Efficacy and Safety of RBX2660 in PUNCH CD3, a Phase III, Randomized, Double-Blind, Placebo-Controlled Trial with a Bayesian Primary Analysis for the Prevention of Recurrent Clostridioides difficile Infection

Reduction of product composition variability using pooled microbiome ecosystem therapy and consequence in two infectious murine models

Growing evidence demonstrates the key role of the gut microbiota in human health and disease. The recent success of microbiotherapy products to treat recurrent Clostridioides difficile infection has shed light on its potential in conditions associated with gut dysbiosis, such as acute graft-versus-host disease, intestinal bowel diseases, neurodegenerative diseases, or even cancer. However, the difficulty in defining a "good" donor as well as the intrinsic variability of donor-derived products' taxonomic composition limits the translatability and reproducibility of these studies. Thus, the pooling of donors' feces has been proposed to homogenize product composition and achieve higher taxonomic richness and diversity. In this study, we compared the metagenomic profile of pooled products to corresponding single donor-derived products. We demonstrated that pooled products are more homogeneous, diverse, and enriched in beneficial bacteria known to produce anti-inflammatory short chain fatty acids compared to single donor-derived products. We then evaluated pooled products' efficacy compared to corresponding single donor-derived products in Salmonella and C. difficile infectious mouse models. We were able to demonstrate that pooled products decreased pathogenicity by inducing a structural change in the intestinal microbiota composition. Single donor-derived product efficacy was variable, with some products failing to control disease progression. We further performed in vitro growth inhibition assays of two extremely drug-resistant bacteria, Enterococcus faecium vanA and Klebsiella pneumoniae oxa48, supporting the use of pooled microbiotherapies. Altogether, these results demonstrate that the heterogeneity of donor-derived products is corrected by pooled fecal microbiotherapies in several infectious preclinical models.IMPORTANCEGrowing evidence demonstrates the key role of the gut microbiota in human health and disease. Recent Food and Drug Administration approval of fecal microbiotherapy products to treat recurrent Clostridioides difficile infection has shed light on their potential to treat pathological conditions associated with gut dysbiosis. In this study, we combined metagenomic analysis with in vitro and in vivo studies to compare the efficacy of pooled microbiotherapy products to corresponding single donor-derived products. We demonstrate that pooled products are more homogeneous, diverse, and enriched in beneficial bacteria compared to single donor-derived products. We further reveal that pooled products decreased Salmonella and Clostridioides difficile pathogenicity in mice, while single donor-derived product efficacy was variable, with some products failing to control disease progression. Altogether, these findings support the development of pooled microbiotherapies to overcome donor-dependent treatment efficacy.

Critical role of the gut microbiota in immune responses and cancer immunotherapy

The gut microbiota plays a critical role in the progression of human diseases, especially cancer. In recent decades, there has been accumulating evidence of the connections between the gut microbiota and cancer immunotherapy. Therefore, understanding the functional role of the gut microbiota in regulating immune responses to cancer immunotherapy is crucial for developing precision medicine. In this review, we extract insights from state-of-the-art research to decipher the complicated crosstalk among the gut microbiota, the systemic immune system, and immunotherapy in the context of cancer. Additionally, as the gut microbiota can account for immune-related adverse events, we discuss potential interventions to minimize these adverse effects and discuss the clinical application of five microbiota-targeted strategies that precisely increase the efficacy of cancer immunotherapy. Finally, as the gut microbiota holds promising potential as a target for precision cancer immunotherapeutics, we summarize current challenges and provide a general outlook on future directions in this field.

Breaking the Cycle of Recurrent Clostridioides difficile Infections: A Narrative Review Exploring Current and Novel Therapeutic Strategies

Clostridioides difficile is a toxin-producing bacteria that is a main cause of antibiotic-associated diarrhea. Clostridioides difficile infections (CDI) are associated with disruptions within the gastrointestinal (GI) microbiota which can be further exacerbated by CDI-targeted antibiotic treatment thereby causing recurrent CDI (rCDI) and compounding the burden placed on patients and the healthcare system. Treatment of rCDI consists of antibiotics which can be paired with preventative therapeutics, such as bezlotoxumab or fecal microbiota transplants (FMTs), if sustained clinical response is not obtained. Newer preventative strategies have been recently approved to assist in restoring balance within the GI system with the goal of preventing recurrent infections.

A Comparison of Currently Available and Investigational Fecal Microbiota Transplant Products for Recurrent Clostridioides difficile Infection

Clostridioides difficile infection (CDI) is an intestinal infection that causes morbidity and mortality and places significant burden and cost on the healthcare system, especially in recurrent cases. Antibiotic overuse is well recognized as the leading cause of CDI in high-risk patients, and studies have demonstrated that even short-term antibiotic exposure can cause a large and persistent disturbance to human colonic microbiota. The recovery and sustainability of the gut microbiome after dysbiosis have been associated with fewer CDI recurrences. Fecal microbiota transplantation (FMT) refers to the procedure in which human donor stool is processed and transplanted to a patient with CDI. It has been historically used in patients with pseudomembranous colitis even before the discovery of Clostridioides difficile. More recent research supports the use of FMT as part of the standard therapy of recurrent CDI. This article will be an in-depth review of five microbiome therapeutic products that are either under investigation or currently commercially available: Rebyota (fecal microbiota, live-jslm, formerly RBX2660), Vowst (fecal microbiota spores, live-brpk, formerly SER109), VE303, CP101, and RBX7455. Included in this review is a comparison of the products' composition and dosage forms, available safety and efficacy data, and investigational status.

Protection against Clostridioides difficile disease by a naturally avirulent C. difficile strain

Clostridioides difficile (C. difficile) strains belonging to the epidemic BI/NAP1/027 (RT027) group have been associated with increased transmissibility and disease severity. In addition to the major toxin A and toxin B virulence factors, RT027 strains also encode the CDT binary toxin. Our lab previously identified a toxigenic RT027 isolate, ST1-75, that is avirulent in mice despite densely colonizing the colon. Here, we show that co-infecting mice with the avirulent ST1-75 and virulent R20291 strains protects mice from colitis due to rapid clearance of the virulent strain and persistence of the avirulent strain. Although avirulence of ST1-75 is due to a mutation in the cdtR gene, which encodes a response regulator that modulates the production of all three C. difficile toxins, the ability of ST1-75 to protect against acute colitis is not directly attributable to the cdtR mutation. Metabolomic analyses indicate that the ST1-75 strain depletes amino acids more rapidly than the R20291 strain and supplementation with amino acids ablates ST1-75's competitive advantage, suggesting that the ST1-75 strain limits the growth of virulent R20291 bacteria by amino acid depletion. Since the germination kinetics and sensitivity to the co-germinant glycine are similar for the ST1-75 and R20291 strains, our results identify the rapidity of in vivo nutrient depletion as a mechanism providing strain-specific, virulence-independent competitive advantages to different BI/NAP1/027 strains. They also suggest that the ST1-75 strain may, as a biotherapeutic agent, enhance resistance to CDI in high-risk patients.

