A Novel Microbiome Therapeutic Increases Gut Microbial Diversity and Prevents Recurrent Clostridium difficile Infection

Clinical translation of microbiome research

The landscape of clinical microbiome research has dramatically evolved over the past decade. By leveraging in vivo and in vitro experimentation, multiomic approaches and computational biology, we have uncovered mechanisms of action and microbial metrics of association and identified effective ways to modify the microbiome in many diseases and treatment modalities. This Review explores recent advances in the clinical application of microbiome research over the past 5 years, while acknowledging existing barriers and highlighting opportunities. We focus on the translation of microbiome research into clinical practice, spearheaded by Food and Drug Administration (FDA)-approved microbiome therapies for recurrent Clostridioides difficile infections and the emerging fields of microbiome-based diagnostics and therapeutics. We highlight key examples of studies demonstrating how microbiome mechanisms, metrics and modifiers can advance clinical practice. We also discuss forward-looking perspectives on key challenges and opportunities toward integrating microbiome data into routine clinical practice, precision medicine and personalized healthcare and nutrition.

From big data and experimental models to clinical trials: Iterative strategies in microbiome research

Microbiome research has expanded significantly in the last two decades, yet translating findings into clinical applications remains challenging. This perspective discusses the persistent issue of correlational studies in microbiome research and proposes an iterative method leveraging in silico, in vitro, ex vivo, and in vivo studies toward successful preclinical and clinical trials. The evolution of research methodologies, including the shift from small cohort studies to large-scale, multi-cohort, and even "meta-cohort" analyses, has been facilitated by advancements in sequencing technologies, providing researchers with tools to examine multiple health phenotypes within a single study. The integration of multi-omics approaches-such as metagenomics, metatranscriptomics, metaproteomics, and metabolomics-provides a comprehensive understanding of host-microbe interactions and serves as a robust hypothesis generator for downstream in vitro and in vivo research. These hypotheses must then be rigorously tested, first with proof-of-concept experiments to clarify the causative effects of the microbiota, and then with the goal of deep mechanistic understanding. Only following these two phases can preclinical studies be conducted with the goal of translation into the clinic. We highlight the importance of combining traditional microbiological techniques with big-data approaches, underscoring the necessity of iterative experiments in diverse model systems to enhance the translational potential of microbiome research.

Validation methods for encapsulated faecal microbiota transplantation: a scoping review

Faecal microbiota transplantation (FMT) is increasingly used for diseases associated with a disrupted intestinal microbiome, mainly Clostridioides difficile infection. Encapsulated FMT is a patient-friendly application method that improves accessibility and convenience. Capsule processing may be standardised, but validation protocols are warranted. This review aimed to describe published validation methods for encapsulated FMT. Original studies reporting using encapsulated faecal formulations were included, regardless of indication. Studies were excluded if they did not address processing and validation or used non-donor-derived content. We conducted a comprehensive scoping review, implementing a systematic search strategy in PubMed, Embase and Web of Science. Processing data and validation methods were registered during full-text analysis and combined to create an overview of approaches for assessing quality in encapsulated FMT processing. The searches identified 324 unique studies, of which 44 were included for data extraction and analysis. We identified eight validation covariables: donor selection, pre-processing, preservation, oxygen-sparing processing, microbial count, viability, engraftment and clinical effect outcomes, from which we constructed a model for quality assessment of encapsulated FMT that exhaustively categorised processing details and validation measures. Our model comprised three domains: (1) Processing (donor selection and processing protocol), (2) Content analysis (microbiota measures and dose measures) and (3) Clinical effect (engraftment and clinical outcomes). No studies presented a reproducible capsule protocol; their validation strategies were sparse and divergent. The validation of FMT capsules is heterogeneous, and processing requires relevant standardisation protocols, mainly focusing on capsule content. Future studies should report validation covariables to enable accurate comparative assessments of clinical effects.

Gut-Heart Axis: Microbiome Involvement in Restrictive Cardiomyopathies

An intriguing aspect of restrictive cardiomyopathies (RCM) is the microbiome role in the natural history of the disease. These cardiomyopathies are often difficult to diagnose and so result in significant morbidity and mortality. The human microbiome, composed of billions of microorganisms, influences various physiological and pathological processes, including cardiovascular health. Studies have shown that gut dysbiosis, an imbalance in the composition of intestinal bacteria, can contribute to systemic inflammation, a key factor in many cardiovascular conditions. An increase in gut permeability, frequently caused by dysbiosis, allows bacterial endotoxins to enter the bloodstream, activating inflammatory pathways that exacerbate cardiac dysfunction. Recent reports highlight the potential role of microbiome in amyloidogenesis, as certain bacteria produce proteins that accelerate the formation of amyloid fibrils. Concurrently, advancements in amyloidosis treatments have sparked renewed hopes, marking a promising era for managing these kinds of diseases. These findings suggest that the gut-heart axis may be a potential factor in the development and progression of cardiovascular disease like RCM, opening new paths for therapeutic intervention. The aim of this review is to provide a detailed overview of the gut-heart axis, focusing on RCM.

