Low Cure Rates in Controlled Trials of Fecal Microbiota Transplantation for Recurrent Clostridium difficile Infection: A Systematic Review and Meta-analysis

Clostridioides difficile infection study models and prospectives for probing the microbe-host interface

Clostridioides difficile infection (CDI) is an urgent public health threat with a high rate of recurrence and limited treatment options. In vivo models have been indispensable in understanding CDI pathophysiology and establishing treatment protocols and continue to be essential in pre-clinal testing. More importantly, in vivo models offer the opportunity to probe the complex systemic host response to the microbe, which is impossible to recapitulate in vitro. Nonetheless, constraints related to the availability of animal models, cost, ethical considerations, and regulatory control limit their accessibility for basic research. Furthermore, physiological and habitual divergences between animal models and humans often result in poor translatability to human patients. In addition to being more accessible, in vitro CDI models offer more control over experimental parameters and allow dynamic analysis of early infection. In vitro fermentation offers models for probing microbe-microbe and microbe-microbiome interactions, while continuous multi-stage platforms allow opportunities to study C. difficile pathophysiology and treatment in context with human-derived microbiota. However, these platforms are not suitable for probing the host-pathogen interface, leaving the challenge of modeling early CDI unanswered. As a result, alternative in vitro co-culture platforms are being developed. This review evaluates the strengths and weaknesses of each approach, as well as future directions for C. difficile research.

A Randomized Controlled Trial of Efficacy and Safety of Fecal Microbiota Transplant for Preventing Recurrent Clostridioides difficile Infection

BACKGROUND

Clostridioides difficile infection (CDI) is the most common cause of healthcare-associated infections in US hospitals, with 15%-30% of patients experiencing recurrence. The aim of our randomized, double-blind clinical trial was to assess the efficacy of capsule-delivered fecal microbiota transplant (FMT) versus placebo in reducing recurrent diarrhea and CDI recurrence. The secondary aim was FMT safety assessment.

METHODS

Between 2018 and 2022, Veterans across the Veterans Health Administration system with recurrent CDI who responded to antibiotic treatment were randomized in a 1:1 ratio to oral FMT or placebo capsules. Randomization was stratified by number of prior CDI recurrences (1 or ≥2). The primary endpoint was clinical recurrence by day 56, defined as >3 unformed stools daily for ≥2 days with or without laboratory confirmation of C. difficile, or death within 56 days.

RESULTS

The study was stopped due to futility after meeting prespecified criteria. Of 153 participants (76 FMT, 77 placebo) with an average age of 66.5 years, 25 participants (32.9%) in the FMT arm and 23 (29.9%) in the placebo arm experienced the primary endpoint of diarrhea and possible or definite CDI recurrence or death within 56 days of capsule administration (absolute difference, 3.0% [95% confidence interval, -11.7% to 17.7%]). Stratification by number of recurrences revealed no statistically significant differences. There were no clinically important differences in adverse events.

CONCLUSIONS

FMT therapy versus placebo did not reduce CDI recurrence or death at 56 days. There were no meaningful differences in adverse events between treatment groups.

CLINICAL TRIALS REGISTRATION

NCT03005379.

Safety and Tolerability of CP101, a Full-Spectrum, Oral Microbiome Therapeutic for the Prevention of Recurrent Clostridioides difficile Infection: A Phase 2 Randomized Controlled Trial

BACKGROUND & AIMS

Recurrent Clostridioides difficile infections (CDIs) remain common. While novel microbiome therapeutics gain approval, the efficacy of a full-spectrum, oral microbiome therapeutic is unknown. This study aimed to determine the safety and efficacy of CP101, an orally administered microbiome therapeutic, to restore a diverse microbiome and prevent recurrent CDI in a broad population.

METHODS

We conducted a multicenter, phase 2, double-blind, randomized, placebo-controlled trial in adults with recurrent CDI. Participants with one or more CDI recurrences and diagnosis by polymerase chain reaction or toxin enzyme immunoassay for the qualifying episode were included. Participants were randomized 1:1 to receive a single oral dose of either CP101 (∼6 × 1011 colony-forming units of lyophilized microbial cells) or placebo after standard-of-care antibiotics. The primary efficacy endpoint was the proportion of participants without CDI recurrence through week 8. Safety, efficacy, and microbiome endpoints were evaluated through weeks 8 and 24.

RESULTS

A total of 198 participants were analyzed: CP101 (n = 102) and placebo (n = 96). Overall, 27.5% had a first recurrence, and 62.7% were diagnosed by polymerase chain reaction-based testing. The proportion without CDI recurrence through week 8 was significantly higher in the CP101 group compared to the placebo group (74.5% [76 of 102] vs 61.5% [59 of 96], respectively; P = .0488), with durable efficacy observed through week 24 (73.5% [75 of 102] vs 59.4% [57 of 96], respectively; P = .0347). Similar efficacy was observed regardless of diagnostic modality or number of CDI recurrences. Rapid and durable increase in microbiome diversity was observed in the CP101 group compared to the placebo group. The incidence of adverse events was similar between the 2 groups.

CONCLUSIONS

CP101 was superior to placebo in reducing recurrent CDI with a safety profile similar to placebo. (ClinicalTrials.gov, Number NCT03110133).

The presence of Clostridioides difficile in faeces before and after faecal microbiota transplantation and its relation with recurrent C. difficile infection and the gut microbiota in a Dutch cohort

OBJECTIVES

The objectives of this study are to investigate the presence of Clostridioides difficile in faeces of patients with recurrent C. difficile infection (rCDI) before and after faecal microbiota transplantation (FMT) and to identify risk factors for faecal C. difficile and C. difficile infection (CDI) recurrence.

METHODS

n = 83 faecal sample triads (pre-FMT [∼1 day], post-FMT [∼3 weeks], and a corresponding FMT donor sample), and n = 22 long-term (∼1-3 years) follow-up faecal samples were collected from FMT-treated patients. The presence of C. difficile in faeces was assessed by enrichment broth culture and PCR (tcdB gene) and associated with patient characteristics, FMT outcome, duration of pre-FMT vancomycin, FMT donor, post-FMT antibiotic use, and faecal microbiota composition (shotgun metagenomics).

RESULTS

The FMT cure rate for rCDI was 92.8% (77/83), with six early CDI recurrences (<2 months post-FMT). Toxigenic C. difficile was cultured in 27.7% (23/83) of all patients post-FMT, 23.4% (18/77) of patients cured 2 months post-FMT, and 13.6% (3/22) at long-term follow-up. Early CDI recurrence (n = 6) was associated with positive C. difficile culture post-FMT (21.7% [5/23] vs. 1.7% [1/60], p 0.01), post-FMT antibiotics (30.0% [3/10] vs. 4.6% [3/65], p 0.03), and a short course of pre-FMT vancomycin (median 6.0 days, IQR [5-12] vs. 18 days, IQR [10.8-29], p < 0.05). Additionally, positive C. difficile culture directly pre-FMT was associated with a short course of pre-FMT vancomycin (median 9 days IQR [5-18] vs. 17 days, IQR [10-29.2], p 0.04). Gut microbiota analyses did not reveal signatures associated with C. difficile culture result, despite statistically non-significant trends in relative abundances of the Enterobacteriaceae family, and Dorea, Roseburia, and Clostridiales species.

DISCUSSION

Although eradication of C. difficile is not required for clinical cure of rCDI by FMT, it is associated with reduced prevalence of early CDI recurrence, as are the full completion of pre-FMT vancomycin (at least 10 days) and avoiding post-FMT antibiotics.