Importance

Clostridioides difficile infections (CDI) are prevalent in healthcare settings and are associated with high recurrence rates. Therapies to prevent CDI, including recent FDA-approved live biotherapeutic products, are costly and have not been used to prevent primary infections. While a nontoxigenic C. difficile strain (NTCD-M3) protects against virulent CDI in animals and reduced CDI recurrence in a phase 2 clinical trial, protection against CDI recurrence in humans was variable and required high doses of the nontoxigenic strain. Here we show that an avirulent C. difficile isolate, ST1-75, efficiently outcompetes virulent C. difficile strains in mice when co-infected at a 1:1 ratio. Our data suggest that inter-strain competition results from ST1-75's more rapid depletion of amino acids than the virulent R20291 strain. Our study identifies inter-strain nutrient depletion as a potentially exploitable mechanism to reduce the incidence of CDI.

Estimating excess mortality and economic burden of Clostridioides difficile infections and recurrences during 2015-2019: The RECUR England study

OBJECTIVES

To generate real-world evidence on all-cause mortality and economic burden of Clostridioides difficile infections (CDIs) and recurrences (rCDIs) in England.

METHODS

We conducted a cohort study using retrospective data from Clinical Practice Research Datalink linked to Hospital Episode Statistics. Patients diagnosed with CDI in hospital and community settings during 2015-2018 were included and followed for ≥1 year. All-cause mortality was described at 6, 12, and 24 months. Healthcare resource usage (HCRU) and associated costs were assessed at 12 months of follow-up. A cohort of non-CDI patients, matched by demographic and clinical characteristics including Charlson Comorbidity Index score, was used to assess excess mortality and incremental costs of HCRU.

RESULTS

All-cause mortality among CDI patients at 6, 12, and 24 months was 15.87%, 20.37%, and 27.03%, respectively. A higher proportion of rCDI patients died at any point during follow-up. Compared with matched non-CDI patients, excess mortality was highest at 6 months with 1.81 and 2.53 deaths per 100 patient-months among CDI and ≥1 rCDI patients. Hospitalizations were the main drivers of costs, with an incremental cost of £1209.21 per CDI patient. HCRU and costs increased with rCDIs.

CONCLUSION

CDI poses a substantial mortality and economic burden, further amplified by rCDIs.

Microbiota therapeutics for inflammatory bowel disease: the way forward

Microbiota therapeutics that transplant faecal material from healthy donors to people with mild-to-moderate ulcerative colitis have shown the potential to induce remission in about 30% of participants in small, phase 2 clinical trials. Despite this substantial achievement, the field needs to leverage the insights gained from these trials and progress towards phase 3 clinical trials and drug approval, while identifying the distinct clinical niche for this new therapeutic modality within inflammatory bowel disease (IBD) therapeutics. We describe the lessons that can be learned from past studies of microbiota therapeutics, from full spectrum donor stool to defined products manufactured in vitro. We explore the actionable insights these lessons provide on the design of near-term studies and future trajectories for the integration of microbiota therapeutics in the treatment of IBD. If successful, microbiota therapeutics will provide a powerful orthogonal approach (complementing or in combination with existing immunomodulatory drugs) to raise the therapeutic ceiling for the many non-responders and partial responders within the IBD patient population.

Next generation probiotics: Engineering live biotherapeutics

The population dynamics of the human microbiome have been associated with inflammatory bowel disease, cancer, obesity, autoimmune diseases, and many other human disease states. An emerging paradigm in treatment is the administration of live engineered organisms, also called next-generation probiotics. However, the efficacy of these microbial therapies can be limited by the organism's overall performance in the harsh and nutrient-limited environment of the gut. In this review, we summarize the current state of the art use of bacterial and yeast strains as probiotics, highlight the recent development of genetic tools for engineering new therapeutic functions in these organisms, and report on the latest therapeutic applications of engineered probiotics, including recent clinical trials. We also discuss the supplementation of prebiotics as a method of manipulating the microbiome and improving the overall performance of engineered live biotherapeutics.

Fine-tuning the gut ecosystem: the current landscape and outlook of artificial microbiome therapeutics

The gut microbiome is acknowledged as a key determinant of human health, and technological progress in the past two decades has enabled the deciphering of its composition and functions and its role in human disorders. Therefore, manipulation of the gut microbiome has emerged as a promising therapeutic option for communicable and non-communicable disorders. Full exploitation of current therapeutic microbiome modulators (including probiotics, prebiotics, and faecal microbiota transplantation) is hindered by several factors, including poor precision, regulatory and safety issues, and the impossibility of providing reproducible and targeted treatments. Artificial microbiota therapeutics (which include a wide range of products, such as microbiota consortia, bacteriophages, bacterial metabolites, and engineered probiotics) have appeared as an evolution of current microbiota modulators, as they promise safe and reproducible effects, with variable levels of precision via different pathways. We describe the landscape of artificial microbiome therapeutics, from those already on the market to those still in the pipeline, and outline the major challenges for positioning these therapeutics in clinical practice.

Assessing Engraftment Following Fecal Microbiota Transplant

Fecal Microbiota Transplant (FMT) is an FDA approved treatment for recurrent Clostridium difficile infections, and is being explored for other clinical applications, from alleviating digestive and neurological disorders, to priming the microbiome for cancer treatment, and restoring microbiomes impacted by cancer treatment. Quantifying the extent of engraftment following an FMT is important in determining if a recipient didn't respond because the engrafted microbiome didn't produce the desired outcomes (a successful FMT, but negative treatment outcome), or the microbiome didn't engraft (an unsuccessful FMT and negative treatment outcome). The lack of a consistent methodology for quantifying FMT engraftment extent hinders the assessment of FMT success and its relation to clinical outcomes, and presents challenges for comparing FMT results and protocols across studies. Here we review 46 studies of FMT in humans and model organisms and group their approaches for assessing the extent to which an FMT engrafts into three criteria: 1) Chimeric Asymmetric Community Coalescence investigates microbiome shifts following FMT engraftment using methods such as alpha diversity comparisons, beta diversity comparisons, and microbiome source tracking. 2) Donated Microbiome Indicator Features tracks donated microbiome features (e.g., amplicon sequence variants or species of interest) as a signal of engraftment with methods such as differential abundance testing based on the current sample collection, or tracking changes in feature abundances that have been previously identified (e.g., from FMT or disease-relevant literature). 3) Temporal Stability examines how resistant post-FMT recipient's microbiomes are to reverting back to their baseline microbiome. Individually, these criteria each highlight a critical aspect of microbiome engraftment; investigated together, however, they provide a clearer assessment of microbiome engraftment. We discuss the pros and cons of each of these criteria, providing illustrative examples of their application. We also introduce key terminology and recommendations on how FMT studies can be analyzed for rigorous engraftment extent assessment.

Update on microbiota-derived therapies for recurrent Clostridioides difficile infections

BACKGROUND

Faecal microbiota transplantation (FMT) is the standard treatment for patients with multiple recurrent Clostridioides difficile infection (rCDI). Recently, new commercially developed human microbiota-derived medicinal products have been evaluated and Food and Drug Administration-approved with considerable differences in terms of composition, administration, and targeted populations.