Multi-omic profiling a defined bacterial consortium for treatment of recurrent Clostridioides difficile infection

Donor-derived fecal microbiota treatments are efficacious in preventing recurrent Clostridioides difficile infection (rCDI), but they have inherently variable quality attributes, are difficult to scale and harbor the risk of pathogen transfer. In contrast, VE303 is a defined consortium of eight purified, clonal bacterial strains developed for prevention of rCDI. In the phase 2 CONSORTIUM study, high-dose VE303 was well tolerated and reduced the odds of rCDI by more than 80% compared to placebo. VE303 organisms robustly colonized the gut in the high-dose group and were among the top taxa associated with non-recurrence. Multi-omic modeling identified antibiotic history, baseline stool metabolites and serum cytokines as predictors of both on-study CDI recurrence and VE303 colonization. VE303 potentiated early recovery of the host microbiome and metabolites with increases in short-chain fatty acids, secondary bile acids and bile salt hydrolase genes after antibiotic treatment for CDI, which is considered important to prevent CDI recurrences. These results support the idea that VE303 promotes efficacy in rCDI through multiple mechanisms.

Supplementation of Parachlorella sp. in feed promote the gut microbiome colonization and fecal IgA response of broiler in both early and late period

This study evaluated the effects of Parachlorella sp. KSN1 (PA) supplementation on the gut microbiota and intestinal immunity of broilers of different ages. A total of 180 Ross 308 broiler chicks were weighed and divided into early (1 to 10 days post hatch) and late (11 to 28 days post hatch) periods, with six replicates of 10 chicks per cage assigned to two dietary groups. The experimental diets included a corn-soybean meal-based control diet and a treatment diet supplemented with 0.5% PA, replacing corn or corn starch, and fed ad libitum for the assigned experimental period. On days 10 and 28, two broilers from each of the six replicate cages, with 7 broilers per cage in each group, were selected and euthanized, and cecal feces and intestinal tissue samples were collected. PA supplementation did not significantly affect broilers growth performance during both the early and the late periods. However, PA supplementation altered the cecal microbiome, with Clostridiaceae and Clostridium exhibiting prominent and consistent changes. In terms of intestinal immunity, PA supplementation significantly increased the number of CD3+ and CD4+ T cells when administered only during the early period. Cecal IgA levels were significantly increased by PA supplementation during both the early and late periods. A significant positive correlation was observed between IgA, Clostridiaceae and Clostridium during the early and late periods. Gene expression analysis identified 40 upregulated genes, including polymeric immunoglobulin receptor (pIgR), and 142 downregulated genes, including marginal zone B and B1 cell specific protein and immunoglobulin lambda-like polypeptide 1 that were associated with the IgA response in PA-treated broilers during the early period. This study demonstrated that PA supplementation promotes gut microbial colonization and intestinal immunity development during the early age of broilers. These findings suggest that the early growth period of broilers is the optimal time for dietary immunomodulation to promote gut health in broilers.

Factors for Treatment Failure After Fecal Microbiota Transplantation in Clostridioides difficile Infection

Recently, fecal microbiota transplantation (FMT) has been introduced as an effective treatment option for Clostridioides difficile infection (CDI). However, the risk factors associated with FMT treatment failure have not been well demonstrated. Therefore, we aimed to investigate the risk factors of treatment failure or recurrence after FMT for CDI. This retrospective study included 124 patients with CDI who underwent FMT at Inha University Hospital between November 2017 and August 2021 and were followed up for 8 weeks after FMT for symptoms of CDI. FMT failure was defined as diarrhea recurrence or a positive stool test. We assessed the risk factors for treatment failure, including comorbidities, antibiotic use pre- and post-FMT, and the number of CDI episodes before FMT. Ninety-three patients (75%) experienced symptom improvement <7 days after FMT, while treatment failure occurred in 40 patients (32.3%). Multivariate analysis revealed that males had a lower symptom improvement rate <7 days after FMT (p = 0.049). Patients using antibiotics after FMT showed a higher rate of recurrence or treatment failure in <8 weeks (p = 0.032). Patients requiring antibiotics after FMT should be considered at higher risk of treatment failure. Careful antibiotic stewardship, particularly minimizing non-essential antibiotic use before and after FMT, may significantly enhance treatment outcomes. Further large-scale prospective studies are warranted to confirm these findings and develop targeted antibiotic management protocols for improving the efficacy of FMT in CDI treatment.

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.