Microbiota restoration for recurrent Clostridioides difficile infection

Since the publication of the recent North American and European guidelines on management of Clostridioides difficile infection (CDI), new evidence describing the epidemiology, testing and treatment of CDI has emerged. Despite all advances in infection control and antibiotic stewardship, the incidence and burden of CDI in the hospitals and the community remains at a stable high. Coupled with the incidence of primary CDI, there is a stable high incidence of recurrent CDI. Testing for primary and recurrent CDI remains a clinical challenge owing to high sensitivity of the PCR (leading to false positives) and somewhat limited sensitivity of EIA for toxin. The pathophysiology of recurrent CDI involves an ongoing disruption of the microbiota owing to the infection and the treatment of CDI employed. Broad spectrum antibiotics such as vancomycin leads to further disruption of microbiota compared to fidaxomicin which has a lower disruption of the microbiota and leads to fewer recurrences. Owing to these data fidaxomicin is considered as the first line antibiotic for recurrent CDI. Intravenous bezlotoxumab is a monoclonal antibody that reduces the risk of recurrence in high-risk patients but does not restore the microbiota. Experimental fecal microbiota transplantation (FMT) has been available for more than a decade. Owing to the success of FMT, two new non-invasive donor dependent Food and Drug Administration (FDA) approved therapies have been available since late 2022. This review summarizes all these conundrums regarding CDI and provides clinical pearls to use in day-to-day practice.

Comparative effectiveness of treatments for recurrent Clostridioides difficile infection: a network meta-analysis of randomized controlled trials

Background

Clostridioides difficile infection (CDI) is the most common cause of healthcare-associated infectious diarrhea. A major clinical challenge is recurrent CDI (rCDI) without effective standard drug-based therapy. Additionally, a comprehensive comparison of various therapy effectiveness in rCDI patients is still under investigation.

Methods

A Bayesian network meta-analysis (NMA) of randomized control trials up to March 2024 was performed to investigate the efficacy of rCDI interventions.

Results

Seventeen trials were included, comprising 4,148 CDI patients with ten interventions, including fecal microbiota transplantation (FMT) by lower gastrointestinal (LGI), FMT by upper gastrointestinal (UGI), Autologous FMT (AFMT), vancomycin + FMT, vancomycin, placebo, fidaxomicin, Vowst (SER109), Rebyota (RBX2660), and monoclonal antibody. NMA showed that FMT by LGI had the highest efficacy in treating rCDIs with an odds ratio (95% confidence interval) of 32.33 (4.03, 248.69) compared with placebo. FMT by UGI also showed high efficacy, whereas the efficacy comparison between FMT by LGI and UGI was not statistically significant (ORs) (95% CI), 1.72 (0.65, 5.21). The rankogram and surface under the cumulative ranking curve (SUCRA) also showed FMT by LGI ranked at the top and FMT by UGI ranked second in the curative effect.

Conclusion

NMA demonstrates FMT's significant efficacy in rCDI management, regardless of administration route (lower or upper gastrointestinal). Despite its significant benefits, FMT's safety is a concern due to the lack of standardized FDAcompliant manufacturing and oversight. Microbiota-based therapies also exhibit potential. However, limited research mandates further clinical exploration. Antibiotics, in contrast, display comparatively reduced efficacy in rCDI, potentially linked to disruptions in native gut microflora balance.

Systematic Review

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=368435, Identifier CRD42022368435.

Fecal Microbiota, Live-jslm for the Prevention of Recurrent Clostridioides difficile Infection : Subgroup Analysis of PUNCH CD2 and PUNCH CD3

GOALS

To assess fecal microbiota, live-jslm (REBYOTA, abbreviated as RBL, formerly RBX2660) efficacy and safety in participants grouped by recurrent Clostridioides difficile infection (rCDI) risk factors and treatment-related variables.

BACKGROUND

RBL is the first microbiota-based live biotherapeutic approved by the US Food and Drug Administration for the prevention of rCDI in adults after antibiotic treatment for rCDI.

STUDY

Treatment success rates across subgroups for PUNCH CD3 (NCT03244644) were estimated using a Bayesian hierarchical model, borrowing data from PUNCH CD2 (NCT02299570). Treatment-emergent adverse events were summarized for the double-blind treatment period within 8 weeks.

RESULTS

Treatment differences between RBL and placebo at 8 weeks were similar to the total population for most subgroups. Treatment effect sizes were similar between CDI tests, higher for oral vancomycin courses >14 days versus ≤14 days and higher for antibiotic washout periods of 3 days versus ≤2 days. The largest reductions in the rate of rCDI with RBL versus placebo were observed for participants with a 3-day CDI antibiotic washout period and participants with ≥4 previous CDI episodes. Most RBL-treated participants experienced TEAEs that were mild or moderate in severity and related to preexisting conditions.

CONCLUSION

This analysis provides further evidence of RBL efficacy and safety across subgroups, including those at high risk for rCDI.

Validation of Lyophilized Human Fecal Microbiota for the Treatment of Clostridioides difficile Infection: A Pilot Study with Pharmacoeconomic Analysis of a Middle-Income Country-Promicrobioma Project

BACKGROUND

Clostridioides difficile infection (CDI) represents a prevalent and potentially severe health concern linked to the usage of broad-spectrum antibiotics. The aim of this study was to evaluate a new lyophilized product based on human fecal microbiota for transplant, including cost-benefit analysis in the treatment of recurrent or refractory CDI.

METHODS

The product for fecal microbiota transplant was obtained from two donors. Microbiological, viability, and genomic analysis were evaluated. After validation, a clinical pilot study including recurrent or refractory CDI with 24 patients was performed. Clinical response and 4-week recurrence were the outcome. Cost-benefit analysis compared the fecal microbiota transplant with conventional retreatment with vancomycin or metronidazole.

RESULTS

The microbiota for transplant presented significant bacterial viability, with and adequate balance of Firmicutes and Bacteroidetes. The clinical response with the microbiota transplant was 92%. In financial terms, estimated expenditure for CDI solely related to recurrence, based on stochastic modeling, totals USD 222.8 million per year in Brazil.

CONCLUSIONS

The lyophilized human fecal microbiota for transplant is safe and can be an important step for a new product with low cost, even with genomic sequencing. Fecal microbiota transplantation emerges as a more cost-effective alternative compared to antimicrobials in the retreatment of CDI.

Significant Publications on Infectious Diseases Pharmacotherapy in 2022

Purpose: To provide summarization of the most significant infectious diseases (ID) pharmacotherapy articles published in peer-reviewed literature in 2022. Summary: Members of the Houston Infectious Diseases Network (HIDN) nominated notable articles providing significant contributions to ID pharmacotherapy in 2022. Article nominations included those pertaining to general ID, as well as those including coronavirus disease 2019 (COVID-19), and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) pharmacotherapy. A total of 71 articles were nominated by HIDN. Members: 68 articles pertaining to general ID pharmacotherapy and 3 articles focusing on HIV/AIDS. To aid selection of the most these most notable articles of 2022, a survey was created and distributed to members of the Society of Infectious Diseases Pharmacists (SIDP). Of the 153 SIDP members who participated in the survey, there were 128 recorded votes for the top 10 general ID pharmacotherapy articles and 30 votes recorded for the top HIV/AIDS article. The most notable publications are summarized. Conclusion: Post pandemic significant advances in antimicrobial stewardship and infectious disease states continues to occur in a world recently focused on the coronavirus disease 2019 (COVID-19) global pandemic. Continuous growth in publication of ID-related articles over the past year lends towards the aims of this review to aid clinicians in remaining current on key practice-changing ID pharmacotherapy publications from 2022.

Fecal microbiota live - jslm (Rebyota™/RBL) for management of recurrent Clostridioides difficile infection

There is an unmet need for effective treatments of Clostridioides difficile infection, an emerging health crisis in the United States. The management of C. difficile infection should include treatment of active infection and a strategy to prevent recurrence. Current gold standard therapy includes oral antibiotics which predispose patients to gut dysbiosis and increase the risk of recurrent infection. Addressing dysbiosis via fecal microbiota transplantation is an active and promising area of research, but studies have lacked standardization which makes outcome and safety data difficult to interpret. Rebyota™, formerly known as RBX2660, is a live biotherapeutic product designed using a standardized protocol and manufacturing process that has been shown to be effective for preventing recurrent C. difficile infection.