OBJECTIVES

To review available data on the different microbiota-derived treatments at the stage of advanced clinical evaluation and research in rCDI in comparison with FMT.

SOURCES

Phase II or III trials evaluating a microbiota-derived medicinal product to prevent rCDI.

CONTENT

Two commercial microbiota-derived medicinal products are approved by the Food and Drug Administration: Rebyota (RBX2660 Ferring Pharmaceuticals, marketed in the United States) and VOWST (SER-109 -Seres Therapeutics, marketed in the United States), whereas VE303 (Vedanta Biosciences Inc) will be studied in phase III trial. RBX2660 and SER-109 are based on the processing of stools from healthy donors, whereas VE303 consists of a defined bacterial consortium originating from human stools and produced from clonal cell banks. All have proven efficacy to prevent rCDI compared with placebo in patients considered at high risk of recurrence. However, the heterogeneity of the inclusion criteria, and the time between each episode and CDI diagnostics makes direct comparison between trials difficult. The differences regarding the risk of recurrence between the treatment and placebo arms were lower than previously described for FMT (FMT: Δ = 50.5%; RBX2660-phase III: Δ = 13.1%; SER-109-phase III: Δ = 28%; high-dose VE303-phase-II: Δ = 31.7%). All treatments presented a good overall safety profile with mainly mild gastrointestinal symptoms.

IMPLICATIONS

Stool-derived products and bacterial consortia need to be clearly distinguished in terms of product characterization and their associated risks with specific long-term post-marketing evaluation similar to registries used for FMT. Their place in the therapeutic strategy for patients with rCDI requires further studies to determine the most appropriate patient population and administration route to prevent rCDI.

Microbiota-Based Therapeutics as New Standard-of-Care Treatment for Recurrent Clostridioides difficile Infection

Background

Clostridioides difficile (C. difficile) is a spore-forming bacterial species that ubiquitously exists in the environment. Colonization by C. difficile is highly prevalent in infants, while fewer than 5% of adults are asymptomatic carriers. Disruption of the microbiome, such as through antibiotic treatment, triggers the germination of bacterial spores into numerous vegetative cells. These cells then produce enterotoxins that result in watery diarrhea and colonic inflammation. If left untreated, C. difficile infection (CDI) can lead to pseudomembranous colitis with the potentially life-threatening complication of toxic megacolon.

Summary

Over the past few decades, the incidence, morbidity, and mortality associated with CDIs have increased. They have emerged as the primary cause of nosocomial gastrointestinal infections in industrialized countries, posing a significant burden on healthcare systems. Despite antibiotics often being the cause of CDIs, they remain the standard treatment. However, a considerable number of patients treated with antibiotics will experience recurrent CDI (rCDI). Microbiota-based therapies targeting the core issue of CDI - antibiotic-induced dysbiosis - hold promise for rCDI treatment. While data for probiotics are insufficient, numerous studies have highlighted the effectiveness of fecal microbiota transplantation (FMT) as a safe and viable therapeutic option for rCDI. This approach is now endorsed by multiple guidelines. Nonetheless, regulatory prerequisites, such as comprehensive stool donor screening, restrict the widespread adoption of FMT beyond specialized centers. Recently, the US Food and Drug Administration has approved two commercial microbiota-based therapeutics to prevent CDI recurrence. These therapeutics are available by prescription in the USA. RBX2660 (REBYOTA™) comprises a diverse consortium of live microbes derived from human stool and is administered via enema. On the other hand, SER-109 (VOWST™) is an orally administered spore-based medication. In this review, we discuss the potential of microbiota-based treatments for rCDI against the background of medico-legal challenges associated with classical FMT.

Key Messages

FMT has emerged as a highly effective cure for rCDI. Nonetheless, regulatory prerequisites and laborious preparation procedures impede its widespread use. The establishment of ready-to-use microbiota-based therapeutics in clinical practice is necessary. In the USA, the recent approval of the first two commercial medications, including a spore-based oral preparation, marks a significant step forward.

Retrospective subgroup analysis of fecal microbiota, live-jslm (REBYOTA®) administered by colonoscopy under enforcement discretion for the prevention of recurrent Clostridioides difficile infection

Background

Fecal microbiota, live-jslm (RBL; REBYOTA®), is the first Food and Drug Administration (FDA)-approved, single-dose, rectally administered, microbiota-based live biotherapeutic product for preventing Clostridioides difficile infection (CDI) recurrence. Alternative routes of administration are of clinical interest.

Objectives

Evaluate the safety and efficacy of RBL administration via colonoscopy.

Design

Retrospective analysis of electronic medical records of participants administered RBL via colonoscopy under FDA enforcement discretion.

Methods

The number of participants with treatment and/or procedure-emergent adverse events (TEAEs) was evaluated. Treatment success and sustained clinical response, defined as the absence of CDI recurrence within 8 weeks and 6 months, respectively, were evaluated.

Results

TEAEs were experienced by 75% (6/8) of participants; most were mild to moderate in severity, and none due to RBL or its administration. Most participants had treatment success (80%; 8/10); 75% (6/8) had sustained clinical response.

Conclusion

Real-world safety and efficacy of RBL administered via colonoscopy were consistent with clinical trials of rectally administered RBL.

Graphical abstract

Management of Clostridioides difficile infection: Diagnosis, Treatment, and Future Perspectives

Clostridioides difficile infection is the most common healthcare-associated infection in the United States, with potential life-threatening complications and significant impact in the costs of care. Antibiotic stewardship as well as discontinuation of chronic acid suppressive therapy are key for its prevention and treatment. Effective infection management requires appropriate interpretation of diagnostic tests, as well as the use of vancomycin and fidaxomicin as first-line treatment. Novel treatments as Bezlotoxumab, fecal microbiota transplant and live biotherapeutic products are proven effective in recurrent C. difficile infection and addresses dysbiosis.

A review of fecal microbiota, live-jslm for the prevention of recurrent Clostridioides difficile infection

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

To review the composition, preparation, proposed mechanism of action, safety, efficacy, and current place in therapy of Rebyota (fecal microbiota, live-jslm).

SUMMARY

As the first agent in a new class of drugs, live biotherapeutic products (LBPs), fecal microbiota, live-jslm offers another therapeutic approach for the prevention of recurrent Clostridioides difficile infection (rCDI). LBPs are given following antibiotic therapy for C. difficile to reintroduce certain bacteria present in the normal microbiome, as a means to reconstitute the microbiome of infected individuals. This review provides a summary of phase 2 and 3 clinical trials, product information, discussion of data limitations, and recommendations for place in therapy. High efficacy rates compared to placebo with sustained response up to 24 months after administration have been reported. The majority of adverse events identified were mild to moderate without significant safety signals.

CONCLUSION

Fecal microbiota, live-jslm has consistently been shown in randomized trials to be safe and effective in reducing rCDI. Its approval marks the culmination of decades of work to identify, characterize, and refine the intestinal microbiome to create pharmaceutical products.