Post-infectious ibs following Clostridioides difficile infection; role of microbiota and implications for treatment

Up to 25% of patients recovering from antibiotic-treated Clostridioides difficile infection (CDI) develop functional symptoms reminiscent of Post-Infectious Irritable Bowel Syndrome (PI-IBS). For patients with persistent symptoms following infection, a clinical dilemma arises as to whether to provide additional antibiotic treatment or to adopt a conservative symptom-based approach. Here, we review the literature on CDI-related PI-IBS and compare the findings with PI-IBS. We review proposed mechanisms, including the role of C. difficile toxins and the microbiota, and discuss implications for therapy. We suggest that gut dysfunction post-CDI may be initiated by toxin-induced damage to enteroglial cells and that a dysbiotic gut microbitota maintains the clinical phenotype over time, prompting consideration of microbiota-directed therapies. While Fecal Microbial Transplant (FMT) is currently reserved for recurrent CDI (rCDI), we propose that microbiota-directed therapies may have a role in primary CDI in order to avoid or mitigate futher antibiotic treatment that further disrupts the microbiota and thus prevent PI-IBS. We discuss novel microbial transfer therapies and as they emerge, we recommend clinical trials to determine whether microbial transfer therapy of the primary infection prevents both rCDI and CDI-related PI- IBS.

Gut microbiota: the indispensable player in neurodegenerative diseases

As one of the most urgent social and health problems in the world, neurodegenerative diseases have always been of interest to researchers. However, the pathological mechanisms and therapeutic approaches are not achieved. In addition to the established roles of oxidative stress, inflammation and immune response, changes of gut microbiota are also closely related to the pathogenesis of neurodegenerative diseases. Gut microbiota is the central player of the gut-brain axis, the dynamic bidirectional communication pathway between gut microbiota and central nervous system, and emerging insights have confirmed its indispensability in the development of neurodegenerative diseases. In this review, we discuss the complex relationship between gut microbiota and the central nervous system from the perspective of the gut-brain axis; review the mechanism of microbiota for the modulation different neurodegenerative diseases and discuss how different dietary patterns affect neurodegenerative diseases via gut microbiota; and prospect the employment of gut microbiota in the therapeutic approach to those diseases. © 2024 Society of Chemical Industry.

Microbiome and Microbial Pure Culture Study Reveal Commensal Microorganisms Alleviate Salmonella enterica Serovar Pullorum Infection in Chickens

Pullorum disease, an intestinal disease in chickens caused by Salmonella enterica serovar pullorum (S. Pullorum), is a significant threat to the poultry industry and results in substantial economic losses. The bacteria's transmission, both vertical and horizontal, makes it difficult to completely eliminate it. Control strategies for pullorum disease primarily involve stringent eradication programs that cull infected birds and employ antibiotics for treatment. However, eradication programs are costly, and antibiotic use is restricted. Therefore, developing alternative control strategies is essential. Increasingly, studies are focusing on modulating the gut microbiota to control intestinal diseases. Modulating the chicken gut microbiota may offer a novel strategy for preventing and controlling pullorum disease in poultry. However, the impact of S. Pullorum on the chicken gut microbiota has not been well established, prompting our exploration of the relationship between S. Pullorum and the chicken gut microbiota in this study. In this study, we initially analyzed the dynamic distribution of the gut microbiota in chickens infected with S. Pullorum. Alpha diversity analysis revealed a decrease in observed OTUs and the Shannon diversity index in the infected group, suggesting a reduction in the richness of the chicken gut microbiota due to S. Pullorum infection. Principal coordinate analysis (PCoA) showed distinct clusters between the gut microbiota of infected and uninfected groups, indicating S. Pullorum infection changed the chicken gut microbiota structure. Specifically, S. Pullorum infection enriched the relative abundance of the genera Escherichia-Shigella (65% in infected vs. 40.6% in uninfected groups) and Enterococcus (10.8% vs. 3.7%) while reducing the abundance of Lactobacillus (9.9% vs. 32%) in the chicken microbiota. Additionally, based on the observed changes in the chicken gut microbiota, we isolated microorganisms, including Bifidobacterium pseudolongum, Streptococcus equi and Lacticaseibacillus paracasei (L. paracasei), which were decreased by S. Pullorum infection. Notably, the L. paracasei Lp02 strain was found to effectively inhibit S. Pullorum proliferation in vitro and alleviate its infection in vivo. We found that S. Pullorum infection reduced the richness of the chicken gut microbiota and enriched the relative abundance of the genera Escherichia-Shigella and Enterococcus while decreasing the abundance of the anaerobic genus Lactobacillus. Furthermore, microbiota analysis enabled the isolation of several antimicrobial microorganisms from healthy chicken feces, with a L. paracasei strain notably inhibiting S. Pullorum proliferation in vitro and alleviating its infection in vivo. Overall, this research enhances our understanding of the interaction between gut microbiota and pathogen infection, as well as offers new perspectives and strategies for modulating the chicken gut microbiota to control pullorum disease.

