Faecal Microbiota Transplantation

The donor stool is processed under strict medical and laboratory standards and can be delivered to the recipient’s gut through several methods [2,3]: 

• Lower Gastrointestinal Routes:  Administration via colonoscopy or enema delivers the transplant directly to the colon. Colonoscopy is often considered superior to enemas for treating recurrent Clostridioides difficile infection. [4] 
• Upper Gastrointestinal Routes: Delivery can be achieved using a nasogastric or nasojejunal tube. 

What Conditions Can FMT Help Treat? 

FMT is a well-established treatment for some conditions and is being actively investigated for many others. 

1. Clostridioides difficile (C. difficile) Infection FMT is a highly effective and recommended treatment for recurrent C. difficile infection (rCDI), particularly for cases that do not respond to standard antibiotic therapy. [5] It has an impressive success rate, with studies reporting resolution of the infection in 83% and 100% of cases.6 The procedure works by restoring the normal balance of gut bacteria, which helps to suppress the overgrowth of C. difficile. [7] 
2. Inflammatory Bowel Disease (IBD) FMT is an emerging experimental treatment for IBD, including both Ulcerative Colitis (UC) and Crohn’s Disease (CD). [8,9] 
   • Ulcerative Colitis (UC): Multiple randomised controlled trials have shown that FMT can be effective in inducing clinical and endoscopic remission in patients with active UC. [10,11] Meta-analyses have confirmed a significant benefit compared to placebo, although efficacy can vary depending on the protocol used, such as the number of infusions and the use of multiple donors. [12, 13] 
   • Crohn’s Disease (CD): Research suggests that patients with CD may also benefit from FMT, with some studies showing a clinical remission rate of over 50%. [12,14] However, more large-scale controlled trials are needed to confirm these findings and establish standardised protocols. 
3. Irritable Bowel Syndrome (IBS) Evidence for using FMT to treat IBS is still developing, with studies yielding mixed results. [15] Some randomised trials have shown significant improvements in symptoms and quality of life, with effects lasting as long as three years post-transplant. [16] However, other meta-analyses have found insufficient evidence to recommend it as a standard treatment, [17] noting that the method of delivery may be important; for example, FMT delivered via colonoscopy or nasojejunal tube appeared more beneficial than capsules in some analyses. [18] 
4. Other Emerging Applications Research is expanding to explore FMT for a wide range of other conditions, although evidence remains preliminary: 
   • Parkinson’s Disease: Early open-label studies and a recent phase 2 trial have reported improvements in motor and non-motor symptoms (particularly constipation) following FMT, suggesting that targeting the gut microbiome may be a viable therapeutic strategy. [19] 
   • Metabolic Syndrome and Diabetes: Studies have shown that FMT can improve insulin sensitivity and other metabolic markers in patients with metabolic syndrome and type 1 or type 2 diabetes. [20] 
   • Cognitive and Mental Health Disorders: Pre-clinical studies and early clinical trials have suggested that altering the gut microbiota via FMT may influence cognitive function, with case reports showing improvements in patients with conditions like Alzheimer’s disease. [21] 

Donor Selection, Screening, and Stool Preparation 

You do not need to find your own donor. Patient safety is paramount, and donor material is sourced from regulated stool banks that follow strict national and international guidelines. [22, 23]

Donor Screening The selection process is meticulous to prevent the transmission of infectious diseases. Donors undergo a comprehensive screening process that includes: 

• A detailed review of their medical history and lifestyle. 
• Rigorous blood and stool testing to screen for a wide array of viral, bacterial, and parasitic pathogens. 

Stool Preparation Once a donor is approved, the donated stool is processed in a sterile laboratory environment.

• The material is homogenised, filtered, and prepared into the required form, such as a liquid solution for endoscopic delivery. 
• The preparation can be used fresh or, more commonly, is frozen and stored under controlled conditions until use. Frozen preparations have been shown to be effective and allow for the creation of extensively screened stool banks. [23] 

The FMT Procedure and Safety 

Patient Assessment

Before undergoing FMT, a gastroenterologist will conduct a thorough review of your medical history and previous treatments. Further tests may be required to assess your suitability, which can include: 

• Blood tests for infection screening and organ function. 

• Stool tests to check for existing infections. 

• Endoscopic procedures like a colonoscopy to evaluate the health of your bowel and screen for contraindications. 

Side Effects and Risks  

FMT is generally considered a safe procedure, when performed under medical supervision with properly screened donor material. 

