Rectal bacteriotherapy for recurrent Clostridium difficile-associated diarrhoea: results from a case series of 55 patients in Denmark 2000–2012

Gut Microbiome Transplants and Their Health Impacts across Species

The human gut, required for ingesting and processing food, extracting nutrients, and excreting waste, is made up of not just human tissue but also trillions of microbes that are responsible for many health-promoting functions. However, this gut microbiome is also associated with multiple diseases and negative health outcomes, many of which do not have a cure or treatment. One potential mechanism to alleviate these negative health effects caused by the microbiome is the use of microbiome transplants. Here, we briefly review the gut's functional relationships in laboratory model systems and humans, with a focus on the different diseases they directly affect. We then provide an overview of the history of microbiome transplants and their use in multiple diseases including Alzheimer's disease, Parkinson's disease, as well as Clostridioides difficile infections, and irritable bowel syndrome. We finally provide insights into areas of research in which microbiome transplant research is lacking, but that simultaneously may provide significant health improvements, including age-related neurodegenerative diseases.

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.

Fecal microbiota transplantation: a review on current formulations in Clostridioides difficile infection and future outlooks

INTRODUCTION

The role of the gut microbiota in health and the pathogenesis of several diseases has been highlighted in recent years. Even though the precise mechanisms involving the microbiome in these ailments are still unclear, microbiota-modulating therapies have been developed. Fecal microbiota transplantation (FMT) has shown significant results against Clostridioides difficile infection (CDI), and its potential has been investigated for other diseases. Unfortunately, the technical aspects of the treatment make it difficult to implement. Pharmaceutical technology approaches to encapsulate microorganisms could play an important role in providing this treatment and render the treatment modalities easier to handle.

AREAS COVERED

After an overview of CDI, this narrative review aims to discuss the current formulations for FMT and specifically addresses the technical aspects of the treatment. This review also distinguishes itself by focusing on the hurdles and emphasizing the possible improvements using pharmaceutical technologies.

EXPERT OPINION

FMT is an efficient treatment for recurrent CDI. However, its standardization is overlooked. The approach of industrial and hospital preparations of FMT are different, but both show promise in their respective methodologies. Novel FMT formulations could enable further research on dysbiotic diseases in the future.

The Age of Next-Generation Therapeutic-Microbe Discovery: Exploiting Microbe-Microbe and Host-Microbe Interactions for Disease Prevention

Humans are considered "superorganisms," harboring a diverse microbial collective that outnumbers human cells 10 to 1. Complex and gravely understudied host- and microbe-microbe interactions-the product of millions of years of host-microbe coevolution-govern the superorganism in almost every aspect of life functions and overall well-being. Abruptly disrupting these interactions via extrinsic factors has undesirable consequences for the host. On the other hand, supplementing commensal or beneficial microbes may mitigate perturbed interactions or enhance the interactive relationships that ultimately benefit all parties. Hence, immense efforts have focused on dissecting the innumerable host- and microbe-microbe relationships to characterize if a "positive" or "negative" interaction is at play and to exploit such behavior for broader implications. For example, microbiome research has worked to identify and isolate naturally antipathogenic microbes that may offer therapeutic potential either in a direct, one-on-one application or by leveraging its unique metabolic properties. However, the discovery and isolation of such desired therapeutic microbes from complex microbiota have proven challenging. Currently, there is no conventional technique to universally and functionally screen for these microbes. With this said, we first describe in this review the historical (probiotics) and current (fecal microbiota or defined consortia) perspectives on therapeutic microbes, present the discoveries of therapeutic microbes through exploiting microbe-microbe and host-microbe interactions, and detail our team's efforts in discovering therapeutic microbes via our novel microbiome screening platform. We conclude this minireview by briefly discussing challenges and possible solutions with therapeutic microbes' applications and paths ahead for discovery.