Fighting against Clostridioides difficile infection: Current medications

Clostridioides difficile (formerly Clostridium difficile) has been regarded as an 'urgent threat' and a significant global health problem, as life-threatening diarrhoea and refractory recurrence are common in patients with C. difficile infection (CDI). Unfortunately, the available anti-CDI drugs are limited. Recent guidelines recommend fidaxomicin and vancomycin as first-line drugs to treat CDI, bezlotoxumab to prevent recurrence, and faecal microbiota transplantation for rescue treatment. Currently, researchers are investigating therapeutic antibacterial drugs (e.g. teicoplanin, ridinilazole, ibezapolstat, surotomycin, cadazolid, and LFF571), preventive medications against recurrence (e.g. Rebyota, Vowst, VP20621, VE303, RBX7455, and MET-2), primary prevention strategies (e.g. vaccine, ribaxamase, and DAV132) and other anti-CDI medications in the preclinical stage (e.g. Raja 42, Myxopyronin B, and bacteriophage). This narrative review summarises current medications, including newly marketed drugs and products in development against CDI, to help clinicians treat CDI appropriately and to call for more research on innovation.

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.

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.

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.

Clostridioides difficile infection is associated with differences in transcriptionally active microbial communities

Clostridioides difficile infection (CDI) is responsible for around 300,000 hospitalizations yearly in the United States, with the associated monetary cost being billions of dollars. Gut microbiome dysbiosis is known to be important to CDI. To the best of our knowledge, metatranscriptomics (MT) has only been used to characterize gut microbiome composition and function in one prior study involving CDI patients. Therefore, we utilized MT to investigate differences in active community diversity and composition between CDI+ (n = 20) and CDI- (n = 19) samples with respect to microbial taxa and expressed genes. No significant (Kruskal-Wallis, p > 0.05) differences were detected for richness or evenness based on CDI status. However, clustering based on CDI status was significant for both active microbial taxa and expressed genes datasets (PERMANOVA, p ≤ 0.05). Furthermore, differential feature analysis revealed greater expression of the opportunistic pathogens Enterocloster bolteae and Ruminococcus gnavus in CDI+ compared to CDI- samples. When only fungal sequences were considered, the family Saccharomycetaceae expressed more genes in CDI-, while 31 other fungal taxa were identified as significantly (Kruskal-Wallis p ≤ 0.05, log(LDA) ≥ 2) associated with CDI+. We also detected a variety of genes and pathways that differed significantly (Kruskal-Wallis p ≤ 0.05, log(LDA) ≥ 2) based on CDI status. Notably, differential genes associated with biofilm formation were expressed by C. difficile. This provides evidence of another possible contributor to C. difficile's resistance to antibiotics and frequent recurrence in vivo. Furthermore, the greater number of CDI+ associated fungal taxa constitute additional evidence that the mycobiome is important to CDI pathogenesis. Future work will focus on establishing if C. difficile is actively producing biofilms during infection and if any specific fungal taxa are particularly influential in CDI.

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.

SER-109 (VOWST™): A Review in the Prevention of Recurrent Clostridioides difficile Infection

SER-109 (VOWST™; fecal microbiota spores, live-brpk) is a live biotherapeutic product indicated to prevent the recurrence of Clostridioides difficile infection (CDI) in patients 18 years of age and older following standard of care (SOC) antibacterial treatment for recurrent CDI. It is a purified bacterial spore suspension sourced from healthy donors. As the first oral faecal microbiota product approved for prevention of recurrent CDI, SER-109 is administered as four capsules once daily for three consecutive days. In a well-designed, placebo-controlled, phase III trial (ECOSPOR III), SER-109 significantly reduced the risk of recurrent CDI at 8 weeks post-treatment, with a durable response seen at 6 months post-treatment. Treatment with SER-109 was also associated with rapid and steady improvement in health-related quality of life compared with placebo. SER-109 was generally well tolerated, with a safety profile similar to that of placebo. The most common adverse events were of mild to moderate severity and generally gastrointestinal in nature. Thus, with the convenience of oral administration and lack of necessity for cold storage, SER-109 is a valuable option for preventing further CDI recurrence in adults following antibacterial treatment for recurrent CDI.

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.

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 infection after extracorporeal membrane oxygenation support for acute myocardial infarction: a case report

Introduction

Restored cardiopulmonary function is efficiently achieved by utilizing extracorporeal membrane oxygenation (ECMO). Nevertheless, the incidence of Clostridioides difficile infection (CDI) associated with ECMO is relatively uncommon.

Case presentation

In this report, we present the case of a 59-year-old male with severe chest pain due to acute myocardial infarction, subsequently necessitating ECMO support. During the first day of hospitalization, pulmonary infections were observed, and piperacillin-tazobactam was prescribed for 7 days at low dosages. However, the patient developed severe diarrhea 4 days later. After ruling out common pathogens, we suspected the occurrence of CDI and performed genetic testing for C. difficile toxin, confirming our diagnosis. The prescription of vancomycin resulted in slight improvement, while fecal microbiota transplantation (FMT) proved to be more effective.