The Progression of Microbiome Therapeutics for the Management of Gastrointestinal Diseases and Beyond

There has been an increased ability to investigate the human microbiota through next-generation sequencing and functional assessment. This advancement has rapidly expanded our ability to study and manipulate the gastrointestinal microbiome to mitigate disease. Fecal microbiota transplantation, a therapy that broadly transfers the entire intestinal ecosystem, has been explored as a potential therapeutic in a variety of gastrointestinal, hepatic, and extraintestinal conditions. The field, however, continues to evolve, with a movement toward precision microbiome therapeutics, individualizing care for various disorders. This review will describe the use of fecal microbiota transplantation, microbiota restoration, and precision microbiome therapeutics, focusing on gastrointestinal and hepatic diseases.

Standards for fecal microbiota transplant: Tools and therapeutic advances

Fecal microbiota transplantation (FMT) has been demonstrated to be efficacious in preventing recurrent Clostridioides difficile (C. difficile) infections, and is being investigated for treatment of several other diseases including inflammatory bowel disease, cancer, obesity, liver disease, and diabetes. To speed up the translation of FMT into clinical practice as a safe and standardized therapeutic intervention, additional evidence-based technical and regulatory guidance is needed. To this end in May of 2022, the International Alliance for Biological Standardization (IABS) and the BIOASTER Microbiology Technology Institute hosted a second webinar to discuss key issues still impeding the advancement and standardization of FMT. The goal of this two-day webinar was to provide a forum for scientific experts to share and discuss data and key challenges with one another. Discussion included a focus on the evaluation of safety, efficacy, clinical trial design, reproducibility and accuracy in obtained microbiome measurements and data reporting, and the potential for standardization across these areas. It also focused on increasing the application potential and visibility of FMT beyond treating C. difficile infections.

[Fecal Microbiota Transfer (FMT) in Germany - Status and Perspective]

INTRODUCTION

Fecal microbiota transfer (FMT) is a treatment to modulate the gastrointestinal microbiota. Its use in recurrent Clostridioides difficile infection (rCDI) is established throughout Europe and recommended in national and international guidelines. In Germany, the FMT is codeable in the hospital reimbursement system. A comprehensive survey on the frequency of use based on this coding is missing so far.

MATERIAL AND METHODOLOGY

Reports of the Institute for Hospital Remuneration (InEK), the Federal Statistical Office (DESTATIS), and hospital quality reports 2015-2021 were examined for FMT coding and evaluated in a structured expert consultation.

RESULTS

Between 2015 and 2021, 1,645 FMT procedures were coded by 175 hospitals. From 2016 to 2018, this was a median of 293 (274-313) FMT annually, followed by a steady decline in subsequent years to 119 FMT in 2021. Patients with FMT were 57.7% female, median age 74 years, and FMT was applied colonoscopically in 72.2%. CDI was the primary diagnosis in 86.8% of cases, followed by ulcerative colitis in 7.6%.

DISCUSSION

In Germany, FMT is used less frequently than in the European comparison. One application hurdle is the regulatory classification of FMT as a non-approved drug, which leads to significantly higher costs in manufacturing and administration and makes reimbursement difficult. The European Commission recently proposed a regulation to classify FMT as a transplant. This could prospectively change the regulatory situation of FMT in Germany and thus contribute to a nationwide offer of a therapeutic procedure recommended in guidelines.

Microbiota-Based Live Biotherapeutic Products for Clostridioides Difficile Infection- The Devil is in the Details

Clostridioides difficile infection (CDI) remains a significant contributor to healthcare costs and morbidity due to high rates of recurrence. Currently, available antibiotic treatment strategies further disrupt the fecal microbiome and do not address the alterations in commensal flora (dysbiosis) that set the stage for CDI. Advances in microbiome-based research have resulted in the development of new agents, classified as live biotherapeutic products (LBPs), for preventing recurrent CDI (rCDI) by restoring eubiosis. Prior to the LBPs, fecal microbiota transplantation (FMT) was available for this purpose; however, lack of large-scale availability and safety concerns have remained barriers to its widespread use. The LBPs are an exciting development, but questions remain. Some are derived directly from human stool while other developmental products contain a defined microbial consortium manufactured ex vivo, and they may be composed of either living bacteria or their spores, making it difficult to compare members of this heterogenous drug class to one another. None have been studied head-to head or against FMT in preventing rCDI. As a class, they have considerable variability in their biologic composition, biopharmaceutic science, route of administration, stages of development, and clinical trial data. This review will start by explaining the role of dysbiosis in CDI, then give the details of the biopharmaceutical components for the LBPs which are approved or in development including how they differ from FMT and from one another. We then discuss the clinical trials of the LBPs currently approved for rCDI and end with the future clinical directions of LBPs beyond C. difficile.

Clostridioides difficile infections; new treatments and future perspectives

PURPOSE OF REVIEW

As a significant cause of global morbidity and mortality, Clostridioides difficile infections (CDIs) are listed by the Centres for Disease Control and prevention as one of the top 5 urgent threats in the USA. CDI occurs from gut microbiome dysbiosis, typically through antibiotic-mediated disruption; however, antibiotics are the treatment of choice, which can result in recurrent infections. Here, we highlight new treatments available and provide a perspective on different classes of future treatments.

RECENT FINDINGS

Due to the reduced risk of disease recurrence, the microbiome-sparing antibiotic Fidaxomicin has been recommended as the first-line treatment for C. difficile infection. Based on the success of faecal microbiota transplantations (FMT) in treating CDI recurrence, defined microbiome biotherapeutics offer a safer and more tightly controlled alterative as an adjunct to antibiotic therapy. Given the association between antibiotic-mediated dysbiosis of the intestinal microbiota and the recurrence of CDI, future prospective therapies aim to reduce the dependence on antibiotics for the treatment of CDI.

SUMMARY

With current first-in-line antibiotic therapy options associated with high levels of recurrent CDI, the availability of new generation targeted therapeutics can really impact treatment success. There are still unknowns about the long-term implications of these new CDI therapeutics, but efforts to expand the CDI treatment toolbox can offer multiple solutions for clinicians to treat this multifaceted infectious disease to reduce patient suffering.

Review Article: Safety of Live Biotherapeutic Products Used for the Prevention of Clostridioides difficile Infection Recurrence

Live biotherapeutic products (LBPs) represent a new class of therapeutics indicated to prevent the recurrence of Clostridioides difficile infection (CDI) in adults. However, microbiota-based therapies have been used in CDI management before the Food and Drug Administration (FDA) designated this new drug class. The regulation of these microbiome-based therapies has varied, and several safety concerns have arisen over time. Requirements established by the FDA regarding the development of LBPs minimizes many of these prior concerns, and phase III trials have proven the safety and efficacy of 2 stool donor-derived LBPs: fecal microbiota, live-jslm (Rebyota™; formerly RBX2660) and fecal microbiota spores, live-brpk (Vowst™; formerly SER-109). Mild gastrointestinal side effects are common, but no severe drug-related adverse events have been reported with their use to date. A third LBP entering phase III clinical trials, VE303, follows a novel approach by sourcing bacterial strains from clonal cell banks and has demonstrated a similarly favorable safety profile.

Manufacturing Processes of a Purified Microbiome Therapeutic Reduce Risk of Transmission of Potential Bacterial Pathogens in Donor Stool

BACKGROUND

Although fecal microbiota transplant has been used to prevent recurrent Clostridioides difficile infection (rCDI), documented pathogen transmissions highlight inherent safety risks of minimally processed stool. We describe manufacturing processes for fecal microbiota spores, live (VOWST; VOS, formerly SER-109), a microbiota-based oral therapeutic of Firmicutes spores.

METHODS

Bacterial inactivation kill curves were obtained after ethanol exposure for 4 model organisms spiked into process intermediates.