Antibacterial activity of ibezapolstat against antimicrobial-resistant clinical strains of Clostridioides difficile

Antimicrobial resistance is emerging in clinical strains of Clostridioides difficile. Ibezapolstat (IBZ) is a DNA polymerase IIIC inhibitor that has completed phase II clinical trials. IBZ has potent in vitro activity against wild-type, susceptible strains but its effect on C. difficile strains with reduced susceptibility to metronidazole (MTZ), vancomycin (VAN), or fidaxomicin (FDX) has not been tested. The primary objective of this study was to test the antibacterial properties of IBZ against multidrug-resistant C. difficile strains. The in vitro activity, bactericidal, and time-kill activity of IBZ versus comparators were evaluated against 100 clinical strains of which 59 had reduced susceptibility to other C. difficile antibiotics. Morphologic changes against a multidrug resistance strain were visualized by light and scanning electron microscopy. The overall IBZ MIC50/90 values (µg/mL) for evaluated C. difficile strains were 4/8, compared with 2/4 for VAN, 0.5/1 for FDX, and 0.25/4 for MTZ. IBZ MIC50/90 values did not differ based on non-susceptibility to antibiotic class or number of classes to which strains were non-susceptible. IBZ bactericidal activity was similar to the minimum inhibitory concentration (MIC) and maintained in wild-type and non-susceptible strains. Time-kill assays against two laboratory wild-type and two clinical non-susceptible strains demonstrated sustained IBZ activity despite reduced killing by comparator antibiotics for IBZ and VAN non-susceptible strains. Microscopy visualized increased cell lengthening and cellular damage in multidrug-resistant strains exposed to IBZ sub-MIC concentrations. This study demonstrated the potent antibacterial activity of IBZ against a large collection of C. difficile strains including multidrug-resistant strains. This study highlights the therapeutic potential of IBZ against multidrug-resistant strains of C. difficile.

The microbiota-gut-brain axis in Huntington's disease: pathogenic mechanisms and therapeutic targets

Huntington's disease (HD) is a currently incurable neurogenerative disorder and is typically characterized by progressive movement disorder (including chorea), cognitive deficits (culminating in dementia), psychiatric abnormalities (the most common of which is depression), and peripheral symptoms (including gastrointestinal dysfunction). There are currently no approved disease-modifying therapies available for HD, with death usually occurring approximately 10-25 years after onset, but some therapies hold promising potential. HD subjects are often burdened by chronic diarrhea, constipation, esophageal and gastric inflammation, and a susceptibility to diabetes. Our understanding of the microbiota-gut-brain axis in HD is in its infancy and growing evidence from preclinical and clinical studies suggests a role of gut microbial population imbalance (gut dysbiosis) in HD pathophysiology. The gut and the brain can communicate through the enteric nervous system, immune system, vagus nerve, and microbiota-derived-metabolites including short-chain fatty acids, bile acids, and branched-chain amino acids. This review summarizes supporting evidence demonstrating the alterations in bacterial and fungal composition that may be associated with HD. We focus on mechanisms through which gut dysbiosis may compromise brain and gut health, thus triggering neuroinflammatory responses, and further highlight outcomes of attempts to modulate the gut microbiota as promising therapeutic strategies for HD. Ultimately, we discuss the dearth of data and the need for more longitudinal and translational studies in this nascent field. We suggest future directions to improve our understanding of the association between gut microbes and the pathogenesis of HD, and other 'brain and body disorders'.

AGA Clinical Practice Guideline on Fecal Microbiota-Based Therapies for Select Gastrointestinal Diseases

BACKGROUND & AIMS

Fecal microbiota-based therapies include conventional fecal microbiota transplant and US Food and Drug Administration-approved therapies, fecal microbiota live-jslm and fecal microbiota spores live-brpk. The American Gastroenterological Association (AGA) developed this guideline to provide recommendations on the use of fecal microbiota-based therapies in adults with recurrent Clostridioides difficile infection; severe to fulminant C difficile infection; inflammatory bowel diseases, including pouchitis; and irritable bowel syndrome.

METHODS

The guideline was developed using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) framework to prioritize clinical questions, identify patient-centered outcomes, and conduct an evidence synthesis. The guideline panel used the Evidence-to-Decision framework to develop recommendations for the use of fecal microbiota-based therapies in the specified gastrointestinal conditions and provided implementation considerations for clinical practice.

RESULTS

The guideline panel made 7 recommendations. In immunocompetent adults with recurrent C difficile infection, the AGA suggests select use of fecal microbiota-based therapies on completion of standard of care antibiotics to prevent recurrence. In mildly or moderately immunocompromised adults with recurrent C difficile infection, the AGA suggests select use of conventional fecal microbiota transplant. In severely immunocompromised adults, the AGA suggests against the use of any fecal microbiota-based therapies to prevent recurrent C difficile. In adults hospitalized with severe or fulminant C difficile not responding to standard of care antibiotics, the AGA suggests select use of conventional fecal microbiota transplant. The AGA suggests against the use of conventional fecal microbiota transplant as treatment for inflammatory bowel diseases or irritable bowel syndrome, except in the context of clinical trials.

CONCLUSIONS

Fecal microbiota-based therapies are effective therapy to prevent recurrent C difficile in select patients. Conventional fecal microbiota transplant is an adjuvant treatment for select adults hospitalized with severe or fulminant C difficile infection not responding to standard of care antibiotics. Fecal microbiota transplant cannot yet be recommended in other gastrointestinal conditions.

Clostridioides difficile infection: history, epidemiology, risk factors, prevention, clinical manifestations, treatment, and future options

SUMMARYClostridioides difficile infection (CDI) is one of the major issues in nosocomial infections. This bacterium is constantly evolving and poses complex challenges for clinicians, often encountered in real-life scenarios. In the face of CDI, we are increasingly equipped with new therapeutic strategies, such as monoclonal antibodies and live biotherapeutic products, which need to be thoroughly understood to fully harness their benefits. Moreover, interesting options are currently under study for the future, including bacteriophages, vaccines, and antibiotic inhibitors. Surveillance and prevention strategies continue to play a pivotal role in limiting the spread of the infection. In this review, we aim to provide the reader with a comprehensive overview of epidemiological aspects, predisposing factors, clinical manifestations, diagnostic tools, and current and future prophylactic and therapeutic options for C. difficile infection.

The Role of Probiotics in the Prevention of Clostridioides difficile Infection in Patients with Chronic Kidney Disease

In patients suffering from chronic kidney disease (CKD), substantial unfavourable alterations in the intestinal microbiota composition, i.e., dysbiosis, have been noted. The main causes of such dysbiosis among others are insufficient dietary fibre content in the diet, fluid restrictions, medications used, and physical activity limitation. One clinically important consequence of dysbiosis in CKD patients is high risk of Clostridioides difficile infection (CDI). In observational studies, it was found that CDI is more frequent in CKD patients than in the general population. This appears to be related to high hospitalization rate and more often antibiotic therapy use, leading up to the occurrence of dysbiosis. Therefore, the use of probiotics in CKD patients may avert changes in the intestinal microbiota, which is the major risk factor of CDI. The aim of this review paper is to summarize the actual knowledge concerning the use of probiotics in CDI prevention in CKD patients in the context of CDI prevention in the general population.