Conclusion

In this case, temporary application of ECMO was applied, and the anti-infective treatment relied on the use of antibiotics at short-term, low-dose, and low CDI risk. Hence, the occurrence of CDI was considered an uncommon event, which may serve as a reference for future cases.

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.

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.

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.

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.

Managing the clinical effects of drug-induced intestinal dysbiosis with a focus to antibiotics: Challenges and opportunities

The term "intestinal dysbiosis" is used for indicating change(s) of the intestinal microbiota which have been associated with the development of diseases and the deterioration of disease treatments in humans. In this review, documented clinical effects of drug-induced intestinal dysbiosis are briefly presented, and methodologies which could be considered for the management of drug-induced intestinal dysbiosis based on clinical data are critically reviewed. Until relevant methodologies are optimized and/or their effectiveness to the general population is confirmed, and, since drug-induced intestinal dysbiosis refers predominantly to antibiotic-specific intestinal dysbiosis, a pharmacokinetically-based approach for mitigating the impact of antimicrobial therapy on intestinal dysbiosis is proposed.

Fecal microbiota transplantation in childhood: past, present, and future

BACKGROUND

Fecal microbiota transplantation (FMT) has been well described in the treatment of pediatric diseases; however, the latest updates regarding its use in children are unclear and the concepts involved need to be revisited.

DATA SOURCES

We performed advanced searches in the MEDLINE, EMBASE, and Cochrane databases using the keywords "Fecal microbiota transplantation OR Fecal microbiota transfer" in the [Title/Abstract] to identify relevant articles published in English within the last five years. To identify additional studies, reference lists of review articles and included studies were manually searched. Retrieved manuscripts (case reports, reviews, and abstracts) were assessed by the authors.

RESULTS

Among the articles, studies were based on the mechanism (n = 28), sample preparation (n = 9), delivery approaches (n = 23), safety (n = 26), and indications (n = 67), including Clostridium difficile infection (CDI) and recurrent C. difficile infection (rCDI; n = 21), non-alcoholic fatty liver disease (NAFLD; n = 10), irritable bowel syndrome (IBS; n = 5), inflammatory bowel disease (IBD; n = 15), diabetes (n = 5), functional constipation (FC; n = 4), and autism spectrum disorder (ASD; n = 7).

CONCLUSIONS

Concepts of FMT in pediatric diseases have been updated with respect to underlying mechanisms, methodology, indications, and safety. Evidence-based clinical trials for the use of FMT in pediatric diseases should be introduced to resolve the challenges of dosage, duration, initiation, and the end point of treatment.

Systems-ecology designed bacterial consortium protects from severe Clostridioides difficile infection

Fecal Microbiota Transplant (FMT) is an emerging therapy that has had remarkable success in treatment and prevention of recurrent Clostridioides difficile infection (rCDI). FMT has recently been associated with adverse outcomes such as inadvertent transfer of antimicrobial resistance, necessitating development of more targeted bacteriotherapies. To address this challenge, we developed a novel systems biology pipeline to identify candidate probiotic strains that would be predicted to interrupt C. difficile pathogenesis. Utilizing metagenomic characterization of human FMT donor samples, we identified those metabolic pathways most associated with successful FMTs and reconstructed the metabolism of encoding species to simulate interactions with C. difficile . This analysis resulted in predictions of high levels of cross-feeding for amino acids in species most associated with FMT success. Guided by these in silico models, we assembled consortia of bacteria with increased amino acid cross-feeding which were then validated in vitro . We subsequently tested the consortia in a murine model of CDI, demonstrating total protection from severe CDI through decreased toxin levels, recovered gut microbiota, and increased intestinal eosinophils. These results support the novel framework that amino acid cross-feeding is likely a critical mechanism in the initial resolution of CDI by FMT. Importantly, we conclude that our predictive platform based on predicted and testable metabolic interactions between the microbiota and C. difficile led to a rationally designed biotherapeutic framework that may be extended to other enteric infections.

Therapeutics for Clostridioides difficile infection: molecules and microbes

INTRODUCTION

Clostridioides difficile infection (CDI) is a major healthcare problem in the developed world, and effective management of recurrent infection remains one of the biggest challenges. Several advances have occurred in the management of CDI, and in the last 15 years, multiple new agents have been tested. Since 2011, four new products have been approved by the US FDA for treatment of CDI or prevention of recurrent CDI.

AREAS COVERED

This review focuses on therapeutics of CDI and includes sections on primary prevention, management of active infection, and prevention of recurrent CDI. Specifically, data are included on fecal microbiota transplantation and live biotherapeutics. A comprehensive search of several databases including Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, and Daily, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus from inception to 1 May 2023 was conducted.

