A New Therapootic Tool – DIY Probiotics?
Clostridium difficile infection is a killer. It is estimated that it is currently responsible for over 14,000 deaths per year in the US, or about 40 per day.1 These deaths are predominantly in elderly patients admitted to hospital or nursing home care for other reasons, and incidence of infection and death rates have climbed sharply over the last 20 years.2 C. difficile is a gram-positive, cytotoxin producing anaerobic bacterium which mediates colonic tissue injury and severe inflammation in susceptible patients. Although it is commensal, overgrowth is often triggered by use of antibiotic therapy, and it is thought that the administration of antibiotics, by disrupting the endogenous gut flora, reduces the natural protective mechanisms present in the gut which should keep the population in check. Complicating matters is the emergence in recent years of virulent strains of C. difficile which are resistant to many antibiotics, making treatment difficult and often ineffective. Perhaps out of desperation, some imaginative treatments have been suggested, with Seal et al proposing in 1987 the administration of a non-toxic form of C. difficile to take up the ecological niche in the gut and exclude the toxic form.3 This approach is being developed for human use and has been successful in animal trials.
Another innovative and somewhat unpalatable approach being trialled is the use of faecal microbiota transplants (FMT), where the patient receives a stool from a healthy donor either via colonoscope or nasogastric tube. The stool is liquefied, filtered and mixed with sterile saline and then administered into the upper bowel.4 Usually the donor is a close relative and they are screened prior to donation in a similar fashion to blood donors, plus the stool is examined for pathogens. The first recorded use of human faecal transplantation in the literature goes back to 1958 and it has been steadily gaining interest, particularly in the last 5-10 years, due to the dramatic effectiveness it can have in some conditions.5 In a population of 166 patients with recurrent C. difficile infection resistant to all antibiotics, where the outcome would have been expected to be fatal in the majority of patients, use of FMT lead to cure in 87% of patients.6
The mechanism of action of FMT is unknown, however the leading theory behind FMT is that by using healthy donor stool, there is a replacement of a dysbiotic microbiota with a diverse range of microbes more consistent with bowel health. Some researchers have attempted to characterise the changes in the bowel flora before and after FMT and have shown a number of significant findings. Tvede observed an absence of Bacteroides while patients were symptomatic but were able to regularly culture Bacteroides following FMT.7 Gustafsson showed that stool short chain fatty acid (SCFA) levels were low in patient’s v’s healthy population, and that following FMT they returned to levels typical of a healthy population.8 So in effect it appears that FMT may be functioning as a probiotic and providing many of the benefits typically associated with probiotic therapy, such as reduction of pathogens, enhancement of SCFA synthesis and management of symptoms of gastrointestinal disease.
There is considerable evidence for a number of strains of probiotic organisms in the management of infectious and antibiotic induced diarrhoea. Saccharomyces boulardii and Lactobacillus rhamnosus GG (LGG) are two strains with a significant amount of evidence and have been shown to reduce infectious diarrhoea in travellers , inhibit C. difficile toxin A , reduce antibiotic associated diarrhoea and to be useful alongside standard treatment for C. difficile infection to reduce the relapse rate.9-12 It appears that in severe C. difficile infections, the efficacy of FMT is superior to that of probiotics, while in less severe cases and for a broad range of other GIT disorders, probiotics are well indicated.
FMT and Inflammatory Bowel Disorders
Another area where orthodox treatments appear to be of limited benefit is the management of inflammatory bowel disorders (IBD) such as ulcerative colitis, Crohn’s and Irritable Bowel Syndrome (IBS). Typically patients take a range of powerful anti-inflammatory and immunosuppressive agents to reduce the autoimmune mediated tissue inflammation within the gut wall. Professor Tom Borody is an Australian researcher whose group is the first to report success with the treatment of IBD using FMT. A recent review article by Anderson summarised some of Borody’s and other work in this area and found that of 41 IBD patients treated with FMT, the majority reported a reduction in symptoms (19/25), cessation of IBD medications (13/17) and disease remission (15/24).13 Whilst a small sample, these results are very impressive given the typically low rates of remission of these conditions with current mainstream treatment options.