Long-Term Safety Following Faecal Microbiota Transplantation as a Treatment for Recurrent Clostridioides difficile Infection Compared with Patients Treated with a Fixed Bacterial Mixture: Results from a Retrospective Cohort Study

Faecal microbiota transplantation (FMT) is the recommended treatment for recurrent C. difficile infection (rCDI) following a second recurrence. FMT is considered safe in the short term when procedures for the screening of donors and transferred material are followed. However, the long-term safety profile of FMT treatment is largely unknown. In a retrospective cohort study, we assessed the long-term safety of patients treated for rCDI with FMT or a fixed bacterial mixture, rectal bacteriotherapy (RBT). The overall survival, risk of hospital admission, onset of certain pre-specified diseases (cancer, diabetes mellitus, hypertension and inflammatory bowel disease) and risk of being diagnosed with a multidrug-resistant organism were assessed by undertaking a review of the treated patients’ medical records for up to five years following treatment. A total of 280 patients were treated for rCDI with FMT (n = 145) or RBT (n = 135) between 2016 and 2020. In the five years following treatment, there were no differences in survival (adjusted hazard ratio (aHR) 1.03; 95% CI 0.68–1.56), p = 0.89), risk of hospital admission ((aHR 0.92; 95% CI 0.72–1.18), p = 0.5) or onset of any of the analysed diseases. In conclusion, FMT was not associated with increased mortality, risk of hospital admission or onset of disease following treatment when compared with RBT.

Fecal microbiota transplantation and Clostridioides difficile infection among privately insured patients in the United States

BACKGROUND

Clostridioides difficile infection (CDI) may be rising in severity in the US over the past decade and its treatment landscape is changing given the recent adoption of fecal microbiota transplantation (FMT) METHODS: We built a retrospective observational cohort using a database of a national care-plan containing medical claims of over 50 million individuals between 2008 and 2019. We used International Classification of Disease (ICD) and prescription data to identify patients with CDI. We estimated trends in disease burden and FMT use, and evaluated complications post FMT using a phenome-wide association approach.

RESULTS

We identified 38,396 patients with CDI; the median age was 60 years (IQR 45-74) and 60% were female (n = 23,374). The rate of CDI increased from 33.4 to 69.46 cases per 100,000 person-years between 2008 and 2015, and stabilized from 2015 to 2019 (increase of 4.77 cases per 100,000 person-years per year, 95% CI 3.55-5.98 prior to 2015 vs. 2.01 95% CI - 10.16 to 14.18 after 2015). Of the 7715 patients with recurrent CDI, 407 patients (5%) underwent FMT. Gastrointestinal complications were increased within 1 month post FMT (OR 99.60, p < 0.001). Sepsis was identified in two individuals (0.49% 95% CI 0.05-1.7%) within the first month post FMT. The risk of CDI recurrence significantly decreased post FMT compared with anti-CDI antibiotics in the multivariable model (raw-recurrence rate 9.8% vs 36%, aOR = 0.21, 95% CI 0.12-0.53, p < 0.001).

CONCLUSION

We show that FMT is strongly associated with a decrease in CDI recurrence compared with the usual care with generally mild complications for up to 2 years.

Danish national guideline for the treatment of Clostridioides difficile infection and use of faecal microbiota transplantation (FMT)

Aim: This Danish national guideline describes the treatment of adult patients with Clostridioides (formerly Clostridium) difficile (CD) infection and the use of faecal microbiota transplantation (FMT). It suggests minimum standard for implementing an FMT service.Method: Four scientific societies appointed members for a working group which conducted a systematic literature review and agreed on the text and recommendations. All clinical recommendations were evalluated for evidence level and grade of recommendation.Results: In CD infection, the use of marketed and experimental antibiotics as well as microbiota-based therapies including FMT are described. An algorithm for evaluating treatment effect is suggested. The organisation of FMT, donor recruitment and screening, laboratory preparation, clinical application and follow-up are described.Conclusion: Updated evidence for the treatment of CD infection and the use of FMT is provided.