RESULTS

Bacterial log reduction factors ranged from 6.5 log10 to 7.4 log10 and lysis of spiked organisms occurred rapidly within 30 seconds.

CONCLUSIONS

These experiments demonstrate substantial and rapid inactivation of representative organisms, supporting the potential benefit of VOS manufacturing processes to mitigate risk.

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.

Fecal microbiota transplantation for recurrent Clostridioides difficile infection in frail and very old patients

BACKGROUND

Older age is a well-known risk factor for recurrent and severe Clostridioides difficile infection (CDI). Fecal microbiota transplantation (FMT) is widely recognized as an effective and safe therapeutic option for the treatment of recurrent CDI (rCDI). However, the efficacy and safety of FMT for rCDI in very old patients are uncertain. This study evaluated the efficacy and safety of FMT in a group of very old subjects with rCDI, and the reliability of overall comorbidity and frailty assessment for identifying patients at higher risk of worse clinical outcomes.

METHODS

This is a retrospective single-center study including patients ≥85 years undergoing FMT for rCDI between 2014 and 2022. Primary outcomes included efficacy of FMT, defined as cure of CDI at 8 week-follow-up, and safety evaluation. At baseline, comorbidity was measured with the Charlson Comorbidity Index (CCI). Frailty was measured with the Clinical Frailty Scale (CFS).

RESULTS

Overall, 43 patients with a median age of 88 years underwent FMT by colonoscopy in the study period. The rate of first FMT success was 77%. Five of the 10 patients who failed the first FMT infusion were cured after repeat FMT, with an overall efficacy of 88%. In patients with successful treatment, the CFS was significantly lower compared to those who failed the FMT or underwent repeat FMT (p < 0.01 for both). Mild adverse events occurred in 11 patients (25%). One death, not related to FMT or rCDI, occurred within 7 days from the first procedure.

CONCLUSIONS

FMT is effective and safe in very old patients. Frailty and high comorbidity do not limit use of FMT in these patients. Frailty assessment has potential to better identify patients at higher risk of worse outcomes or for repeat treatment with FMT.

A cost-utility analysis of two Clostridioides difficile infection guideline treatment pathways

OBJECTIVES

Treatment guidelines are key drivers of prescribing practice in the management of Clostridioides difficile infection (CDI), but recommendations on best practice can vary. We conducted a cost-utility analysis to compare the treatment pathway recommended by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guideline with the pathway proposed by the National Institute for Health and Care Excellence (NICE) guideline, from the perspective of the UK National Health Service.

METHODS

A decision tree modelling approach was adopted to reflect the treatment pathway for CDI as outlined in ESCMID and NICE guidelines. Patients experiencing a CDI infection received up to three treatments per infection to achieve a response and could subsequently experience up to two recurrences. Data on patient demographics, treatment response, recurrence, utilities, CDI-related mortality, and costs were taken from published literature.

RESULTS

The ESCMID treatment pathway was cost-effective versus the NICE treatment pathway at a threshold of £20 000 per quality-adjusted life year gained, with an incremental cost-effectiveness ratio of £4931. Cost-effectiveness was driven by differences in index infection recommendations (ESCMID recommends fidaxomicin as first-line treatment whereas NICE recommends vancomycin). The model results were robust to variations in inputs investigated in scenarios and sensitivity analyses, and probabilistic sensitivity analysis demonstrated that the ESCMID guideline treatment strategy had a 100% likelihood of being cost-effective versus the NICE treatment strategy.

DISCUSSION

Compared with the NICE guideline, the ESCMID guideline recommendations for treating an index CDI represent the most cost-effective use of healthcare resources from the perspective of the UK National Health Service.

Is there a role for microbiome-based approach in common variable immunodeficiency?

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by low levels of serum immunoglobulins and increased susceptibility to infections, autoimmune disorders and cancer. CVID embraces a plethora of heterogeneous manifestations linked to complex immune dysregulation. While CVID is thought to be due to genetic defects, the exact cause of this immune disorder is unknown in the large majority of cases. Compelling evidences support a linkage between the gut microbiome and the CVID pathogenesis, therefore a potential for microbiome-based treatments to be a therapeutic pathway for this disorder. Here we discuss the potential of treating CVID patients by developing a gut microbiome-based personalized approach, including diet, prebiotics, probiotics, postbiotics and fecal microbiota transplantation. We also highlight the need for a better understanding of microbiota-host interactions in CVID patients to prime the development of improved preventive strategies and specific therapeutic targets.

p-Cresol Sulfate Is a Sensitive Urinary Marker of Fecal Microbiota Transplantation and Antibiotics Treatments in Human Patients and Mouse Models

Fecal microbiota transplantation (FMT) has emerged as a highly effective therapy for recurrent Clostridioides difficile infection (rCDI) and also a potential therapy for other diseases associated with dysbiotic gut microbiota. Monitoring metabolic changes in biofluids and excreta is a noninvasive approach to identify the biomarkers of microbial recolonization and to understand the metabolic influences of FMT on the host. In this study, the pre-FMT and post FMT urine samples from 11 rCDI patients were compared through metabolomic analyses for FMT-induced metabolic changes. The results showed that p-cresol sulfate in urine, a microbial metabolite of tyrosine, was rapidly elevated by FMT and much more responsive than other microbial metabolites of aromatic amino acids (AAAs). Because patients were treated with vancomycin prior to FMT, the influence of vancomycin on the microbial metabolism of AAAs was examined in a mouse feeding trial, in which the decreases in p-cresol sulfate, phenylacetylglycine, and indoxyl sulfate in urine were accompanied with significant increases in their AAA precursors in feces. The inhibitory effects of antibiotics and the recovering effects of FMT on the microbial metabolism of AAAs were further validated in a mouse model of FMT. Overall, urinary p-cresol sulfate may function as a sensitive and convenient therapeutic indicator on the effectiveness of antibiotics and FMT for the desired manipulation of gut microbiota in human patients.

Cost-Effectiveness Analysis of Antimicrobial Prescribing in the Treatment of Clostridioides Difficile Infection in England

BACKGROUND

An economic model was developed with guidance from the National Institute for Health and Care Excellence (NICE) 'Managing Common Infections' (MCI) Committee to evaluate the cost effectiveness of different antibiotic treatment sequences for treating Clostridioides difficile infection (CDI) in England.

METHODS

The model consisted of a 90-day decision tree followed by a lifetime cohort Markov model. Efficacy data were taken from a network meta-analysis and published literature, while cost, utility and mortality data were taken from published literature. A treatment sequence was defined as a first-line intervention or a different second-line intervention, and used constant third- and fourth-line interventions. The possible first- and second-line interventions were vancomycin, metronidazole, teicoplanin and fidaxomicin (standard and extended regimens). Total costs and quality-adjusted life-years (QALYs) were calculated and were used to run a fully incremental cost-effectiveness analysis. Threshold analysis was conducted around pricing.

RESULTS

Sequences including teicoplanin, fidaxomicin (extended regimen) and second-line metronidazole were excluded based on recommendations from the committee. The final pairwise comparison was between first-line vancomycin and second-line fidaxomicin (VAN-FID), and the reverse (FID-VAN). The incremental cost-effectiveness ratio for FID-VAN compared with VAN-FID was £156,000 per QALY gained, and FID-VAN had a 0.2% likelihood of being cost effective at a £20,000 threshold.

CONCLUSION

First-line vancomycin and second-line fidaxomicin was the most cost-effective treatment sequence at the NICE threshold for treating CDI in England. The main limitation of this study was that the initial cure and recurrence rates of each intervention were applied constantly across each line of treatment and each round of recurrence.