An important difference observed by researchers between the treatment of C. difficile infection and IBD is that the former generally only requires a single FMT procedure for a lasting effect, whereas the treatment of IBD requires repeated administration of FMT on a monthly basis to achieve disease control. This raises the question of the mechanism of action of donor stool in IBD, and there are a number of theories and possibilities. It has been suggested that ulcerative colitis is caused by an as-yet undescribed pathogen, and the cell-mediated T-Helper 1/17 autoimmune response generated is triggered at least in part by the attempts of the immune system to eradicate this pathogen.14 At some point in the process the immune system then begins to target the tissues of the gut, perhaps as a result of molecular mimicry between the pathogen and the tissues of the gut. Genome Wide Association Studies (GWAS) have identified a number of genetic risk loci that are associated with IBD. A significant number of these relate to genes that are involved in the identification of gut microbes, such as Toll-like receptors, or genes that are related to the production of anti-microbial peptides by the cells of the gut. In animals and people with mutations in some of these key genes reducing the ability of the gut to select and defend against certain microbes, there is a significantly increased risk of developing IBD.15 Twin studies also strongly suggest that there is an environmental component to the aetiology of IBD , which adds weight to the theory that IBD is caused by a pathogen.16
A second possible mechanism of action of FMT in IBD is an interaction between the gut flora and the immune system, which either drives or reduces inflammatory signalling. This may still fit within the pathogen model, but it is a more nuanced appreciation of the regulation of gut flora that takes place by the host, and in turn the programming and development of the immune system of the host that is mediated by the gut flora. Humans have been described as a meta-organism, comprised of many different species which all work cooperatively to provide a healthy and harmonious outcome. A key finding of the recently completed Human Microbiome Project was that the number of human cells in our body is outnumbered by a factor of 10 to the number of microbial cells, and that of all the genes expressing in the human body, only about 1% are human. With this in mind, the microbiome has been described as the ‘majority shareholder’ in the body, and as such has a very significant impact on health outcomes.17 We may therefore need to rethink our relationship with our bugs from one of potential pathogens that should be eradicated to make the body as sterile as is possible, to a relationship of mutual benefit and respect, where we provide a home and food for the bugs, and they provide us with many beneficial functions, including protection against pathogens, synthesis of nutrients, detoxification of waste and synthesis of butyrate to feed our colonocytes. A very important observation is that loss of microbial diversity is one of the key associations with IBD, and rather than there being too many bacteria in the gut of people with IBD, they tend to have a lower number, and significantly lower species variation than healthy individuals.18,19 It is speculated that exposure to factors which reduce microbiome diversity such as antibiotics and western diet may be predisposing factors in the development of IBD, and that strategies aimed at restoring the microbial diversity may represent a novel therapy for combating chronic inflammatory conditions both within the gut and systemically.20
One of the key species that has been shown to reduce inflammation within the gut and to help manage some of the symptoms of IBD is Lactobacillus plantarum, which has been shown to actively block NF-kB signalling.21 L. plantarum secretes a substance which down-regulates NF-kB via the TNF receptor, supporting the idea that supplementation with this probiotic organism may help to restore some of this ecological variation which keeps inflammation within the gut in balance. L. plantarum has also been shown to enhance tight junction integrity, potentially reducing the problems associated with ‘leaky gut syndrome’.22
Grow Healthy Bugs
The broad range of science supporting a number of specific strains of probiotics, combined with the emerging science of FMT, contribute to the overall conclusion that bacteriotherapy has a very important role to play in diseases of the gut. Research is also emerging of the role human microbiota play in many other conditions, including diabetes, allergy, obesity and even neurodevelopmental disorders (see Figure 1).23 However, the provision of bacteria that support microbial diversity is not sufficient; we also need to provide the correct terrain or soil for these bacteria to grow in. This underlines the importance of a diet high in soluble fibre, plant based fibres and fermented foods. It also suggests that we should avoid foods known to create dysbiosis, such as refined sugars, grains and heavily processed commercial foods. In addition, avoidance of antibiotics and foods with a high chemical and antibiotic residue is advisable if possible. Finally, basic digestive hygiene such as chewing effectively, regular bowel function, eating while relaxed and supporting the production of gastric acid, digestive enzymes and bile through herbs and digestive enzymes is also very important. The combination of creating the correct environment within the gut combined with the provision of selected probiotics, or in severe cases FMT, may be one of the most important therapeutic tools available for many conditions.