EXPERT OPINION

Metronidazole is no longer advised for management of outpatient CDI. The preferred medication of choice for a first episode is oral vancomycin or fidaxomicin. For those patients who recur after the first episode, vancomycin taper pulse or fidaxomicin can be used. Intravenous bezlotoxumab, a monoclonal antibody, is available to prevent recurrences. There are now two FDA-approved microbiome-based therapies or live biotherapeutics for prevention of recurrent CDI, for any recurrent CDI and not necessarily multiply recurrent C difficile. Fecal microbiota transplantation remains available in limited settings for recurrent CDI.

Evaluation of Surface Modified Live Biotherapeutic Products for Oral Delivery

Live biotherapeutic products (LBPs), including symbiotic and genetically engineered bacteria, are a promising class of emerging therapeutics that are widely investigated both preclinically and clinically for their oral delivery to the gastrointestinal (GI) tract. One emergent delivery strategy involves the direct functionalization of LBP surfaces through noncovalent or covalent modifications to control LBP interactions with the GI microenvironment, thereby improving their viability, attachment, or therapeutic effect. However, unlike other therapeutic modalities, LBPs are living organisms which present two unique challenges for surface modifications: (1) this approach can directly interfere with key LBP biological processes (e.g., colonization, metabolite secretion) and (2) modification can be variable due to the dynamic nature of LBP surfaces. Collectively, these factors remain uncharacterized as they relate to the oral delivery of LBPs. Herein, we leverage our previously reported surface modification platform, which enables LBP surface-presentation of targeting ligands, to broadly evaluate and characterize surface modifications on LBPs. Specifically, we evaluate how LBP growth affects the dilution of surface-presented targeting ligands and the subsequent loss of specific target attachment over time. Next, we describe key surface modification parameters (e.g., concentration, residence time) that can be optimized to facilitate LBP target attachment. We then characterize how bioconjugation influences the suitability of LBPs for oral delivery by evaluating their growth, viability, storage, toxicity against mammalian cells, and in vivo colonization. Broadly, we describe key parameters that influence the performance of surface modified LBPs and subsequently outline an experimental pipeline for characterizing and evaluating their suitability for oral delivery.

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.

Treating Clostridioides difficile: Could Microbiota-based Live Biotherapeutic Products Provide the Answer?

Clostridioides difficile infection (CDI) is a pressing health care issue due to the limited effectiveness of current treatments and high recurrence rates. Current available antibiotic options for CDI disrupt the fecal microbiome which predisposes recurrent CDI. Fecal microbiota transplantation (FMT) has improved the outcomes of recurrent CDI, but concerns surrounding the safety and standardization of the product persist. Microbiota-based live biotherapeutic products (LBPs), are emerging as potential alternatives to FMT for CDI treatment. This review explores the potential of LBPs as safe and effective therapy for CDI. While preclinical and early clinical studies have shown promising results, further research is necessary to determine the optimal composition and dosage of LBPs and to ensure their safety and efficacy in clinical practice. Overall, LBPs hold great promise as a novel therapy for CDI and warrant further investigation in other conditions related to disruption of the colonic microbiota.

Emerging Options for the Prevention and Management of Clostridioides difficile Infection

Agents in development for the prevention or treatment of Clostridioides difficile infection can be split into three broad categories: antibiotics, microbiome restoration, and vaccines. Given the extensive list of agents currently in development, this narrative review will focus on agents that have progressed into late-stage clinical trials, defined as having a Phase III clinical trial registered on ClinicalTrials.gov. These agents include one antibiotic (ridinilazole), three live biotherapeutic products (LBPs) (CP101, RBX2660, and SER109), and two toxoid vaccines (PF06425090 and a second toxoid vaccine). As new prevention and treatment strategies enter the market, clinicians and administrators will need knowledge of these products to make rational decisions on how best to adopt them into clinical practice.

The In Vitro Efficacy of Activated Charcoal in Fecal Ceftriaxone Adsorption among Patients Who Received Intravenous Ceftriaxone

Broad-spectrum antibiotics can kill both pathogens and gut microbiota. Reducing exposure to excess intestinal antibiotics could theoretically protect gut microbiota homeostasis. Recently, engineered charcoals, gel microparticles, and resin beads have demonstrated efficacy in intestinal antibiotic adsorption in animal studies. We report the first in vitro study evaluating human fecal antibiotic adsorption efficacy of conventional activated charcoal (AC). We collected fecal samples from eight patients who received intravenous (IV) ceftriaxone after admission to King Chulalongkorn Memorial Hospital, Thailand, during January−March 2020. Fecal ceftriaxone was measured by indirect competitive enzyme-linked immunoassays. Three different doses of AC were mixed with fecal samples under a specified protocol. The geometric mean reduction in fecal ceftriaxone concentration when mixed with AC 30 mg/g feces was 0.53 (95% CI 0.33−0.85, p-value < 0.001), meaning 47% adsorption efficacy. Increased adsorption was found with higher doses, 71% and 87% for AC 150 and 500 mg/g feces, respectively. In conclusion, the usual food-poisoning-care dose of conventional AC, 30 mg/g feces, demonstrated dose-dependent and significant fecal ceftriaxone adsorption. Conventional oral AC might be a pragmatic and inexpensive option for the protection of gut microbiota in patients receiving IV ceftriaxone. However, in vivo studies and microbiome analysis are needed for further evidence.