• Common Side Effects: Most side effects are mild, temporary, and self-limiting. They most often include bloating, cramping, abdominal discomfort, and temporary changes in bowel habits. [24] 

• Serious Risks: Serious adverse events are rare. The most significant risk comes from the potential transmission of infectious agents, which is why rigorous donor screening is essential. [25] 

Is FMT Safe for Everyone?  

Numerous systematic reviews and meta-analyses across different conditions have established a strong safety profile for FMT. [4,8,10-13,15,17,20,24] One large analysis of over 5,000 patients found that significant adverse events directly related to FMT occurred in less than 1% of cases. [24] The most commonly reported side effects are mild, transient, and self-limiting gastrointestinal symptoms, such as abdominal pain, bloating, diarrhoea, nausea, and fever. [12,19] 

While generally safe, FMT may not be suitable for everyone. A specialist will assess your individual case. Particular caution may be required for individuals who:  

• Have a severely compromised immune system. [5,25] 

• Are pregnant or breastfeeding. [16] 

• Have certain other chronic health conditions. [12,24] 

Can I do DIY FMT at home? 

No. You should never attempt FMT at home using unscreened donor stool. Stool is a biological substance that can carry dangerous and potentially life-threatening infectious pathogens, even if the donor appears healthy. [25] For your safety, FMT must only be performed in a clinical setting using regulated, screened, and processed donor material. 

When will I know if it’s working? 

The time it takes to see benefits from FMT can vary. In cases of C. difficile infection, improvement is often rapid. For chronic conditions like IBD or IBS, it may take several weeks or even months to experience the full therapeutic effect. Clinical trials often assess primary outcomes at 8 to 12 weeks post-treatment. [12,16] 

Will my diet affect the results?  

Diet plays a crucial role in shaping and maintaining a healthy gut microbiome. After FMT, a high-fibre diet rich in whole foods is often recommended to support the newly established microbial community. Your gastroenterologist can provide personalised dietary advice to help sustain the benefits of the treatment. 