Biofilm Formation of Clostridioides difficile, Toxin Production and Alternatives to Conventional Antibiotics in the Treatment of CDI

Clostridioides difficile is considered a nosocomial pathogen that flares up in patients exposed to antibiotic treatment. However, four out of ten patients diagnosed with C. difficile infection (CDI) acquired the infection from non-hospitalized individuals, many of whom have not been treated with antibiotics. Treatment of recurrent CDI (rCDI) with antibiotics, especially vancomycin (VAN) and metronidazole (MNZ), increases the risk of experiencing a relapse by as much as 70%. Fidaxomicin, on the other hand, proved more effective than VAN and MNZ by preventing the initial transcription of RNA toxin genes. Alternative forms of treatment include quorum quenching (QQ) that blocks toxin synthesis, binding of small anion molecules such as tolevamer to toxins, monoclonal antibodies, such as bezlotoxumab and actoxumab, bacteriophage therapy, probiotics, and fecal microbial transplants (FMTs). This review summarizes factors that affect the colonization of C. difficile and the pathogenicity of toxins TcdA and TcdB. The different approaches experimented with in the destruction of C. difficile and treatment of CDI are evaluated.

Safety of fecal microbiota, live-jslm (REBYOTA™) in individuals with recurrent Clostridioides difficile infection: data from five prospective clinical trials

Background

Microbiota-based treatments reduce the incidence of recurrent Clostridioides difficile infections (rCDIs), but prospectively collected safety data needed to broaden patient access and protect public health have been limited.

Objectives

We provide cumulative safety data from five prospective clinical trials evaluating fecal microbiota, live-jslm (RBL) - the first microbiota-based live biotherapeutic product approved by the US Food and Drug Administration - for preventing rCDI in adults.

Design

Integrated safety analysis includes three phase II trials (PUNCH CD, PUNCH CD2, PUNCH Open-Label) and two phase III trials (PUNCH CD3, PUNCH CD3-OLS) of RBL.

Methods

Trial participants were at least 18 years of age with documented rCDI who completed standard-of-care antibiotic therapy before treatment with RBL. Assigned study treatment regimen was one or two doses of RBL (or placebo) administered rectally, depending on the trial design. In four of the five trials, participants with CDI recurrence within 8 weeks after RBL or placebo administration were eligible for treatment with open-label RBL. Treatment-emergent adverse events (TEAEs) were recorded for at least 6 months following last study treatment; in PUNCH CD2 and PUNCH Open-Label trials, TEAEs and serious TEAEs were collected through 12 and 24 months, respectively.

Results

Among the five trials, 978 participants received at least one dose of RBL (assigned treatment or after recurrence) and 83 participants received placebo only. TEAEs were reported in 60.2% of Placebo Only participants and 66.4% of RBL Only participants. Only abdominal pain, nausea, and flatulence were significantly higher in the RBL Only group compared with the Placebo Only group. Most TEAEs were mild or moderate in severity and were most frequently related to preexisting conditions. There were no reported infections for which the causative pathogen was traced to RBL. Potentially life-threatening TEAEs were infrequent (3.0% of participants).

Conclusion

Across five clinical trials, RBL was well tolerated in adults with rCDI. In aggregate, these data consistently demonstrated the safety of RBL.

Microbiome-Related and Infection Control Approaches to Primary and Secondary Prevention of Clostridioides difficile Infections

Clostridioides difficile infections (CDIs) have decreased in the past years, but since 2021, some hospitals have reported an increase in CDI rates. CDI remains a global concern and has been identified as an urgent threat to healthcare. Although multiple treatment options are available, prevention strategies are more limited. As CDI is an opportunistic infection that arises after the normally protective microbiome has been disrupted, preventive measures aimed at restoring the microbiome have been tested. Our aim is to update the present knowledge on these various preventive strategies published in the past five years (2018-2023) to guide clinicians and healthcare systems on how to best prevent CDI. A literature search was conducted using databases (PubMed, Google Scholar, and clinicaltrials.gov) for phase 2-3 clinical trials for the primary or secondary prevention of CDI and microbiome and probiotics. As the main factor for Clostridium difficile infections is the disruption of the normally protective intestinal microbiome, strategies aimed at restoring the microbiome seem most rational. Some strains of probiotics, the use of fecal microbial therapy, and live biotherapeutic products offer promise to fill this niche; although, more large randomized controlled trials are needed that document the shifts in the microbiome population.

Interconnection between Microbiota-Gut-Brain Axis and Autism Spectrum Disorder Comparing Therapeutic Options: A Scoping Review

BACKGROUND

Autism spectrum disorder (ASD) is a group of neurodevelopmental illnesses characterized by difficulty in social communication, social interaction, and repetitive behaviors. These clinical diagnostic criteria can be seen in children as early as one year old and are commonly associated with long-term difficulties. ASD is connected with a higher frequency of various medical diseases such as gastrointestinal complaints, seizures, anxiety, interrupted sleep, and immunological dysfunction, in addition to the range of developmental abnormalities listed.

METHODS

From 1 January 2013 to 28 February 2023, we searched PubMed, Scopus and Web of Science for English-language papers that matched our topic. The following Boolean keywords were utilized in the search approach: "autism" AND "microbiota". After deleting duplicates, a total of 2370 publications were found from the databases, yielding 1222 articles. (1148). Nine hundred and eighty-eight items were excluded after their titles and abstracts were scrutinized. The method resulted in the removal of 174 items for being off-topic. The final 18 articles for qualitative analysis are included in the evaluation.

CONCLUSION

The findings of this extensive study revealed that probiotics, prebiotics, their combination as synbiotics, fecal microbiota transplantation, and microbiota transfer therapy may benefit ASD patients suffering from both gastrointestinal and central nervous system symptoms.

Resolution rates in clinical trials for microbiota restoration for recurrent Clostridioides difficile infection: an updated systematic review and meta-analysis

Background

Microbiota restoration is highly effective to treat recurrent Clostridioides difficile infection (CDI) in observational studies (cure rates >90%) but efficacy in controlled clinical trials appears to be lower.

Objectives

To perform an updated meta-analysis to assess the efficacy of microbiota restoration for recurrent CDI in open-label registered prospective clinical trials compared to randomized controlled trials (RCTs).

Design

A systematic review and meta-analysis was conducted.

Data Sources and Methods

A systematic search of various databases was performed up to July 2022 to identify studies of interest. Clinical trials of microbiota restoration for recurrent CDI with clinical resolution with one dose were included. We calculated weighted pooled rates (WPRs) with 95% confidence intervals (CIs).

Results

In all, 19 clinical trials with 1176 recurrent CDI patients were included. Of the patients treated with microbiota restoration, 897 experienced a clinical cure with a single microbiota restoration therapy (WPR, 78%; 95% CI, 71-85%). There was significant heterogeneity among studies with an I2 of 88%. Analysis of trials with a control arm (non-microbiota restoration) revealed CDI resolution in 373 of 523 patients (WPR, 72%; 95% CI, 60-82%) with microbiota restoration. Among the nine open-label clinical trials, CDI resolution was seen in 524 of 653 patients after initial microbiota restoration (WPR, 84%; 95% CI, 74-92%). Comparison of resolution rates between RCTs and open-label trials revealed a lower cure rate in RCTs compared to open-label trials (WPR, 73 versus 84%, p < 0.0001).

Conclusions

Microbiota restoration in a randomized controlled setting leads to lower resolution rates compared to open label and observational settings, likely due to stricter definitions and inclusion criteria. Resolution rates in open-label studies were similar to observational studies.

Clostridioides difficile infection: microbe-microbe interactions and live biotherapeutics

Clostridioides difficile is a gram-positive, spore-forming, obligate anaerobe that infects the colon. C. difficile is estimated to cause nearly half a million cases in the United States annually, with about 29,000 associated deaths. Unfortunately, the current antibiotic treatment is not ideal. While antibiotics can treat the infections, they also disrupt the gut microbiota that mediates colonization resistance against enteric pathogens, including C. difficile; disrupted gut microbiota provides a window of opportunity for recurrent infections. Therefore, therapeutics that restore the gut microbiota and suppress C. difficile are being evaluated for safety and efficacy. This review will start with mechanisms by which gut bacteria affect C. difficile pathogenesis, followed by a discussion on biotherapeutics for recurrent C. difficile infections.