Advances in Therapeutic Strategies for the Management of Clostridioides difficile Infection

The infection caused by Clostridioides difficile represents one of the bacterial infections with the greatest increase in incidence among nosocomial infections in recent years. C. difficile is a Gram-positive bacterium able to produce toxins and spores. In some cases, infection results in severe diarrhoea and fulminant colitis, which cause prolonged hospitalisation and can be fatal, with repercussions also in terms of health economics. C. difficile is the most common cause of antibiotic-associated diarrhoea in the healthcare setting. The problem of bacterial forms that are increasingly resistant to common antibiotic treatments is also reflected in C. difficile infection (CDI). One of the causes of CDI is intestinal dysmicrobialism induced by prolonged antibiotic therapy. Moreover, in recent years, the emergence of increasingly virulent strains resistant to antibiotic treatment has made the picture even more complex. Evidence on preventive treatments to avoid recurrence is unclear. Current guidelines indicate the following antibiotics for the treatment of CDI: metronidazole, vancomycin, and fidaxomycin. This short narrative review provides an overview of CDI, antibiotic resistance, and emerging treatments.

Microbiota-gut-brain axis and its therapeutic applications in neurodegenerative diseases

The human gastrointestinal tract is populated with a diverse microbial community. The vast genetic and metabolic potential of the gut microbiome underpins its ubiquity in nearly every aspect of human biology, including health maintenance, development, aging, and disease. The advent of new sequencing technologies and culture-independent methods has allowed researchers to move beyond correlative studies toward mechanistic explorations to shed light on microbiome-host interactions. Evidence has unveiled the bidirectional communication between the gut microbiome and the central nervous system, referred to as the "microbiota-gut-brain axis". The microbiota-gut-brain axis represents an important regulator of glial functions, making it an actionable target to ameliorate the development and progression of neurodegenerative diseases. In this review, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases. As the gut microbiome provides essential cues to microglia, astrocytes, and oligodendrocytes, we examine the communications between gut microbiota and these glial cells during healthy states and neurodegenerative diseases. Subsequently, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases using a metabolite-centric approach, while also examining the role of gut microbiota-related neurotransmitters and gut hormones. Next, we examine the potential of targeting the intestinal barrier, blood-brain barrier, meninges, and peripheral immune system to counteract glial dysfunction in neurodegeneration. Finally, we conclude by assessing the pre-clinical and clinical evidence of probiotics, prebiotics, and fecal microbiota transplantation in neurodegenerative diseases. A thorough comprehension of the microbiota-gut-brain axis will foster the development of effective therapeutic interventions for the management of neurodegenerative diseases.

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.

Fecal microbiome composition and diversity of cryopreserved canine stool at different duration and storage conditions

Fresh-frozen stool banks intended for humans with gastrointestinal and metabolic disorders have been recently established and there are ongoing efforts to establish the first veterinary fresh-frozen stool bank. Fresh frozen stored feces provide an advantage of increased availability and accessibility to high-quality optimal donor fecal material. The stability of frozen canine feces regarding fecal microbiome composition and diversity has not been reported in dogs, providing the basis for this study. We hypothesized that fecal microbial composition and diversity of healthy dogs would remain stable when stored at -20°C and -80°C for up to 12 months compared to baseline samples evaluated before freezing. Stool samples were collected from 20 apparently healthy dogs, manually homogenized, cryopreserved in 20% glycerol and aliquoted, frozen in liquid nitrogen and stored at -20°C or -80°C for 3, 6, 9, and 12 months. At baseline and after period of storage, aliquots were thawed and treated with propidium monoazide before fecal DNA extraction. Following long-read 16S-rRNA amplicon sequencing, bacterial community composition and diversity were compared among treatment groups. We demonstrated that fresh-frozen canine stools collected from 20 apparently healthy dogs could be stored for up to 12 months at -80°C with minimal change in microbial community composition and diversity and that storage at -80°C is superior to storage at -20°C. We also found that differences between dogs had the largest effect on community composition and diversity. Relative abundances of certain bacterial taxa, including those known to be short-chain fatty acid producers, varied significantly with specific storage temperatures and duration. Further work is required to ascertain whether fecal donor material that differs in bacterial community composition and diversity across storage conditions and duration could lead to differences in clinical efficacy for specific clinical indications of fecal microbiota transplantation.

Radiation injury and gut microbiota-based treatment

The exposure to either medical sources or accidental radiation can cause varying degrees of radiation injury (RI). RI is a common disease involving multiple human body parts and organs, yet effective treatments are currently limited. Accumulating evidence suggests gut microbiota are closely associated with the development and prevention of various RI. This article summarizes 10 common types of RI and their possible mechanisms. It also highlights the changes and potential microbiota-based treatments for RI, including probiotics, metabolites, and microbiota transplantation. Additionally, a 5P-Framework is proposed to provide a comprehensive strategy for managing RI.

Multi-omics approaches to studying gastrointestinal microbiome in the context of precision medicine and machine learning

The human gastrointestinal (gut) microbiome plays a critical role in maintaining host health and has been increasingly recognized as an important factor in precision medicine. High-throughput sequencing technologies have revolutionized -omics data generation, facilitating the characterization of the human gut microbiome with exceptional resolution. The analysis of various -omics data, including metatranscriptomics, metagenomics, glycomics, and metabolomics, holds potential for personalized therapies by revealing information about functional genes, microbial composition, glycans, and metabolites. This multi-omics approach has not only provided insights into the role of the gut microbiome in various diseases but has also facilitated the identification of microbial biomarkers for diagnosis, prognosis, and treatment. Machine learning algorithms have emerged as powerful tools for extracting meaningful insights from complex datasets, and more recently have been applied to metagenomics data via efficiently identifying microbial signatures, predicting disease states, and determining potential therapeutic targets. Despite these rapid advancements, several challenges remain, such as key knowledge gaps, algorithm selection, and bioinformatics software parametrization. In this mini-review, our primary focus is metagenomics, while recognizing that other -omics can enhance our understanding of the functional diversity of organisms and how they interact with the host. We aim to explore the current intersection of multi-omics, precision medicine, and machine learning in advancing our understanding of the gut microbiome. A multidisciplinary approach holds promise for improving patient outcomes in the era of precision medicine, as we unravel the intricate interactions between the microbiome and human health.

Clostridioides Difficile: A Concise Review of Best Practices and Updates

Clostridioides difficile infection (CDI) is one of the most common and severe nosocomial infections worldwide. It can also affect healthy individuals in the community. The incidence of CDI has been on the rise globally for the past decade, necessitating a proactive approach to combat its spread; new strategies are being developed to enhance diagnostic accuracy and optimize treatment outcomes. Implementing the 2-step testing has increased diagnostic specificity, reducing the usage of CD-specific antibiotics with no concomitant increase in surgical complication rates. In 2021, the Infectious Diseases Society of America/Society for Healthcare Epidemiology of America (IDSA/SHEA) shifted its preference for initial treatment to fidaxomicin over vancomycin and metronidazole due to its lower recurrence rate. It also prioritized fidaxomicin for the treatment of recurrent CDI. There are new developments on the frontiers of fecal microbiota therapies, with RBX2660 and SER-109 approved recently by the FDA for prevention, with other microbiome-based therapies in various development and clinical trials. This review offers providers an updated and practical guide for CDI management.