Faecalibacterium prausnitzii increases following fecal microbiota transplantation in recurrent Clostridioides difficile infection

OBJECTIVE

Fecal microbiota transplantation (FMT) is a highly effective treatment for Clostridioides difficile infection (CDI). However, the fecal transplant's causal components translating into clearance of the CDI are yet to be identified. The commensal bacteria Faecalibacterium prausnitzii may be of great interest in this context, since it is one of the most common species of the healthy gut microbiota and produces metabolites with anti-inflammatory properties. Although there is mounting evidence that F. prausnitzii is an important regulator of intestinal homeostasis, data about its role in CDI and FMT are relatively scarce.

METHODS

Stool samples from patients with recurrent CDI were collected to investigate the relative abundance of F. prausnitzii before and after FMT. Twenty-one patients provided fecal samples before the FMT procedure, at 2 weeks post-FMT, and at 2-4 months post-FMT. The relative abundance of F. prausnitzii was determined using quantitative polymerase chain reaction.

RESULTS

The abundance of F. prausnitzii was elevated in samples (N = 9) from donors compared to pre-FMT samples (N = 15) from patients (adjusted P<0.001). No significant difference in the abundance of F. prausnitzii between responders (N = 11) and non-responders (N = 4) was found before FMT (P = 0.85). In patients with CDI, the abundance of F. prausnitzii significantly increased in the 2 weeks post-FMT samples (N = 14) compared to the pre-FMT samples (N = 15, adjusted P<0.001). The increase persisted 2-4 months post-FMT (N = 15) compared to pre-FMT samples (N = 15) (adjusted P<0.001).

CONCLUSIONS

FMT increases the relative abundance of F. prausnitzii in patients with recurrent CDI, and this microbial shift remains several months later. The baseline abundance of F. prausnitzii in donors or recipients was not associated with future treatment response, although a true predictive capacity cannot be excluded because of the limited sample size. Further studies are needed to discern whether F. prausnitzii plays an active role in the resolution of CDI.

Knowledge, attitudes, ethical and social perspectives towards fecal microbiota transplantation (FMT) among Jordanian healthcare providers

BACKGROUND

Fecal microbiota transplant (FMT) is a treatment modality that involves the introduction of stool from a healthy pre-screened donor into the gastrointestinal tract of a patient. It exerts its therapeutic effects by remodeling the gut microbiota and treating microbial dysbiosis-imbalance. FMT is not regulated in Jordan, and regulatory effort for FMT therapy in Jordan, an Islamic conservative country, might be faced with unique cultural, social, religious, and ethical challenges. We aimed to assess knowledge, attitudes, and perceptions of ethical and social issues of FMT use among Jordanian healthcare professionals.

METHODS

An observational, cross-sectional study design was used to assess knowledge, attitudes, and perceptions of ethical and social issues of FMT among 300 Jordanian healthcare professionals.

RESULTS

A large proportion (39 %) thought that the safety and efficacy of this technique are limited and 29.3 % thought there is no evidence to support its use. Almost all (95 %) responded that they would only perform it in certain cases, if ethically justified, and 48.3 % would use it due to treatment failure of other approaches. When reporting about reasons for not using it, 40 % reported that they would not perform it due to concerns about medical litigation, fear of infections (38 %), and lack of knowledge of long safety and efficacy (31.3 %). Interestingly, all practitioners said they would perform this procedure through the lower rather than upper gastrointestinal tract modality and the majority will protect the patient's confidentiality via double-blinding (43.3 %). For a subset of participants (n = 100), the cultural constraints that might affect the choice of performing FMT were mainly due to donor's religion, followed by dietary intake, and alcohol consumption.

CONCLUSIONS

Our healthcare practitioners are generally reluctant to use the FMT modality due to religious and ethical reasons but would consider it if there was a failure of other treatment and after taking into consideration many legislative, social, ethical and practice-based challenges including safety, efficacy and absence of guidelines.

