FMT — fecal microbiota transplantation

Fecal microbiota transplantation (FMT) involves transferring gut bacteria from a healthy donor into a patient to restore a disrupted microbial community. This review covers the transition of FMT from an experimental curiosity to an accepted clinical treatment, particularly for recurrent Clostridioides difficile infection (CDI). CDI is a serious gut infection that recurs in 15–20% of patients after initial treatment, and recurrence rates climb to roughly 60% after a first relapse — making conventional antibiotic strategies increasingly ineffective. FMT addresses this by replenishing the diverse, protective microbial ecosystem that antibiotics disrupt, without introducing more antibiotics. Across academic and private clinical settings, FMT resolves recurrent CDI in 81–95% of cases, a striking success rate compared to antibiotic retreatment. Beyond CDI, FMT is being investigated for inflammatory bowel disease (IBD) and chronic gut barrier dysfunction, though evidence in these areas is still accumulating. In Denmark, the procedure is centralized at two major hospitals, reflecting both the promise and the controlled, safety-conscious rollout of this approach.

• FMT achieves 81–95% resolution of recurrent CDI across both academic and private clinical settings, representing a substantial improvement over antibiotic retreatment alone.
• Recurrence of CDI after first-line treatment occurs in 15–20% of patients, escalating to approximately 60% after a first recurrence — the clinical context that makes FMT's efficacy particularly significant.
• For non-CDI indications such as IBD and chronic intestinal barrier dysfunction, evidence supporting FMT is described as growing but not yet as strong as for CDI.
• In Denmark, FMT is performed at Hvidovre Hospital and Aarhus University Hospital, indicating a centralized, regulated clinical implementation rather than widespread ad hoc use.

This is a mechanism review article synthesizing existing clinical and mechanistic evidence on FMT. No primary patient cohort or controlled trial was conducted within this article itself; instead, it aggregates published efficacy and safety data across academic and private-practice settings. The review covers CDI as the primary established indication and surveys emerging evidence for non-CDI indications including IBD and gut barrier dysfunction. Specific follow-up durations and donor/recipient screening protocols are not detailed in the available abstract.

As a mechanism review rather than a primary clinical trial, this article cannot establish causality or provide head-to-head comparisons of FMT protocols, donor selection criteria, or delivery routes (capsule vs. colonoscopic infusion). The wide efficacy range reported (81–95%) likely reflects heterogeneity in patient populations, donor microbiota diversity, and outcome definitions across source studies — sources of variation that a systematic meta-analysis with individual patient data would be better positioned to disentangle. The evidence base for non-CDI indications (IBD, barrier dysfunction) is acknowledged as immature, meaning conclusions there should be treated as directional rather than definitive. Future randomized controlled trials with standardized donor screening, defined microbiome endpoints, and long-term follow-up beyond CDI resolution are needed to clarify durability and to validate FMT in broader indications.

This FMT review sits at the established tier of microbiota-modification therapies and provides a conceptual anchor for several parallel and extending articles in the corpus. It parallels [§143], which examines a quadruple probiotic mixture as an alternative microbiota-based intervention for immune-mediated disease — both articles share the mechanistic premise that restoring microbial community composition confers therapeutic benefit, but FMT operates via wholesale community transfer while probiotics deliver defined strains. It also parallels [§155], which specifically investigates Saccharomyces boulardii's effects on intestinal barrier function — a mechanism directly relevant to FMT's proposed benefit in non-CDI indications involving chronic barrier dysfunction. The review further contextualizes [§154], which addresses FODMAP restriction as a dietary microbiota-modulating strategy for functional gastrointestinal disorders, representing a non-transplant, non-pharmacological route to similar microbiome endpoints. Together, these articles illustrate a spectrum of intervention strategies — from dietary modulation to probiotic supplementation to full microbial community transplantation — all converging on gut microbiota composition as the therapeutic target.

• Saccharomyces Boulardii CNCM I-745 on Intestinal Barrier Function
  Directly addresses intestinal barrier function as a mechanistic outcome — relevant because FMT's proposed benefit in non-CDI indications centers on restoring barrier integrity, making this a useful mechanistic comparator.
• Multi-omics Analysis Reveals the Protection of a Quadruple Probiotic Mixture in Experimental Autoimmune Hepatitis
  Tests a multi-strain probiotic mixture as an alternative microbiota-based intervention for immune-mediated disease, allowing readers to compare the breadth-of-transfer (FMT) versus defined-strain (probiotic) approach to the same therapeutic goal.
• Mechanism of FODMAP Restriction on FGID Patients
  Examines FODMAP dietary restriction as a non-invasive microbiota-modulating strategy for functional GI disorders, offering a lower-intervention comparator to FMT for readers evaluating the risk-benefit spectrum of gut microbiome therapies.
• Sichuan dark tea with a medicine-food-homology formula synergistically alleviates alcohol-associated gut microbiota disturbance, liver steatosis and death in mice
  Investigates herbal tea formulation effects on alcohol-associated gut microbiota disturbance, paralleling FMT's goal of correcting dysbiosis but through a food-based rather than transplantation-based mechanism — useful for contrasting intervention philosophy.
• Eubacterium rectale Mitigates Inflammatory Bowel Disease via Modulation of Glutamine Metabolism Through the GLS2 and NF-κB Pathway
  Focuses on Eubacterium rectale — a commensal bacterium whose abundance is typically reduced in CDI-associated dysbiosis — providing single-organism mechanistic depth that complements FMT's community-level approach.