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.

Microbiota of the gastrointestinal tract: Friend or foe?

The gut microbiota is currently considered an external organ of the human body that provides important mechanisms of metabolic regulation and protection. The gut microbiota encodes over 3 million genes, which is approximately 150 times more than the total number of genes present in the human genome. Changes in the qualitative and quantitative composition of the microbiome lead to disruption in the synthesis of key bacterial metabolites, changes in intestinal barrier function, and inflammation and can cause the development of a wide variety of diseases, such as diabetes, obesity, gastrointestinal disorders, cardiovascular issues, neurological disorders and oncological concerns. In this review, I consider issues related to the role of the microbiome in the regulation of intestinal barrier function, its influence on physiological and pathological processes occurring in the body, and potential new therapeutic strategies aimed at restoring the gut microbiome. Herewith, it is important to understand that the gut microbiota and human body should be considered as a single biological system, where change of one element will inevitably affect its other components. Thus, the study of the impact of the intestinal microbiota on health should be considered only taking into account numerous factors, the role of which has not yet been fully elucidated.

Advancing therapeutics for recurrent clostridioides difficile infections: an overview of vowst's FDA approval and implications

Clostridioides difficile infections (CDI) are a leading cause of healthcare-associated infections with a high relapse rate. Current treatment guidelines recommend fidaxomicin as the primary therapy for initial CDI episodes and suggest alternative approaches for recurrent episodes, including fecal microbiota transplantation (FMT). This paper explores the recent approval of Vowst, a novel oral FMT drug, by the United States Food and Drug Administration (FDA) as a prophylactic therapy to prevent recurrent CDIs. Vowst comprises a formulation of live fecal microbiota spores and works by reestablishing the disrupted gut microbiota, limiting C. difficile spore germination, and promoting microbiome repair. Furthermore, this paper will discuss the product's approval journey and the uncertainties regarding its efficacy in CDI patients beyond the ones who participated in the clinical trials, pharmacovigilance, cost estimates, and the need for a more stringent donor screening process. Overall, Vowst's approval marks a significant step forward in the prevention of recurrent CDI infections with various beneficial implications for future gastroenterology.

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.

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.

Gut microbiota modulates lung fibrosis severity following acute lung injury in mice

Independent studies demonstrate the significance of gut microbiota on the pathogenesis of chronic lung diseases; yet little is known regarding the role of the gut microbiota in lung fibrosis progression. Here we show, using the bleomycin murine model to quantify lung fibrosis in C57BL/6 J mice housed in germ-free, animal biosafety level 1 (ABSL-1), or animal biosafety level 2 (ABSL-2) environments, that germ-free mice are protected from lung fibrosis, while ABSL-1 and ABSL-2 mice develop mild and severe lung fibrosis, respectively. Metagenomic analysis reveals no notable distinctions between ABSL-1 and ABSL-2 lung microbiota, whereas greater microbial diversity, with increased Bifidobacterium and Lactobacilli, is present in ABSL-1 compared to ABSL-2 gut microbiota. Flow cytometric analysis reveals enhanced IL-6/STAT3/IL-17A signaling in pulmonary CD4 + T cells of ABSL-2 mice. Fecal transplantation of ABSL-2 stool into germ-free mice recapitulated more severe fibrosis than transplantation of ABSL-1 stool. Lactobacilli supernatant reduces collagen 1 A production in IL-17A- and TGFβ1-stimulated human lung fibroblasts. These findings support a functional role of the gut microbiota in augmenting lung fibrosis severity.

Commercially Available Enteric Empty Hard Capsules, Production Technology and Application

Currently, there is a growing need to prepare small batches of enteric capsules for individual therapy or clinical evaluation since many acidic-sensitive substances should be protected from the stomach's acidic environment, including probiotics or fecal material, in the fecal microbiota transplantation (FMT) process. A suitable method seems to be the encapsulation of drugs or lyophilized alternatively frozen biological suspensions in commercial hard enteric capsules prepared by so-called Enteric Capsule Drug Delivery Technology (ECDDT). Manufacturers supply these types of capsules, made from pH-soluble polymers, in products such as AR Caps®, EnTRinsicTM, and Vcaps® Enteric, or capsules made of gelling polymers that release their content as the gel erodes over time when passing through the digestive tract. These include DRcaps®, EMBO CAPS® AP, BioVXR®, or ACGcaps™ HD. Although not all capsules in all formulations meet pharmaceutical requirements for delayed-release dosage forms in disintegration and dissolution tests, they usually find practical application. This literature review presents their composition and properties. Since ECDDT is a new technology, this article is based on a limited number of references.