References 

1. Borody TJ, Paramsothy S, Agrawal G. Fecal microbiota transplantation: Indications, methods, evidence, and future directions. Curr Gastroenterol Rep. 2013;15(8):337. DOI: 10.1007/s11894-013-0337-1  
2. Choi HH, Cho YS. Fecal Microbiota Transplantation: Current Applications, Effectiveness, and Future Perspectives. Clin Endosc. 2016;49(3):257-65. DOI: 10.5946/ce.2015.117
3. Gulati M, Singh SK, Corrie L, Kaur IP, Chandwani L. Delivery routes for faecal microbiota transplants: available, anticipated and aspired. Pharmacol Res. 2020;159:104954. DOI: 10.1016/j.phrs.2020.104954 
4. Ramai D, Zakhia K, Fields PJ, Ofosu A, Patel G, Shahnazarian V, et al. Fecal Microbiota Transplantation (FMT) with colonoscopy is Superior to Enema and nasogastric tube while comparable to capsule for the treatment of recurrent Clostridioides difficile infection: a systematic review and meta-analysis. Dig Dis Sci. 2021;66(2):369-80. DOI: 10.1007/s10620-020-06185-7 
5. Cammarota G, Ianiro G, Tilg H, Rajilić-Stojanović M, Kump P, Satokari R, et al. European consensus conference on faecal microbiota transplantation in clinical practice. Gut. 2017;66(4):569-80. DOI: 10.1136/gutjnl-2016-313017  
6. Seekatz AM, Aas J, Gessert CE, et al. Recovery of the gut microbiome following fecal microbiota transplantation. mBio. 2014;5(3):e00893-14. Published 2014 Jun 17. DOI:10.1128/mBio.00893-14  
7. Khoruts A, Sadowsky MJ. Understanding the mechanisms of faecal microbiota transplantation. Nat Rev Gastroenterol Hepatol. 2016;13(9):508-16.  DOI: 10.1038/nrgastro.2016.98 
8. Tan XY, Xie YJ, Liu XL, Li XY, Jia B. A Systematic Review and Meta-Analysis of Randomized Controlled Trials of Fecal Microbiota Transplantation for the Treatment of Inflammatory Bowel Disease. Evid Based Complement Alternat Med. 2022;2022:8266793. DOI: 10.1155/2022/8266793 
9. Bakker GJ, Nieuwdorp M. Fecal microbiota transplantation: therapeutic potential for a multitude of diseases beyond Clostridium difficile. Microbiol Spectr. 2017;5(4). DOI: 10.1128/microbiolspec.BAD-0008-2017 
10. Feng J, Chen Y, Liu Y, et al. Efficacy and safety of fecal microbiota transplantation in the treatment of ulcerative colitis: a systematic review and meta-analysis. Sci Rep. 2023;13(1):14494. DOI: 10.1038/s41598-023-41182-6 
11. Colman RJ, Rubin DT. Fecal microbiota transplantation as therapy for inflammatory bowel disease: a systematic review and meta-analysis. J Crohns Colitis. 2014;8(12):1569-81. DOI: 10.1016/j.crohns.2014.08.006 
12. Paramsothy S, Paramsothy R, Rubin DT, Kamm MA, Kaakoush NO, Mitchell HM, et al. Faecal Microbiota Transplantation for Inflammatory Bowel Disease: A Systematic Review and Meta-analysis. J Crohns Colitis. 2017;11(10):1180-99.  
13. Caldeira LF, Borba HH, Tonin FS, Wiens A, Fernandez-Llimos F, Pontarolo R. Fecal microbiota transplantation in inflammatory bowel disease patients: a systematic review and meta-analysis. PLOS ONE. 2020;15(9):e0238910. DOI: 10.1093/ecco-jcc/jjx063 
14. Wang H, Cui B, Li Q, Ding X, Li P, et al. The Safety of Fecal Microbiota Transplantation for Crohn’s Disease: Findings from A Long-Term Study. Adv Ther. 2018;35(11):1935-44. DOI: 10.1007/s12325-018-0800-3 
15. Myneedu K, Deoker A, Schmulson MJ, Bashashati M. Fecal microbiota transplantation in irritable bowel syndrome: a systematic review and meta-analysis. United Eur Gastroenterol J. 2019;7(8):1033-41. DOI: 10.1177/2050640619866990 
16. El-Salhy M, Winkel R, Casen C, et al. Efficacy of Fecal Microbiota Transplantation for Patients With Irritable Bowel Syndrome at 3 Years After Transplantation. Gastroenterology. 2022;163(4):982-994.e6. DOI: 10.1053/j.gastro.2022.06.020 
17. Ianiro G, Eusebi LH, Black CJ, Gasbarrini A, Cammarota G, Ford AC. Systematic review with meta-analysis: efficacy of faecal microbiota transplantation for the treatment of irritable bowel syndrome. Aliment Pharmacol Ther. 2019;50(3):240-8. DOI: 10.1111/apt.15330
18. Johnsen PH, Hilpüsch F, Cavanagh JP, et al. Faecal microbiota transplantation versus placebo for moderate-to-severe irritable bowel syndrome: a double-blind, randomised, placebo-controlled, parallel-group, single-centre trial. Lancet Gastroenterol Hepatol. 2018;3(1):17-24. DOI: 10.1016/S2468-1253(17)30338-2 
19. Bruggeman A, Vandendriessche C, Hamerlinck H, et al. Safety and efficacy of faecal microbiota transplantation in patients with mild to moderate Parkinson’s disease (GUT-PARFECT): a double-blind, placebo-controlled, randomised, phase 2 trial. eClinicalMedicine. 2024;71:102563. DOI: 10.1016/j.eclinm.2024.102563 
20. Qiu B, Liang J, Li C. Effects of fecal microbiota transplantation in metabolic syndrome: A meta-analysis of randomized controlled trials. PLOS ONE. 2023;18(7):e0288718.DOI: 10.1371/journal.pone.0288718 
21. Park SH, Lee JH, Kim JS, et al. Fecal microbiota transplantation can improve cognition in patients with cognitive decline and Clostridioides difficile infection. Aging. 2022;14(16):6449-66.  DOI: 10.18632/aging.204230 
22. König J, Siebenhaar A, Högenauer C, Arkkila P, Nieuwdorp M, et al. Consensus report: faecal microbiota transfer – clinical applications and procedures. Aliment Pharmacol Ther. 2017;45(2):222-39. DOI: 10.1111/apt.13868 
23. Cammarota G, Ianiro G, Kelly CR, Mullish BH, Allegretti JR, et al. International consensus conference on stool banking for faecal microbiota transplantation in clinical practice. Gut. 2019;68(12):2111-21. DOI: 10.1136/gutjnl-2019-319548 
24. Marcella C, Cui B, Kelly CR, Ianiro G, Cammarota G, Zhang F. Systematic review: The global incidence of faecal microbiota transplantation-related adverse events from 2000 to 2020. Aliment Pharmacol Ther. 2021;53(1):33-42.  DOI: 10.1111/apt.16148 
25. Sandhu A, Chopra T. Fecal microbiota transplantation for recurrent Clostridioides difficile, safety, and pitfalls. Ther Adv Gastroenterol. 2021;14:17562848211053104. DOI: 10.1177/17562848211053105