Retrospective Analysis of the Safety and Efficacy of Fecal Microbiota, Live-jslm (REBYOTATM) Administered Under Enforcement Discretion to Patients With Clostridioides difficile Infection

Background

Fecal microbiota, live-jslm (RBL; REBYOTA™), the first microbiota-based live biotherapeutic approved by the US Food and Drug Administration to prevent recurrent Clostridioides difficile infection (rCDI) in adults, has been evaluated in 5 prospective clinical trials. A retrospective analysis considered the safety and efficacy of RBL administered under US Food and Drug Administration enforcement discretion to patients with rCDI and broad eligibility criteria mimicking real-world practice.

Methods

We retrospectively identified adults with rCDI treated with RBL under enforcement discretion between November 1, 2015, and September 30, 2019, across 5 study sites. CDI diagnosis was based on site-specific practice. The primary safety set (PSS) included all patients who were naïve to previous RBL treatment and had continuously comprehensive medical records for 6 months following treatment.

Results

The primary treatment cohort had 94 patients; the PSS included 64 patients with common comorbidities receiving diverse chronic therapeutics. Most treatment-emergent adverse events were mild to moderate in severity and comparable between comorbidity subgroups and the overall population. There were no serious adverse events related to RBL or the administration procedure. In the PSS, 82.8% of RBL-treated patients responded at 8 weeks, of whom 88.7% had sustained response through 6 months. The number of RBL doses administered had no marked effect on outcome.

Conclusions

Together with prospective clinical trial outcomes, these findings support the efficacy and safety of RBL to prevent rCDI, with diagnostics and comorbidities representative of real-world clinical practice.

Delivery of Fecal Material to Terminal Ileum Is Associated with Long-Term Success of Fecal Microbiota Transplantation

BACKGROUND

Fecal microbiota transplantation (FMT) is a highly effective treatment for recurrent Clostridioides difficile infection (CDI). However, 10-20% of patients still fail to recover following FMT. There is a need to understand why these failures occur and if there are modifiable factors that can be addressed by clinicians performing FMT.

AIMS

We sought to identify factors related to the FMT procedure itself which could impact FMT outcomes. We also aimed to identify patient demographics which might be associated with FMT outcomes and whether any factors were associated with early FMT failure compared to late CDI recurrence.

METHODS

We performed a retrospective multicenter cohort analysis of FMT procedures between October 2005 and November 2020. We collected data on patient demographics, details of the FMT procedure, and procedure outcomes. Using univariate and multivariate regression, we evaluated whether these factors were associated with long-term FMT success, early FMT failure (less than 60 days following procedure), or late CDI recurrence (more than 60 days following procedure).

RESULTS

Long-term success of FMT was strongly correlated with any delivery of stool to the terminal ileum (Odds Ratio [OR] 4.83, 95% confidence interval [CI] 1.359-17.167) and underlying neurologic disease (OR 8.012, 95% CI 1.041-61.684). Lower bowel prep quality was significantly associated with both early FMT failure (p = 0.034) and late CDI recurrence (p = 0.050).

CONCLUSIONS

Delivery of stool to the terminal ileum is significantly associated with long-term success following FMT. This is a relatively safe practice which could easily be incorporated into the standard of care for colonoscopic FMT.

In Silico Analysis of Changes in Predicted Metabolic Capabilities of Intestinal Microbiota after Fecal Microbial Transplantation for Treatment of Recurrent Clostridioides difficile Infection

IMPORTANCE

Although highly effective in treating recurrent Clostridioides difficile infection (RCDI), the mechanisms of action of fecal microbial transplantation (FMT) are not fully understood.

AIM

The aim of this study was to explore microbially derived products or pathways that could contribute to the therapeutic efficacy of FMT.

METHODS

Stool shotgun metagenomic sequencing data from 18 FMT-treated RCDI patients at 4 points in time were used for the taxonomic and functional profiling of their gut microbiome. The abundance of the KEGG orthology (KO) groups was subjected to univariate linear mixed models to assess the significance of the observed differences between 0 (pre-FMT), 1, 4, and 12 weeks after FMT.

RESULTS

Of the 59,987 KO groups identified by shotgun metagenomic sequencing, 27 demonstrated a statistically significant change after FMT. These KO groups are involved in many cellular processes, including iron homeostasis, glycerol metabolism, and arginine regulation, all of which have been implicated to play important roles in bacterial growth and virulence in addition to modulating the intestinal microbial composition.

CONCLUSION

Our findings suggest potential changes in key KO groups post-FMT, which may contribute to FMT efficacy beyond the restored microbial composition/diversity and metabolism of bile acids and short-chain fatty acids. Future larger studies that include a fecal metabolomics analysis combined with animal model validation work are required to further elucidate the molecular mechanisms.

Faecal Microbiota Transplantation is a simple, effective and safe treatment in the management of C. difficile infection in daily clinical practice

INTRODUCTION

Faecal microbiota transplantation (FMT) is a treatment supported by wide scientific evidence and proved to be very effective in the management of Clostridioides difficile infection (CDI). The objective of this study is to analyze its effectiveness and safety in a real clinical practice setting.

METHODS

Retrospective, single-center and descriptive observational study in which all FMT performed between May 2016 and December 2020 were included. Technical success was defined as the successful administration of the faecal preparation in the patient's gastrointestinal tract and clinical success the disappearance of diarrhoea in the first 72 h after the procedure with no relapse within the following 8 weeks after the therapy was started.

RESULTS

15 FMT were performed in 13 patients. Median age was 79 years (range: 40-98 years); being 60% women and 33.3% depedent persons. The indication for FMT was recurrent CDI in 84.6%. All FMTs were performed by colonoscopy and from related donors. With a first procedure, the FMT was effective in 11 of 13 patients (84.61%; 95% CI; 54.55-98.07). Time until resolution of symptoms was less than 48 h in all cases. Post-transplant follow-up was 25.66 ± 17.5 months. No significant short or long-term complications were recorded at follow-up.

CONCLUSION

TMF is a simple, effective and safe procedure in CD infection, even in elderly patients or those with great comorbidities.

Outcomes of Fecal Microbiota Transplantation for C. difficile Infection in Inflammatory Bowel Disease : A Systematic Review and Meta-analysis

BACKGROUND

Fecal microbiota transplantation (FMT) is a safe and effective therapy for recurrent Clostridioides difficile infection (CDI). Data on FMT for CDI in patients with underlying inflammatory bowel disease (IBD) are emerging but conflicting. We performed a systematic review and meta-analysis to describe the efficacy and safety of FMT for CDI in IBD and its impact on IBD outcomes.

METHODS

A systematic search of multiple databases including Embase, Scopus, and Web of Science was performed. Our primary analysis focused on pooled rate of CDI resolution after single and multiple FMTs in IBD patients. Additional analyses included rates of IBD-associated outcomes (flare, surgery, symptom improvement) after FMT. The random-effects model was used to calculate pooled rates.

RESULTS

Among 457 adult patients, 363 had CDI resolution after first FMT with a pooled cure rate of 78% [95% confidence interval (CI): 73%-83%; I2 =39%]. Overall pooled rate cure rate with single and multiple FMTs was 88% (95% CI: 81%-94%; I2 =73%). The pooled rate of an IBD flare after FMT was 26.8% (95% CI: 22.5%-31.6%; I2 =9%) and of colectomy was 7.3% (95% CI: 4.7%-10.5%; I2 =56%). Among 141 pediatric patients, 106 had CDI resolution after first FMT with pooled cure rate of 78% (95% CI: 58%-93%; I2 =59%). Overall pooled cure rate with single and multiple FMTs was 77% (95% CI: 50%-96%; I2 =63%). The pooled rate of an IBD flare after FMT was 10.8% (95% CI: 5.7%-18.5% I2 =43%), and of colectomy was 10.3% (95% CI: 2.1%-30.2% I2 =23%).