Microbiota-mediated protection against antibiotic-resistant pathogens

Colonization by the microbiota provides one of our most effective barriers against infection by pathogenic microbes. The microbiota protects against infection by priming immune defenses, by metabolic exclusion of pathogens from their preferred niches, and through direct antimicrobial antagonism. Disruption of the microbiota, especially by antibiotics, is a major risk factor for bacterial pathogen colonization. Restoration of the microbiota through microbiota transplantation has been shown to be an effective way to reduce pathogen burden in the intestine but comes with a number of drawbacks, including the possibility of transferring other pathogens into the host, lack of standardization, and potential disruption to host metabolism. More refined methods to exploit the power of the microbiota would allow us to utilize its protective power without the drawbacks of fecal microbiota transplantation. To achieve this requires detailed understanding of which members of the microbiota protect against specific pathogens and the mechanistic basis for their effects. In this review, we will discuss the clinical and experimental evidence that has begun to reveal which members of the microbiota protect against some of the most troublesome antibiotic-resistant pathogens: Klebsiella pneumoniae, vancomycin-resistant enterococci, and Clostridioides difficile.

Alterations in the intestinal microbiome associated with PCOS affect the clinical phenotype

Polycystic ovarian syndrome (PCOS), characterized by chronic anovulation and hyperandrogenaemia, is a complex endocrine and metabolic disorder commonly seen in women of reproductive age. Multiple factors, including the intestinal microbiome, affect the pathogenesis and development of PCOS. However, the specific mechanisms by which gut microbes play a role in PCOS remain elusive. This review summarizes recent research about the transformational changes in gut microbes revealed in PCOS patients and the possible mechanisms and pathways by which the intestinal microbiome exerts influence on PCOS progression and phenotypes. In addition to the intestinal microbiome, evidence from animal studies suggests changes in the vaginal microbiome under PCOS conditions. The alteration of microbiome could affect oestrus cycle and PCOS phenotypes. Microbiome is closely associated with medicine and therapeutic approaches. Microbiome influences drug and therapy response and itself is a new source of therapy. Accurate modulation of the intestinal and vaginal microbiome is a potential therapy for PCOS patients. Future studies are required to elucidate the specific role of each particular genera of microbiota and the mechanism by which microbiome impacts the pathogenesis, progression and phenotypes of PCOS.

Metagenomic and culturomic analysis of gut microbiota dysbiosis during Clostridium difficile infection

Recently, cocktail of bacteria were proposed in order to treat Clostridium difficile infection (CDI), but these bacteriotherapies were selected more by chance than experimentation. We propose to comprehensively explore the gut microbiota of patients with CDI compared to healthy donors in order to propose a consortium of bacteria for treating C. difficile. We compared stool samples composition from 11 CDI patients and 8 healthy donors using two techniques: metagenomics, 16S V3-V4 region amplification and sequencing and culturomics, high throughout culture using six culture conditions and MALDI-TOF identification. By culturomics, we detected 170 different species in the CDI group and 275 in the control group. Bacteroidetes were significantly underrepresented in the CDI group (p = 0.007). By metagenomics, 452 different operational taxonomic units assigned to the species level were detected in the CDI group compared to 522 in the control group. By these two techniques, we selected 37 bacteria only found in control group in more than 75% of the samples and/or with high relative abundance, 10 of which have already been tested in published bacteriotherapies against CDI, and 3 of which (Bifidobacterium adolescentis, Bifidobacterium longum and Bacteroides ovatus) have been detected by these two techniques. This controlled number of bacteria could be administrated orally in a non-invasive way in order to treat CDI.

Banking feces: a new frontier for public blood banks?

Fecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridioides difficile infection and is potentially beneficial in other microbiota-related disorders. The provision of FMT in routine clinical practice requires an extensive infrastructure that is reliant on voluntary donors. Alongside an increasing demand for FMT, the logistic barriers of a large-scale donor-dependent operation and the difficulties among health authorities to regulate FMT limit the dissemination of sustainable FMT services. Blood centers are large organizations that handle a multitude of donor-dependent operations on a daily basis. Blood and feces share many of the same dependencies, and feces may present a new opportunity for the blood services to handle. In this paper, we describe how an FMT service may be established and embedded within the blood service infrastructure, and we explain the benefits of using blood donors as feces donors. We further explore the current indications of FMT, the challenges related to the lack of legislation, and the future perspectives for blood banks to meet a new and increasing demand.

Problems with the concept of gut microbiota dysbiosis

The human microbiome research is with the notable exception of fecal transplantation still mostly in a descriptive phase. Part of the difficulty for translating research into medical interventions is due to the large compositional complexity of the microbiome resulting in datasets that need sophisticated statistical methods for their analysis and do not lend to industrial applications. Another part of the difficulty might be due to logical flaws in terminology particularly concerning ‘dysbiosis’ that avoids circular conclusions and is based on sound ecological and evolutionary reasoning. Many case–control studies are underpowered necessitating more meta‐analyses that sort out consistent from spurious dysbiosis–disease associations. We also need for the microbiome a transition from statistical associations to causal relationships with diseases that fulfil a set of modified Koch's postulates for commensals. Disturbingly, the most sophisticated statistical analyses explain only a small percentage of the variance in the microbiome. Microbe–microbe interactions irrelevant to the host and stochastic processes might play a greater role than anticipated. To satisfy the concept of Karl Popper about conjectures and refutations in the scientific process, we should also conduct more experiments that try to refute the role of the commensal gut microbiota for human health and disease.

Efficacy of Routine Fecal Microbiota Transplantation for Treatment of Recurrent Clostridium difficile Infection: A Retrospective Cohort Study

Background

Patients with recurrent Clostridium difficile infections (CDIs) constitute an increasing treatment problem. Fecal microbiota transplantation (FMT) has shown promising results of treating recurrent CDI, where treatment with antibiotics fails repeatedly. Our study describes retrospective cohort treated with FMT at two major hospitals in Stockholm.

Methods

Medical records of all patients with recurrent CDI treated with FMT during the period 2013–2017 were reviewed. We evaluated cure of CDI-related diarrhea without relapse 10 weeks after FMT.

Results

47 patients were included. One treatment cured 25 patients (53%), and more than one treatment cured 32 patients (68%). Treatment outcome did not vary significantly with treatment with fresh donor feces or frozen fecal culture, days of use of antibiotics or days of hospitalization prior to CDI, and renal function or time from the first CDI to therapy. Treatment failure was associated with a significantly lower Karnofsky performance status score (70 points vs 90, p=0.02).

Conclusion

Fecal instillation, for the treatment of relapsing CDI, is a promising approach, with 68% success rate reported in this study. The success rate of FMT is high, regardless of multiple comorbidities, extended use of antibiotics, or long time hospitalization. Although generally FMT is performed with fresh donor feces, our data show that the usage of frozen fecal culture could be an effective treatment alternative in recurrent CDI.

The Microbiome and Its Potential for Pharmacology

The human microbiota (the microscopic organisms that inhabit us) and microbiome (their genes) hold considerable potential for improving pharmacological practice. Recent advances in multi-"omics" techniques have dramatically improved our understanding of the constituents of the microbiome and their functions. The implications of this research for human health, including microbiome links to obesity, drug metabolism, neurological diseases, cancer, and many other health conditions, have sparked considerable interest in exploiting the microbiome for targeted therapeutics. Links between microbial pathways and disease states further highlight a rich potential for companion diagnostics and precision medicine approaches. For example, the success of fecal microbiota transplantation to treat Clostridium difficile infection has already started to redefine standard of care with a microbiome-directed therapy. In this review we briefly discuss the nature of human microbial ecosystems and with pathologies and biological processes linked to the microbiome. We then review emerging computational metagenomic, metabolomic, and wet lab techniques researchers are using today to learn about the roles host-microbial interactions have with respect to pharmacological purposes and vice versa. Finally, we describe how drugs affect the microbiome, how the microbiome can impact drug response in different people, and the potential of the microbiome itself as a source of new therapeutics.

