Recurrent Clostridioides difficile Infection: A Retrospective Cohort Study

The most effective treatment for recurrent Clostridioides difficile infection (CDI) is faecal microbiota transplantation (FMT); however, the optimal route of administration is thus far unknown. This retrospective cohort study of 343 patients sought to evaluate the efficacy of treatment with FMT capsules, FMT enema, and rectal bacteriotherapy (RBT) during a five-year period. The primary endpoint was clinical resolution from CDI after eight weeks, and secondary endpoints were time to recurrence and death during the follow-up period. The proportion of patients with clinical resolution was 79.9% in the FMT capsule group, 53.3% in the FMT enema group, and 61.8% in the RBT group, corresponding to an adjusted odds ratio of 3.79 (CI: 1.82 to 8.26) in the FMT capsule group compared with FMT enema, and 2.92 (CI: 1.49 to 6.03) compared with RBT. The hazards ratio for recurrence within the first 12 months of follow-up was 0.24 (CI: 0.06 to 0.89) in the FMT capsule group compared with FMT enema, and 0.26 (CI: 0.08 to 0.91) compared with RBT. There was no difference in mortality. In conclusion, FMT capsules were more effective than both FMT enema and RBT as treatment of recurrent CDI and reduced the risk of further recurrences.

Gastrointestinal Microbiome and Multiple Health Outcomes: Umbrella Review

In recent years, there has been growing concern about the impact of the gastrointestinal microbiome on human health outcomes. To clarify the evidence for a link between the gastrointestinal microbiome and a variety of health outcomes in humans, we conducted an all-encompassing review of meta-analyses and systematic reviews that included 195 meta-analyses containing 950 unique health outcomes. The gastrointestinal microbiome is related to mortality, gastrointestinal disease, immune and metabolic outcomes, neurological and psychiatric outcomes, maternal and infant outcomes, and other outcomes. Existing interventions for intestinal microbiota (such as probiotics, fecal microbiota transplant, etc.) are generally safe and beneficial to a variety of human health outcomes, but the quality of evidence is not high, and more detailed and well-designed randomized controlled trials are necessary.

Faecal Microbiota Transplantation and Chronic Kidney Disease

Faecal microbiota transplantation (FMT) has attracted increasing attention as an intervention in many clinical conditions, including autoimmune, enteroendocrine, gastroenterological, and neurological diseases. For years, FMT has been an effective second-line treatment for Clostridium difficile infection (CDI) with beneficial outcomes. FMT is also promising in improving bowel diseases, such as ulcerative colitis (UC). Pre-clinical and clinical studies suggest that this microbiota-based intervention may influence the development and progression of chronic kidney disease (CKD) via modifying a dysregulated gut–kidney axis. Despite the high morbidity and mortality due to CKD, there are limited options for treatment until end-stage kidney disease occurs, which results in death, dialysis, or kidney transplantation. This imposes a significant financial and health burden on the individual, their families and careers, and the health system. Recent studies have suggested that strategies to reverse gut dysbiosis using FMT are a promising therapy in CKD. This review summarises the preclinical and clinical evidence and postulates the potential therapeutic effect of FMT in the management of CKD.

The emerging potential of microbiome transplantation on human health interventions

The human microbiome has been the subject of intense research over the past few decades, in particular as a promising area for new clinical interventions. The microbiota colonizing the different body surfaces are of benefit for multiple physiological and metabolic processes of the human host and increasing evidence suggests an association between disturbances in the composition and functionality of the microbiota and several pathological conditions. This has provided a rationale for beneficial modulation of the microbiome. One approach being explored for modulating the microbiota in diseased individuals is transferring microbiota or microbiota constituents from healthy donors via microbiome transplantation. The great success of fecal microbiome transplantation for the treatment of Clostridioides difficile infections has encouraged the application of this procedure for the treatment of other diseases such as vaginal disorders via transplantation of vaginal microbiota, or of skin pathologies via the transplantation of skin microbiota. Microbiome modulation could even become a novel strategy for improving the efficacy of cancer therapies. This review discusses the principle, advantages and limitations of microbiome transplantation as well as different clinical contexts where microbiome transplantation has been applied.