Fecal Microbiota Transplantation as Emerging Treatment in European Countries 2.0

Clostridioides difficile infection (CDI) is one of the most common healthcare-associated infections and one of the leading causes of morbidity and mortality in hospitalized patients in the world. Although several antibiotics effectively treat CDI, some individuals may not respond to these drugs and may be cured by transplanting stool from healthy donors. FMT has demonstrated extraordinary cure rates for the cure of CDI recurrences.Moreover, FMT has also been investigated in other disorders associated with the alteration of gut microbiota, such as inflammatory bowel disease (IBD), where the alterations of the gut microbiota ecology have been theorized to play a causative role. Although FMT is currently not recommended to cure IBD patients in clinical practice, several studies have been recently carried out with the ultimate goal to search new therapeutic options to patients.This review summarizes data on the use of FMT for the treatment of both CDI and IBD, with a special attention to highlight studies conducted in European countries.

European Practice for CDI Treatment

Clostridioides difficile infection (CDI) remains a significant cause of morbidity and mortality worldwide. Historically, two antibiotics (metronidazole and vancomycin) and a recent third (fidaxomicin) have been used for CDI treatment; convincing data are now available showing that metronidazole is the least efficacious agent. The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) management guidance for CDI were updated in 2021. This guidance document outlines the treatment options for a variety of CDI clinical scenarios and for non-antimicrobial management (e.g., faecal microbiota transplantation, FMT). One of the main changes is that metronidazole is no longer recommended as first-line CDI treatment. Rather, fidaxomicin is preferred on the basis of reduced recurrence rates with vancomycin as an acceptable alternative. Recommended options for recurrent CDI now include bezlotoxumab as well as FMT.A 2017 survey of 20 European countries highlighted variation internationally in CDI management strategies. A variety of restrictions were in place in 65% countries prior to use of new anti-CDI treatments, including committee/infection specialist approval or economic review/restrictions. This survey was repeated in November 2022 to assess the current landscape of CDI management practices in Europe. Of 64 respondents from 17 countries, national CDI guidelines existed in 14 countries, and 11 have already/plan to incorporate the ESCMID 2021 CDI guidance, though implementation has not been surveyed in 6. Vancomycin is the most commonly used first-line agent for the treatment of CDI (n = 42, 66%), followed by fidaxomicin (n = 30, 47%). Six (9%) respondents use metronidazole as first-line agent for CDI treatment, whereas 22 (34%) only in selected low-risk patient groups. Fidaxomicin is more likely to be used in high-risk patient groups. Availability of anti-CDI therapy influenced prescribing in six respondents (9%). Approval pre-prescription was required before vancomycin (n = 3, 5%), fidaxomicin (n = 10, 6%), bezlotoxumab (n = 11, 17%) and FMT (n = 10, 6%). Implementation of CDI guidelines is rarely audited.Novel anti-CDI agents are being evaluated; it is not yet clear what will be the roles of these agents. The treatment of recurrent CDI is particularly troublesome, and several different live biotherapeutics are being developed, in addition to FMT.

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.

Efficacy and Health-Related Quality of Life Impact of Fecal Microbiota, Live-jslm: A Post Hoc Analysis of PUNCH CD3 Patients at First Recurrence of Clostridioides difficile Infection

INTRODUCTION

Clostridioides difficile infection (CDI) causes symptoms of varying severity and negatively impacts patients' health-related quality of life (HRQL). Despite antibiotic treatment, recurrence of CDI (rCDI) is common and imposes clinical and economic burdens on patients. Fecal microbiota, live-jslm (REBYOTA [RBL]) is newly approved in the USA for prevention of rCDI following antibiotic treatments. We analyzed efficacy and HRQL impact of RBL vs. placebo in patients at first rCDI using data from the phase 3 randomized, double-blind placebo-controlled clinical trial, PUNCH CD3.

METHODS

This post hoc analysis included patients at first rCDI fromPUNCH CD3. Treatment success (i.e., absence of diarrhea within 8 weeks post-treatment) was analyzed adjusting for baseline patient characteristics. HRQL was measured using the Clostridioides difficile Quality of Life Survey (Cdiff32); absolute scores and change from baseline in total and domain (physical, mental, and social) scores were summarized and compared between arms. Analyses were conducted for the trial's blinded phase only.

RESULTS

Among 86 eligible patients (32.8% of the overall trial population, RBL 53 [61.6%], placebo 33 [38.4%]), RBL-treated patients had significantly lower odds of recurrence (i.e., greater probability of treatment success) at week 8 vs. placebo (odds ratio 0.35 [95% confidence interval 0.13, 0.98]). Probability of treatment success at week 8 was 81% for RBL and 60% for placebo, representing 21% absolute and 35% relative increases for RBL (crude proportions 79.2% vs. 60.6%; relative risk 0.53, p = 0.06). Additionally, RBL was associated with significantly higher Cdiff32 total (change score difference 13.5 [standard deviation 5.7], p < 0.05) and mental domain (16.2 [6.0], p < 0.01) scores vs. placebo from baseline to week 8.

CONCLUSION

Compared to placebo, RBL demonstrated a significantly higher treatment success in preventing further rCDI and enhanced HRQL among patients at first recurrence, establishing RBL as an effective treatment to prevent further recurrences in these patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT03244644.

pH-dependent pressure-sensitive colonic capsules for the delivery of aqueous bacterial suspensions

Microbiome-based therapies hold great promise for treating various diseases, but the efficient delivery of live bacteria to the colon remains a challenge. Furthermore, current oral formulations, such as lyophilized bacterial capsules or tablets, are produced using processes that can decrease bacterial viability. Consequently, high dosages are required to achieve efficacy. Herein, we report the design of pressure-sensitive colonic capsules for the encapsulation and delivery of aqueous suspensions of live bacteria. The capsules consisted of 2 functional thin-films (hydrophobic and enteric) of ethyl cellulose and Eudragit S100 dip-coated onto hydroxypropyl methylcellulose molds. The capsules could be loaded with aqueous media and provide protection against acidic fluids and, to some extent, oxygen diffusion, suggesting their potential suitability for delivering anaerobic bacterial strains. Disintegration and mechanical studies indicated that the capsules could withstand transit through the stomach and upper/proximal small intestinal segments and rupture in the ileum/colon. In vitro studies showed that bacterial cells (anaerobic and aerobic commensals) remained highly viable (74-98%) after encapsulation and exposure to the simulated GI tract conditions. In vivo studies with a beagle dog model revealed that 67% of the capsules opened after 3.5 h, indicating content release in the distal gastrointestinal tract. These data demonstrate that live aqueous bacterial suspensions comprised of both aerobic and anaerobic commensals can be encapsulated and in the future might be efficiently delivered to the distal gastrointestinal tract, suggesting the practical applications of these capsules in microbiome-based therapies.