Case series of successful treatment with fecal microbiota transplant (FMT) oral capsules mixed from multiple donors even in patients previously treated with FMT enemas for recurrent Clostridium difficile infection

RATIONALE

Studies have shown that fecal microbiota transplantation (FMT) is a safe and highly efficient treatment for recurrent Clostridium difficile infection (rCDI). However, it is still unknown if one versus multiple donors or enemas versus capsule FMT are most efficient.

PATIENT CONCERNS

10 patients with at least 3 previous episodes of CDI were offered treatment with FMT capsules. 9 patients decided to participate.

DIAGNOSES

In this study, we treated 9 patients (25-86 years) with rCDI.

INTERVENTIONS

From October to November 2016, a total of 9 patients with recurrent CDI were treated with oral fecal microbiota capsules, with mixed donor feces from 4 donors with high microbiota diversity. All patients received treatment with vancomycin prior to the capsule regime.

OUTCOME

Patients had previous recurrences ranging from 2 to 10 recurrences. All 9 patients were successfully treated without recurrence after 180 days follow-up, even 2 patients previously treated with FMT enemas.

LESSONS

FMT capsules based on multiple donors are highly efficient in patients with rCDI.

Culturing the human microbiota and culturomics

The gut microbiota has an important role in the maintenance of human health and in disease pathogenesis. This importance was realized through the advent of omics technologies and their application to improve our knowledge of the gut microbial ecosystem. In particular, the use of metagenomics has revealed the diversity of the gut microbiota, but it has also highlighted that the majority of bacteria in the gut remain uncultured. Culturomics was developed to culture and identify unknown bacteria that inhabit the human gut as a part of the rebirth of culture techniques in microbiology. Consisting of multiple culture conditions combined with the rapid identification of bacteria, the culturomic approach has enabled the culture of hundreds of new microorganisms that are associated with humans, providing exciting new perspectives on host-bacteria relationships. In this Review, we discuss why and how culturomics was developed. We describe how culturomics has extended our understanding of bacterial diversity and then explore how culturomics can be applied to the study of the human microbiota and the potential implications for human health.

Microbiota-Based Therapies for Clostridium difficile and Antibiotic-Resistant Enteric Infections

Bacterial pathogens are increasingly antibiotic resistant, and development of clinically effective antibiotics is lagging. Curing infections increasingly requires antimicrobials that are broader spectrum, more toxic, and more expensive, and mortality attributable to antibiotic-resistant pathogens is rising. The commensal microbiota, comprising microbes that colonize the mammalian gastrointestinal tract, can provide high levels of resistance to infection, and the contributions of specific bacterial species to resistance are being discovered and characterized. Microbiota-mediated mechanisms of colonization resistance and pathogen clearance include bactericidal activity, nutrient depletion, immune activation, and manipulation of the gut's chemical environment. Current research is focusing on development of microbiota-based therapies to reduce intestinal colonization with antibiotic-resistant pathogens, with the goal of reducing pathogen transmission and systemic dissemination.