FIGURE 1. Some of the known contributions of intestinal microbiota to host health. Changes in the microbial community have been linked to alterations in host physiology and immune responses that affect both local and extraintestinal sites.24
 http://www.cdc.gov/vitalsigns/hai/  Kelly CP, LaMont JT. Clostridium difficile—more difficult than ever. N Engl J Med. 2008;359:1932–1940.  Seal D, Borriello SP, Barclay F, Welch A, Piper M, Bonnycastle M. Treatment of relapsing Clostridium difficile diarrhoea by administration of a non-toxigenic strain. Eur J Clin Microbiol 1987;6:51-3.  Landy j et al. Review article: faecal transplantation therapy for gastrointestinal disease. Aliment Pharmacol Ther 2011; 34: 409-415  Eiseman B, Silen W, Bascom GS, et al. Fecal enema as an adjunct in the treatment of pseudomembranous enterocolitis. Surgery. 1958;44:854–859.  Landy j et al. Review article: faecal transplantation therapy for gastrointestinal disease. Aliment Pharmacol Ther 2011; 34: 409-415  Tvede M, Rask-Madsen J. Bacteriotherapy for chronic relapsing Clostridium difficile diarrhoea in six patients. Lancet 1989; 1: 1156–60.  Gustaffson A, Lund-Tonnesen S, Berstad A, et al. Faecal short-chain fatty acids in patients with antibiotic-associated diarrhoea, before and after faecal enema treatment. Scand J Gastroenterol 1998; 33: 721–7.  Kirchhelle A, Fruhwein N, Toburen D. Treatment of persistent diarrhoea with S. boulardii in returning travellers. Results of a prospective study. Fortsch Med 1996; 114(11): 136-140.  Jahn HU, Ulrich R, Schneider T, Liehr RM, Schieferdecker HL, Holst H, Zeitz M. Immunological and trophical effects of Saccharomyces boulardii on the small intestine in healthy human volunteers. Digestion 1996; 57(2): 95-104.  Arvola T, Laiho K, Torkkeli S, Mykkänen H, Salminen S, Maunula L, Isolauri E. Prophylactic Lactobacillus GG reduces antibiotic-associated diarrhoea in children with respiratory infections: a randomized study. Pediatrics 1999 Nov;104(5):e64.  Surawicz CM, McFarland LV, Greenberg RN, Rubin M, Fekety R, Mulligan ME, Garcia RJ, Brandmarker S, Bowen K, Borjal D, Elmer GW. The search for a better treatment for recurrent Clostridium difficile disease: use of high-dose vancomycin combined with Saccharomyces boulardii. Clin Infect Dis 2000;31(4):1012-7.  Anderson et al. Systematic review: faecal microbiota transplantation in the management of inflammatory bowel diease. Aliment Pharmacol Ther 2012; 36: 503-516.  Nagalingam NA, Lynch SV. Role of the Microbiota in Inflammatory Bowel Diseases. Inflamm Bowel Dis 18;5 May 2012: 968-980.  Cadwell K, Liu JY, Brown SL. A key role for autophagy and the autophagy gene Atg16l1 in mouse and human intestinal Paneth cells. Nature. 2008;456:259–263.  Spehlmann ME, Begun AZ, Burghardt J. Epidemiology of inflammatory bowel disease in a German twin cohort: results of a nationwide study. Inflamm Bowel Dis. 2008;14:968–976.  Roberfroid M, et al. Prebiotic effects: metabolic and health benefits. Br J Nutr. 2010 Aug;104 Suppl 2:S1-63.  Walker AW, Sanders JD, Churcher C. High-throughput clone library analysis of the mucosa-associated microbiota reveals dysbiosis and differences between inflamed and non-inflamed regions of the intestine in inflammatory bowel disease. BMC Microbiol. 2011;10:11–17.  Frank DN, Robertson CE, Hamm CM. Disease phenotype and genotype are associated with shifts in intestinal-associated microbiota in inflammatory bowel diseases. Inflamm Bowel Dis. 2011;17:179–184.  Nagalingam NA, Lynch SV. Role of the Microbiota in Inflammatory Bowel Diseases. Inflamm Bowel Dis 18;5 May 2012: 968-980.  Petrof E, Claud E, Sun J. Bacteria-free solution derived from Lactobacillus plantarum inhibits multiple NF-kappaB pathways and inhibits proteasome function. Inflamm Bowel Dis. 2009;15:1537–1547.  Anderson RC, Cookson AL, McNabb WC. Lactobacillus plantarum MB452 enhances the function of the intestinal barrier by increasing the expression levels of genes involved in tight junction formation. BMC Microbiol. 2010;10:316.  Nagalingam NA, Lynch SV. Role of the Microbiota in Inflammatory Bowel Diseases. Inflamm Bowel Dis 18;5 May 2012: 968-980.
 Nagalingam NA, Lynch SV. Role of the Microbiota in Inflammatory Bowel Diseases. Inflamm Bowel Dis 18;5 May 2012: 968-980.