Infectious Inequity: How the Gut Microbiome and Social Determinants of Health May Contribute to Clostridioides difficile Infection Among Racial and Ethnic Minorities

Infectious diseases are a leading contributor to death in the United States, and racial differences in clinical outcomes have been increasingly reported. Clostridioides difficile infection (CDI) is a growing public health concern, as it causes nearly half a million infections per year and considerable excess hospital costs. Concurrent with other infectious diseases, recent literature denotes racial disparities in CDI incidence rates, mortality, and associated morbidity. Of note, investigations into CDI and causative factors suggest that inequities in health-related social needs and other social determinants of health (SDoH) may cause disruption to the gut microbiome, thereby contributing to the observed deleterious outcomes in racially and ethnically minoritized individuals. Despite these discoveries, there is limited literature that provides context for the recognized racial disparities in CDI, particularly the influence of structural and systemic barriers. Here, we synthesize the available literature describing racial inequities in CDI outcomes and discuss the interrelationship of SDoH on microbiome dysregulation. Finally, we provide actionable considerations for infectious diseases professionals to aid in narrowing CDI equity gaps.

Advancements in Novel Live Biotherapeutic Products for Clostridioides difficile Infection Prevention

The profound impact of the human microbiome on health and disease has captivated the interest of clinical and scientific communities. The human body hosts a vast array of microorganisms collectively forming the human microbiome, which significantly influences various physiological processes and profoundly shapes overall well-being. Notably, the gut stands out as an exceptional reservoir, harboring the most significant concentration of microorganisms, akin to an organ in itself. The gut microbiome's composition and function are influenced by genetics, environment, age, underlying conditions, and antibiotic usage, leading to dysbiosis and pathogenesis, such as Clostridioides difficile infection (CDI). Conventional CDI treatment, involving antibiotics like oral vancomycin and fidaxomicin, fails to address dysbiosis and may further disrupt gut microbial communities. Consequently, emerging therapeutic strategies are focused on targeting dysbiosis and restoring gut microbiota to advance CDI therapeutics. Fecal microbiota transplantation (FMT) has demonstrated remarkable efficacy in treating recurrent CDI by transferring processed stool from a healthy donor to a recipient, restoring gut dysbiosis and enhancing bacterial diversity. Moreover, 2 newer Food and Drug Administration (FDA)-approved live biotherapeutic products (LBP), namely, Fecal Microbiota Live-JSLM and Fecal Microbiota Spores Live-BRPK, have shown promise in preventing CDI recurrence. This review explores the role of the gut microbiota in preventing and treating CDI, with an emphasis on gut-based interventions like FMT and fecal microbiota-based products that hold potential for gut restoration and prevention of CDI recurrence. Understanding the microbiome's impact on CDI prevention and treatment offers valuable insights for advancing future CDI therapeutics.

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.

The Next Generation Fecal Microbiota Transplantation: To Transplant Bacteria or Virome

Fecal microbiota transplantation (FMT) has emerged as a promising therapeutic approach for dysbiosis-related diseases. However, the clinical practice of crude fecal transplants presents limitations in terms of acceptability and reproductivity. Consequently, two alternative solutions to FMT are developed: transplanting bacteria communities or virome. Advanced methods for transplanting bacteria mainly include washed microbiota transplantation and bacteria spores treatment. Transplanting the virome is also explored, with the development of fecal virome transplantation, which involves filtering the virome from feces. These approaches provide more palatable options for patients and healthcare providers while minimizing research heterogeneity. In general, the evolution of the next generation of FMT in global trends is fecal microbiota components transplantation which mainly focuses on transplanting bacteria or virome.

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.

Drug and gut microbe relationships: Moving beyond antibiotics

Our understanding of drug-microbe relationships has evolved from viewing microbes as mere drug producers to a dynamic, modifiable system where they can serve as drugs or targets of precision pharmacology. This review highlights recent findings on the gut microbiome, particularly focusing on four aspects of research: (i) drugs for bugs, covering recent strategies for targeting gut pathogens; (ii) bugs as drugs, including probiotics; (iii) drugs from bugs, including postbiotics; and (iv) bugs and drugs, discussing additional types of drug-microbe interactions. This review provides a perspective on future translational research, including efficient companion diagnostics in pharmaceutical interventions.

[Microbiome: from pathophysiology to clinical application?]

The "microbiome" or the intestinal microbiota is currently in the focus of scientific interest. The number of publications on the topic of the microbiome is increasing every year. In particular, the role of the microbiome in the pathophysiology of various diseases has been studied. Currently it is impossible to have an overview on all new developments with over 25.000 publication in the field per year. However, some key news stand out from this large number of publications. The first microbiota compounds for the therapy of Clostridioides difficile colitis were approved by the FDA last year or are about to be approved. This means that, for the first time, standardized microbiome products are available in addition to fecal microbiota transplantation (FMT) and are finding their way into everyday clinical practice.

Recurrent Clostridioides difficile Infection: Current Clinical Management and Microbiome-Based Therapies

Clostridioides difficile is one of the most important causes of healthcare-associated diarrhea. The high incidence and recurrence rates of C. difficile infection, as well as its associated morbidity and mortality, are great concerns. The most common complication of C. difficile infection is recurrence, with rates of 20-30% after a primary infection and 60% after three or more episodes. Medical management of recurrent C. difficile infection involves a choice of therapy that is different from the antibiotic used in the primary episode. Patients with recurrent C. difficile infection also benefit from fecal microbiota transplantation or standardized microbiome restoration therapies (approved or experimental) to restore eubiosis. In contrast to antibiotics, microbiome restoration therapies restore a normal gut flora and eliminate C. difficile colonization and infection. Fecal microbiota transplantation in recurrent C. difficile infection has demonstrated higher success rates than vancomycin, fidaxomicin, or placebo. Fecal microbiota transplantation has traditionally been considered safe, with the most common adverse reactions being abdominal discomfort, and diarrhea, and rare serious adverse events. Significant heterogeneity and a lack of standardization regarding the process of preparation, and administration of fecal microbiota transplantation remain a major pitfall. Standardized microbiome-based therapies provide a promising alternative. In the ECOSPOR III trial of SER-109, an oral formulation of bacterial spores, a significant reduction in the recurrence rate (12%) was observed compared with placebo (40%). In the phase III PUNCH CD3 trial, RBX2660 also demonstrated high efficacy rates of 70.6% versus 57.5%. Both these agents are now US Food and Drug Administration approved for recurrent C. difficile infection. Other standardized microbiome-based therapies currently in the pipeline are VE303, RBX7455, and MET-2. Antibiotic neutralization strategies, vaccines, passive monoclonal antibodies, and drug repurposing are other therapeutic strategies being explored to treat C. difficile infection.

Therapeutic Approach Targeting Gut Microbiome in Gastrointestinal Infectious Diseases

While emerging evidence highlights the significance of gut microbiome in gastrointestinal infectious diseases, treatments like Fecal Microbiota Transplantation (FMT) and probiotics are gaining popularity, especially for diarrhea patients. However, the specific role of the gut microbiome in different gastrointestinal infectious diseases remains uncertain. There is no consensus on whether gut modulation therapy is universally effective for all such infections. In this comprehensive review, we examine recent developments of the gut microbiome's involvement in several gastrointestinal infectious diseases, including infection of Helicobacter pylori, Clostridium difficile, Vibrio cholerae, enteric viruses, Salmonella enterica serovar Typhimurium, Pseudomonas aeruginosa Staphylococcus aureus, Candida albicans, and Giardia duodenalis. We have also incorporated information about fungi and engineered bacteria in gastrointestinal infectious diseases, aiming for a more comprehensive overview of the role of the gut microbiome. This review will provide insights into the pathogenic mechanisms of the gut microbiome while exploring the microbiome's potential in the prevention, diagnosis, prediction, and treatment of gastrointestinal infections.