Cooperating Commensals Restore Colonization Resistance to Vancomycin-Resistant Enterococcus faecium

Antibiotic-mediated microbiota destruction and the consequent loss of colonization resistance can result in intestinal domination with vancomycin-resistant Enterococcus (VRE), leading to bloodstream infection in hospitalized patients. Clearance of VRE remains a challenging goal that, if achieved, would reduce systemic VRE infections and patient-to-patient transmission. Although obligate anaerobic commensal bacteria have been associated with colonization resistance to VRE, the specific bacterial species involved remain undefined. Herein, we demonstrate that a precisely defined consortium of commensal bacteria containing the Clostridium cluster XIVa species Blautia producta and Clostridium bolteae restores colonization resistance against VRE and clears VRE from the intestines of mice. While C. bolteae did not directly mediate VRE clearance, it enabled intestinal colonization with B. producta, which directly inhibited VRE growth. These findings suggest that therapeutic or prophylactic administration of defined bacterial consortia to individuals with compromised microbiota composition may reduce inter-patient transmission and intra-patient dissemination of highly antibiotic-resistant pathogens.

Efficacy of Sterile Fecal Filtrate Transfer for Treating Patients With Clostridium difficile Infection

BACKGROUND & AIMS

Fecal microbiota transplantation (FMT) is a highly effective therapy for recurrent Clostridium difficile infection (CDI). However, transferring undefined living bacteria entails uncontrollable risks for infectious and metabolic or malignant diseases, particularly in immunocompromised patients. We investigated whether sterile fecal filtrates (containing bacterial debris, proteins, antimicrobial compounds, metabolic products, and oligonucleotides/DNA), rather than intact microorganisms, are effective in patients with CDI.

METHODS

We performed a clinical case series to investigate the effects of fecal filtrate transfer (FFT) in 5 patients with symptomatic chronic-relapsing CDI at the Department of Internal Medicine I at the University Hospital Schleswig-Holstein (Kiel, Germany). Patients were followed up for at least 6 months and for up to 33 months. Stool was collected from 5 donors selected by the patients, and fully characterized according to FMT standards. Stool was sterile-filtered to remove small particles and bacteria; the filtrate was transferred to patients in a single administration via nasojejunal tube. Fecal samples were collected from patients before and at 1 week and 6 weeks after FFT. Microbiome, virome, and proteome profiles of donors and patients were compared.

RESULTS

In all 5 patients, FFT restored normal stool habits and eliminated symptoms of CDI for a minimum period of 6 months. Proteome analyses of selected FFT filtrates showed no obvious protein candidates associated with therapeutic efficacy. 16S ribosomal RNA gene sequencing detected diverse bacterial DNA signatures in the filtrates. Analysis of virus-like particles from a filtrate found to reduce symptoms of CDI showed a complex signature of bacteriophages. Bacterial phylogeny and virome profile analyses of fecal samples from recipients indicated longitudinal changes in microbial and viral community structures after FFT.

CONCLUSIONS

A preliminary investigation of 5 patients with CDI shows that transfer of sterile filtrates from donor stool (FFT), rather than fecal microbiota, can be sufficient to restore normal stool habits and eliminate symptoms. This finding indicates that bacterial components, metabolites, or bacteriophages mediate many of the effects of FMT, and that FFT might be an alternative approach, particularly for immunocompromised patients.

Clostridium difficile infection

Infection of the colon with the Gram-positive bacterium Clostridium difficile is potentially life threatening, especially in elderly people and in patients who have dysbiosis of the gut microbiota following antimicrobial drug exposure. C. difficile is the leading cause of health-care-associated infective diarrhoea. The life cycle of C. difficile is influenced by antimicrobial agents, the host immune system, and the host microbiota and its associated metabolites. The primary mediators of inflammation in C. difficile infection (CDI) are large clostridial toxins, toxin A (TcdA) and toxin B (TcdB), and, in some bacterial strains, the binary toxin CDT. The toxins trigger a complex cascade of host cellular responses to cause diarrhoea, inflammation and tissue necrosis - the major symptoms of CDI. The factors responsible for the epidemic of some C. difficile strains are poorly understood. Recurrent infections are common and can be debilitating. Toxin detection for diagnosis is important for accurate epidemiological study, and for optimal management and prevention strategies. Infections are commonly treated with specific antimicrobial agents, but faecal microbiota transplants have shown promise for recurrent infections. Future biotherapies for C. difficile infections are likely to involve defined combinations of key gut microbiota.