CONCLUSIONS

FMT appears to be a highly effective therapy for preventing recurrent CDI in patients with IBD. Patients who fail a single FMT may benefit from multiple FMTs.

Controversies in the Prevention and Treatment of Clostridioides difficile Infection in Adults: A Narrative Review

Clostridioides difficile remains a problematic pathogen resulting in significant morbidity and mortality, especially for high-risk groups that include immunocompromised patients. Both the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America (IDSA/SHEA), as well as the American College of Gastroenterology (ACG) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) recently provided guideline updates for C. difficile infection (CDI). In this narrative review, the authors reviewed available literature regarding the prevention or treatment of CDI in adults and focused on disagreements between the IDSA/SHEA and ACG guidelines, as well as articles that have been published since the updates. Several options for primary prophylaxis are available, including probiotics and antibiotics (vancomycin, fidaxomicin). The literature supporting fidaxomicin is currently quite limited. While there are more studies evaluating probiotics and vancomycin, the optimal patient populations and regimens for their use have yet to be defined. While the IDSA/SHEA guidelines discourage metronidazole use for mild CDI episodes, evidence exists that it may remain a reasonable option for these patients. Fidaxomicin has an advantage over vancomycin in reducing recurrences, but its use is limited by cost. Despite this, recent studies suggest fidaxomicin's cost-effectiveness as a first-line therapy, though this is highly dependent on institutional contracts and payment structures. Secondary prophylaxis should focus on non-antimicrobial options to lessen the impact on the microbiome. The oral option of fecal microbiota transplantation (FMT), SER109, and the now FDA-approved RBX2660 represent exciting new options to correct dysbiosis. Bezlotoxumab is another attractive option to prevent recurrences. Further head-to-head studies of newer agents will be needed to guide selection of the optimal therapies for CDI primary and secondary prophylaxis.

From signal transduction to protein toxins-a narrative review about milestones on the research route of C. difficile toxins

Selected findings about Clostridioides difficile (formerly Clostridium difficile) toxins are presented in a narrative review. Starting with a personal view on research about G proteins, adenylyl cyclase, and ADP-ribosylating toxins in the laboratory of Günter Schultz in Heidelberg, milestones of C. difficile toxin research are presented with the focus on toxin B (TcdB), covering toxin structure, receptor binding, toxin up-take and refolding, the intracellular actions of TcdB, and the treatment of C. difficile infection.

Fecal Microbiota Transplantation Research over the Past Decade: Current Status and Trends

Background

Fecal microbiota transplantation (FMT) is a current research hotspot, with a surge in the output of publications over the past decade. This study dedicates to the exploration of the research status and highlights significant themes and future trends in FMT research with the aid of bibliometric analysis.

Methods

FMT publications from 2012 to 2021 were retrieved on August 12, 2022, using the SCI-Expanded of Web of Science (WoS). The Bibliometrix in R program, Microsoft Office Excel, VOSviewer, and CiteSpace were utilized for bibliometrics and visual analysis, revealing the main publications, journals, countries, agencies, authors, and keywords distribution in FMT research.

Results

There were 2,931 papers included. FMT research presented a growing trend from 2012 to 2021. The countries with the most publications and contributions in FMT area were China and the United States. The high-yield institutions were Harvard University, Udice French Research Universities, and the University of California System. The primary authors were Nieuwdorp Max, Allegretti Jessica R, and Kassam Zain. Frontiers in Microbiology and Science were the top-ranked journals in publications and total citations, respectively. The important topics primarily included FMT-related mechanisms and the usage of FMT in Clostridium difficile infection (CDI), inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), metabolic disease, neurological disorders, and psychiatric disorders. Future research would primarily concentrate on neurological disorders, chemotherapy and immunotherapy for malignant tumors, and FMT-related consensus and guidelines.

Conclusion

With the help of bibliometric analysis, we were able to obtain the understanding of the status and trends of global FMT-related research. The field of FMT is undergoing tremendous progress, and our findings can guide clinical researchers' and practitioners' future work in the rapidly evolving field of FMT.

Gut microbiota and microbiota-based therapies for Clostridioides difficile infection

Clostridioides difficile infection poses significant clinical challenges due to its recurrent nature. Current antibiotic management does not address the underlying issue, that of a disturbed gastrointestinal microbiome, called dysbiosis. This provides a supportive environment for the germination of C. difficile spores which lead to infection and toxin production as well as an array of other health conditions. The use of microbiome restoration therapies such as live biotherapeutics can reverse dysbiosis and lead to good clinical outcomes. Several such therapies are under clinical investigation.

Gut microbiota changes associated with Clostridioides difficile infection and its various treatment strategies

Human gut microbiota are critical to both the development of and recovery from Clostridioides difficile infection (CDI). Antibiotics are the mainstay of CDI treatment, yet inherently cause further imbalances in the gut microbiota, termed dysbiosis, complicating recovery. A variety of microbiota-based therapeutic approaches are in use or in development to limit disease- and treatment-associated dysbiosis and improve rates of sustained cure. These include the recently FDA-approved fecal microbiota, live-jslm (formerly RBX2660) and fecal microbiota spores, live-brpk (formerly SER-109), which represent a new class of live biotherapeutic products (LBPs), traditional fecal microbiota transplantation (FMT), and ultra-narrow-spectrum antibiotics. Here, we aim to review the microbiome changes associated with CDI as well as a variety of microbiota-based treatment approaches.

The Role of Microbiome-Based Therapeutics in Clostridioides difficile Infection: Durable, Long-Term Results of RBX2660

A recently published manuscript described findings from a phase 2 open label study of the microbiota-based live biotherapeutic product RBX2660 in patients with two or more previous recurrent Clostridioides difficile infection (rCDI) episodes, and described long-term safety and sustained treatment success through 24 months. As previous studies have typically focused on short-term clinical outcomes, these new data provide insight into the tolerability, safety, and efficacy of RBX2660 over the long term. When microbiota-based products were first evaluated, the long-term efficacy and safety were principal concerns of the United States Food and Drug Administration. Microbiota-based live biotherapeutic products (LBPs) represent an emerging approach to the management of CDI and perhaps other gastrointestinal and medical conditions whose pathogenesis is defined by microbial dysbiosis. RBX2660 is a human-derived, broad consortium microbiota-based LBP that consists of a population of microbes obtained from healthy stool donors and may reflect the symbiotic nature of a healthy colonic microbiome. RBX2660 is rectally administered and does not require sedation or special preparation of the recipient. Potential advantages of the rectal administration of RBX2660 include the ease of administration and lack of need for any bowel preparation, which may benefit those who are frail, have swallowing issues, or cannot take bowel laxative preparations. In this multicenter prospective trial of rCDI, patients who achieved treatment success 8 weeks after receiving RBX2660 continued to have a sustained clinical response over the course of long-term follow-up, with more than 90% of treatment responders remaining CDI-free at 6, 12, and 24 months. Following receipt of RBX2660, the gut microbiota of those with treatment success were restored from a dysbiotic state to become more diverse and similar to RBX2660 composition. The restoration of the microbiota occurred as early as 7 days after RBX2660 administration and remained stable through the 24-month analysis. No new adverse outcomes were observed during the prospective assessment, and the safety profile of RBX2660 was consistent with previous studies. Based on the clinical studies, RBX2660 will most likely benefit those with ≥ 1 rCDI episode or those who are at a high risk of subsequent rCDI, such as patients who have comorbid conditions including renal disease, heart disease, or inflammatory bowel disease, or who are immunosuppressed. The role of microbiome-based therapeutics in 47 Clostridioides difficile infection: Durable, long-term results of RBX2660 (MP4 511833 KB).

Microbiome therapeutics for the treatment of recurrent Clostridioides difficile infection

INTRODUCTION

The gut microbiome is implicated in Clostridioides difficile infection (CDI) and recurrent CDI (rCDI).