Identification of Micrococcin P2-Derivatives as Antibiotic Candidates against Two Gram-Positive Pathogens

Thiopeptides exhibit potent antimicrobial activity against Gram-positive pathogens by inhibiting bacterial protein synthesis. Micrococcins are among the structurally simpler thiopeptides, but they have not been exploited in detail. This research involved a computational simulation of micrococcin P2 (MP2) docking in parallel with the structure-activity relationship (SAR) studied. The incorporation of particular nitrogen heterocycles in the side chain of MP2 enhances the antimicrobial activity. Micrococcin analogues 6c and 6d thus proved to be more effective against impetigo and C. difficile infection (CDI), respectively, as compared to current first-line treatments. Compound 6c also showed a shorter treatment period than that of a first-line treatment for impetigo. This may be attributed to its ability to downregulate pro-inflammatory cytokines. Compound 6d had no observed recurrence for C. difficile and exerted a minimal impact on the beneficial gut microbiome. Their pharmacokinetic properties and low toxicity profile make these compounds ideal candidates for the treatment of impetigo and CDI and validate their involvement in preclinical development.

Strategies for applying probiotics in the antibiotic management of Clostridioides difficile infection

The vital role of probiotics in the food field has been widely recognized, and at the same time, probiotics are gradually exhibiting surprising effects in the field of nutraceuticals, especially in regulating gut inflammation and the nutritional environment. As a dietary supplement in clinical nutrition, the coadministration of probiotics with antibiotics model has been applied to prevent intestinal infections caused by Clostridioides difficile. However, the mechanism behind this "bacteria-drug combination" model remains unclear. In particular, the selection of specific probiotic strains, the order of probiotics or antibiotics, and the time interval of coadministration are key issues that need to be further explored and clarified. Here, we focus on the issues mentioned above and give reasonable opinions, mainly including: (1) probiotics are safer and more effective when they intervene after antibiotics have been used; (2) the choice of the time interval between coadministration should be based on the metabolism of antibiotics in the host, differences in probiotic strains, the baseline ecological environment of the host's intestine, and the host immune level; in addition, the selection of the coadministration regime should also take into account factors such as the antibiotic sensitivity of probiotics and dosage of probiotics; and (3) by encapsulating probiotics, combining probiotics with prebiotics, and developing next-generation probiotics (NGPs) and postbiotic formulations, we can provide a more reasonable reference for this type of "bacteria-drug combination" model, and also provide targeted guidance for the application of probiotic dietary supplements in the antibiotic management of C. difficile infection.

Microbiotoxicity: antibiotic usage and its unintended harm to the microbiome

PURPOSE OF REVIEW

Antibiotic use is associated with development of antimicrobial resistance and dysregulation of the microbiome (the overall host microbial community). These changes have in turn been associated with downstream adverse health outcomes. This review analyses recent important publications in a rapidly evolving field, contextualizing the available evidence to assist clinicians weighing the potential risks of antibiotics on a patient's microbiome.

RECENT FINDING

Although the majority of microbiome research is observational, we highlight recent interventional studies probing the associations between antibiotic use, microbiome disruption, and ill-health. These studies include germ-free mouse models, antibiotic challenge in healthy human volunteers, and a phase III study of the world's first approved microbiome-based medicine.

SUMMARY

The growing body of relevant clinical and experimental evidence for antibiotic-mediated microbiome perturbation is concerning, although further causal evidence is required. Within the limits of this evidence, we propose the novel term 'microbiotoxicity' to describe the unintended harms of antibiotics on a patient's microbiome. We suggest a framework for prescribers to weigh microbiotoxic effects against the intended benefits of antibiotic use.

Synthetic microbial consortia for the treatment of Clostridioides difficile infection in mice model

Clostridioides difficile infection (CDI) as of recent has become a great concern to the impact on human health due to its high hazardous risk and rate of recurrence. Live bacterial therapeutics is a promising method to treat or prevent CDI. Here, a synthetic microbial consortia (SMC) B10 was constructed using probiotic strains with antibacterial and anti-quorum sensing activities, and the therapeutic effect of SMC B10 against C. difficile infection was evaluated in vitro. Compared to the model group, the treatment of SMC B10 significantly increased the survival rate. The clinical signs of mice were significantly ameliorated, especially the cecum injury, while the secretion of pro-inflammatory associated cytokines such as IL-1α, IL-6, IL-17A and TNF-α was reduced, the expression of TLR4 was inhibited, which alleviated the inflammatory response, and the expression of the tight junction protein Claudin-1 was increased, ultimately promoting the recovery of host health. The treatment of B10 restored gut microbiota dysbiosis and led to a healthy intestinal microbiota structure, significantly improved alpha diversity, suppressing potentially harmful bacteria and restoring other core bacterial species. In conclusion, SMC B10 can effectively treat CDI through modulate gut microbiota and attenuate the inflammatory response.

Washed microbiota transplantation for Clostridioides difficile infection: A national multicenter real-world study

OBJECTIVES

Fecal microbiota transplantation (FMT) has been recommended for the treatment of recurrent Clostridioides difficile infection (CDI). We aimed to evaluate the therapeutic efficacy and safety of washed microbiota transplantation (WMT), a new method of FMT, for CDI across various medical settings.

METHODS

This multicenter real-world cohort study included CDI patients undergoing WMT. The primary outcome was the clinical cure rate of CDI within 8 weeks after WMT. Secondary outcomes included the CDI recurrence rate and reduction in total abdominal symptom score (TASS) during the follow-up period. Adverse events related to WMT were recorded.

RESULTS

Altogether 90.7% (49/54) of CDI patients achieved clinical cure after treated with WMT. The cure rate was 83.3% for cases with severe and complicated CDI (ScCDI) (n = 30) and 100% for non-ScCDI cases (n = 24) (P = 0.059). No difference was observed in the clinical cure rate between patients with first and recurrent CDI (91.9% vs 88.2%, P = 0.645). One week post-WMT, TASS showed a remarkable decrease compared to that at baseline (P < 0.001). Totally, 8.2% (4/49) of patients suffered CDI recurrence during the follow-up period. A WHO performance score of 4, age ≥65 years, higher TASS score, and higher Charlson comorbidity index score were potential risk factors for efficacy (P = 0.018, 0.03, 0.01, 0.034, respectively). Four (3.8%) transient adverse events related to WMT were observed.

CONCLUSIONS

This study emphasizes the attractive value of WMT for CDI. Early WMT may be recommended for CDI, especially for those in serious condition or with complex comorbidities.

TRIAL REGISTRATION

ClinicalTrials.gov, no. NCT03895593 (registered on 27 March 2019).