Gut Microbiota Dysbiosis as Risk and Premorbid Factors of IBD and IBS Along the Childhood-Adulthood Transition

Gastrointestinal disorders, although clinically heterogeneous, share pathogenic mechanisms, including genetic susceptibility, impaired gut barrier function, altered microbiota, and environmental triggers (infections, social and behavioral factors, epigenetic control, and diet). Gut microbiota has been studied for inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) in either children or adults, while modifiable gut microbiota features, acting as risk and premorbid factors along the childhood-adulthood transition, have not been thoroughly investigated so far. Indeed, the relationship between variations of the entire host/microbiota/environmental scenario and clinical phenotypes is still not fully understood. In this respect, tracking gut dysbiosis grading may help deciphering host phenotype-genotype associations and microbiota shifts in an integrated top-down omics-based approach within large-scale pediatric and adult case-control cohorts. Large-scale gut microbiota signatures and host inflammation patterns may be integrated with dietary habits, under genetic and epigenetic constraints, providing gut dysbiosis profiles acting as risk predictors of IBD or IBS in preclinical cases. Tracking dysbiosis supports new personalized/stratified IBD and IBS prevention programmes, generating Decision Support System tools. They include (1) high risk or flare-up recurrence -omics-based dysbiosis profiles; (2) microbial and molecular biomarkers of health and disease; (3) -omics-based pipelines for laboratory medicine diagnostics; (4) health apps for self-management of score-based dietary profiles, which can be shared with clinicians for nutritional habit and lifestyle amendment; (5) -omics profiling data warehousing and public repositories for IBD and IBS profile consultation. Dysbiosis-related indexes can represent novel laboratory and clinical medicine tools preventing or postponing the disease, finally interfering with its natural history.

How to Manipulate the Microbiota: Fecal Microbiota Transplantation

Fecal microbiota transplantation (FMT) is a rather straightforward therapy that manipulates the human gastrointestinal (GI) microbiota, by which a healthy donor microbiota is transferred into an existing but disturbed microbial ecosystem. This is a natural process that occurs already at birth; infants are rapidly colonized by a specific microbial community, the composition of which strongly depends on the mode of delivery and which therefore most likely originates from the mother (Palmer et al. 2007; Tannock et al. 1990). Since this early life microbial community already contains most, if not all, of the predominantly anaerobic microbes that are only found in the GI tract, it is reasonable to assume that early life colonization is the ultimate natural fecal transplantation.

Innate Immune Defenses Mediated by Two ILC Subsets Are Critical for Protection against Acute Clostridium difficile Infection

Infection with the opportunistic enteric pathogen Clostridium difficile is an increasingly common clinical complication that follows antibiotic treatment-induced gut microbiota perturbation. Innate lymphoid cells (ILCs) are early responders to enteric pathogens; however, their role during C. difficile infection is undefined. To identify immune pathways that mediate recovery from C. difficile infection, we challenged C57BL/6, Rag1(-/-) (which lack T and B cells), and Rag2(-/-)Il2rg(-/-) (Ragγc(-/-)) mice (which additionally lack ILCs) with C. difficile. In contrast to Rag1(-/-) mice, ILC-deficient Ragγc(-/-) mice rapidly succumbed to infection. Rag1(-/-) but not Ragγc(-/-) mice upregulate expression of ILC1- or ILC3-associated proteins following C. difficile infection. Protection against infection was restored by transferring ILCs into Ragγc(-/-) mice. While ILC3s made a minor contribution to resistance, loss of IFN-γ or T-bet-expressing ILC1s in Rag1(-/-) mice increased susceptibility to C. difficile. These data demonstrate a critical role for ILC1s in defense against C. difficile.