AREAS COVERED

This review covers the mechanisms by which microbiome therapeutics treat rCDI, their efficacy and safety, and clinical trial design considerations for future research.

EXPERT OPINION

Altering the chemical environment of the gut and reconstituting colonization resistance is a promising strategy for preventing and treating rCDI. Fecal microbiota transplant (FMT) is safe and effective for the treatment of rCDI. However, limitations of FMT have prompted investigation into alternative microbiome therapeutics. These alternative microbiome therapies require further evaluation, and adaptive trial designs should be strongly considered to more rapidly discern variables including the need for bowel preparation, timing and selection of pre-treatment antibiotics, and dose and duration of microbiome therapeutics. A broad range of adverse events must be prospectively evaluated in these controlled trials, as microbiome therapeutics have the potential for numerous effects. Future studies will lead to a greater understanding of the mechanisms by which microbiome therapies can break the cycle of rCDI, which should ultimately yield a personalized approach to rCDI treatment that restores an individual's specific deficit(s) in colonization resistance to C. difficile.

The role of the gut microbiome in colonization resistance and recurrent Clostridioides difficile infection

The species composition of the human gut microbiota is related to overall health, and a healthy gut microbiome is crucial in maintaining colonization resistance against pathogens. Disruption of gut microbiome composition and functionality reduces colonization resistance and has been associated with several gastrointestinal and non-gastrointestinal diseases. One prime example is Clostridioides difficile infection (CDI) and subsequent recurrent infections that occur after the development of systemic antibiotic-related dysbiosis. Standard-of-care antibiotics used for both acute and recurrent infections do not address dysbiosis and often worsen the condition. Moreover, monoclonal antibodies, recommended in conjunction with standard-of-care antibiotics for the prevention of recurrent CDI in patients at high risk of recurrence, reduce recurrences but do not address the underlying dysbiosis. Fecal microbiota transplantation (FMT) is an evolving therapeutic strategy in which microbes are harvested from healthy donor stool and transplanted into the gut of a recipient to restore the gut microbiome. Although effective in the prevention of recurrent CDI, some existing challenges include screening and the standardization of stool acquisition and processing. Recent safety alerts by the US Food and Drug Administration raised concern about the possibility of transmission of multidrug-resistant organisms or severe acute respiratory syndrome coronavirus 2 via FMT. Increased knowledge that microbes are beneficial in restoring the gut microbiome has led to the clinical development of several newer biotherapeutic formulations that are more regulated than FMT, which may allow for improved restoration of the gut microbiome and prevention of CDI recurrence. This review focuses on mechanisms by which gut microbiome restoration could influence colonization resistance against the pathogen C. difficile.

Plain language summary

The Role of the Gut Microbiome in Clostridioides difficile Infection Introduction: A rich and diverse gut microbiome is key to immune system regulation and colonization resistance against pathogens.A disruption in the gut microbiome composition can make the gut more vulnerable to diseases such as Clostridioides difficile infection (CDI), caused by the bacterium C. difficile.CDI management presents a therapeutic dilemma, as it is usually treated with antibiotics that can treat the infection but also can damage the microbiome.Treatment of CDI using antibiotics can further reduce microbial diversity and deplete beneficial bacteria from the gut leading to a condition called dysbiosis.Antibiotic treatment can be followed by therapies that restore the gut microbiota, boost colonization resistance, and prevent the development of antimicrobial resistance.It is important to evaluate treatment options to determine their safety and effectiveness. Methods: The researchers provided an overview of the mechanisms that the gut microbiome uses to prevent colonization of the gut by pathogens.They subsequently reviewed the efficacy and shortcomings of the following treatments for CDI: - Antibiotics- Monoclonal antibodies- Fecal microbiota transplantation (FMT) Results: Commensal intestinal bacteria prevent colonization of the gut by pathogens using mechanisms such as: - Competition for key nutrients- Production of inhibitory bile acids- Short-chain fatty acid production- Lowering the luminal pH- Production of bacteriocinsAntibiotic therapy is recommended as a standard treatment for CDI. However, patients are vulnerable to recurrent CDI after discontinuation of the therapy.Monoclonal antibodies that inactivate C. difficile toxins may be recommended along with antibiotics to prevent recurrent CDI. However, this approach does not restore the microbiome.FMT is one method of microbial restoration, where stool is harvested from a healthy donor and transplanted into a patient's colon.Although FMT has shown some efficacy in the treatment of recurrent CDI, the procedure is not standardized.Safety concerns have been raised about the possibility of transmission of multidrug-resistant pathogens via FMT. Conclusion: Treatment methods that can efficiently restore the diversity of the gut microbiome are crucial in preventing recurrence of CDI.

Gut Microbiota and Clostridium difficile: What We Know and the New Frontiers

Our digestive system, particularly our intestines, harbors a vast amount of microorganisms, whose genetic makeup is referred to as the microbiome. Clostridium difficile is a spore-forming Gram-positive bacterium, which can cause an infection whose symptoms range from asymptomatic colonization to fearsome complications such as the onset of toxic megacolon. The relationship between gut microbiota and Clostridium difficile infection has been studied from different perspectives. One of the proposed strategies is to be able to specifically identify which types of microbiota alterations are most at risk for the onset of CDI. In this article, we understood once again how crucial the role of the human microbiota is in health and especially how crucial it becomes, in the case of its alteration, for the individual's disease. Clostridium difficile infection is an emblematic example of how a normal and physiological composition of the human microbiome can play a very important role in immune defense against such a fearsome disease.

Cost-effectiveness of Fecal Microbiota Transplantation for First Recurrent Clostridioides difficile Infection

BACKGROUND

Both the American College of Gastroenterology and the Infectious Diseases Society of America (IDSA)/Society for Healthcare Epidemiology of America 2021 Clostridioides difficile infection (CDI) guidelines recommend fecal microbiota transplantation (FMT) for persons with multiple recurrent CDI. Emerging data suggest that FMT may have high cure rates when used for first recurrent CDI. The aim of this study was to assess the cost-effectiveness of FMT for first recurrent CDI.

METHODS

We developed a Markov model to simulate a cohort of patients presenting with initial CDI infection. The model estimated the costs, effectiveness, and cost-effectiveness of different CDI treatment regimens recommended in the 2021 IDSA guidelines, with the additional option of FMT for first recurrent CDI. The model includes stratification by the severity of initial infection, estimates of cure, recurrence, and mortality. Data sources were taken from IDSA guidelines and published literature on treatment outcomes. Outcome measures were quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs).

RESULTS

When FMT is available for first recurrent CDI, the optimal cost-effective treatment strategy is fidaxomicin for initial nonsevere CDI, vancomycin for initial severe CDI, and FMT for first and subsequent recurrent CDI, with an ICER of $27 135/QALY. In probabilistic sensitivity analysis at a $100 000 cost-effectiveness threshold, FMT for first and subsequent CDI recurrence was cost-effective 90% of the time given parameter uncertainty.

CONCLUSIONS

FMT is a cost-effective strategy for first recurrent CDI. Prospective evaluation of FMT for first recurrent CDI is warranted to determine the efficacy and risk of recurrence.

The Role of Gut Microbiota and Trimethylamine N-oxide in Cardiovascular Diseases

Changes in the intestinal flora and its metabolites have been associated with cardiovascular disease (CVD). Short-chain fatty acids, bile acids, and especially trimethylamine N-oxide (TMAO), an endothelial toxic factor produced by gut microbiota from phosphatidylcholine in meat, have been identified to be closely related to endothelial cell dysfunction as well as tightly affiliated with CVD, the two main types being coronary artery disease (CAD) and coronary microvascular disease (CMVD). We discuss how changes in the gut flora and the metabolite TMAO contribute to the development of CAD and CMVD. The above insight might serve as a stepping stone for novel CAD and CMVD diagnostics and therapies centered on microbiota.