Peroxisome proliferator-activated receptor-γ as the gatekeeper of tight junction in Clostridioides difficile infection

Clostridioides difficile is a major causative pathogen of nosocomial antibiotic-associated diarrhea and severe colitis. Despite the use of vancomycin and fidaxomicin as standard drugs for the treatment of C. difficile infection (CDI), clinical relapse rates remain high. Therefore, new alternative therapeutics to treat CDI are urgently required. The nuclear receptor, peroxisome proliferator-activated receptor-γ (PPAR-γ), is mainly expressed in the adipose tissue and modulates lipid metabolism and insulin sensitization. Previous studies have shown that PPAR-γ is highly expressed in colonic tissues and regulates tight junction function in epithelial cells. However, the role of PPAR-γ in CDI pathogenesis remains unclear. In this study, we used a mouse model of CDI and found that both expression levels of PPAR-γ and the tight junction protein, occludin, were decreased in colonic tissues. Furthermore, to investigate the role of PPAR-γ in CDI, we used PPAR-γ defective mice and found that intestinal permeability and bacterial dissemination in these mice were significantly higher than those in wild-type mice during CDI. Administration of the PPAR-γ agonist, pioglitazone, to activate PPAR-γ activity improved the phenotypes of CDI, including bodyweight loss, inflammation, and intestinal integrity. Taken together, these results demonstrate that PPAR-γ is a potential therapeutic target in CDI, as it modulates colonic inflammation and integrity.

Fecal microbiota transplantation as a promising treatment option for osteoporosis

Osteoporosis is a systemic metabolic bone disease characterized by the descending bone mass and destruction of bone microstructure, which tends to result in the increased bone fragility and associated fractures, as well as high disability rate and mortality. The relation between gut microbiota and bone metabolism has gradually become a research hotspot, and it has been verified that gut microbiota is closely associated with reduction of bone mass and incidence of osteoporosis recently. As a novel "organ transplantation" technique, fecal microbiota transplantation (FMT) mainly refers to the transplantation of gut microbiota from healthy donors to recipients with gut microbiota imbalance, so that the gut microbiota in recipients can be reshaped and play a normal function, and further prevent or treat the diseases related to gut microbiota disorder. Herein, based on the gut-bone axis and proven regulatory effects of gut microbiota on osteoporosis, this review expounds relevant basic researches and clinical practice of FMT on osteoporosis, thus demonstrating the potentials of FMT as a therapeutic option for osteoporosis and further providing certain reference for the future researches.

Exploratory studies of oral and fecal microbiome in healthy human aging

Growing evidence has linked an altered host fecal microbiome composition with health status, common chronic diseases, and institutionalization in vulnerable older adults. However, fewer studies have described microbiome changes in healthy older adults without major confounding diseases or conditions, and the impact of aging on the microbiome across different body sites remains unknown. Using 16S ribosomal RNA gene sequencing, we reconstructed the composition of oral and fecal microbiomes in young (23-32; mean = 25 years old) and older (69-94; mean = 77 years old) healthy community-dwelling research subjects. In both body sites, we identified changes in minor bacterial operational taxonomic units (OTUs) between young and older subjects. However, the composition of the predominant bacterial species of the healthy older group in both microbiomes was not significantly different from that of the young cohort, which suggests that dominant bacterial species are relatively stable with healthy aging. In addition, the relative abundance of potentially pathogenic genera, such as Rothia and Mycoplasma, was enriched in the oral microbiome of the healthy older group relative to the young cohort. We also identified several OTUs with a prevalence above 40% and some were more common in young and others in healthy older adults. Differences with aging varied for oral and fecal samples, which suggests that members of the microbiome may be differentially affected by aging in a tissue-specific fashion. This is the first study to investigate both oral and fecal microbiomes in the context of human aging, and provides new insights into interactions between aging and the microbiome within two different clinically relevant sites.

SER-109: An Oral Investigational Microbiome Therapeutic for Patients with Recurrent Clostridioides difficile Infection (rCDI)

Clostridioides difficile infection (CDI) is classified as an urgent health threat by the Centers for Disease Control and Prevention (CDC), and affects nearly 500,000 Americans annually. Approximately 20−25% of patients with a primary infection experience a recurrence, and the risk of recurrence increases with subsequent episodes to greater than 40%. The leading risk factor for CDI is broad-spectrum antibiotics, which leads to a loss of microbial diversity and impaired colonization resistance. Current FDA-approved CDI treatment strategies target toxin or toxin-producing bacteria, but do not address microbiome disruption, which is key to the pathogenesis of recurrent CDI. Fecal microbiota transplantation (FMT) reduces the risk of recurrent CDI through the restoration of microbial diversity. However, FDA safety alerts describing hospitalizations and deaths related to pathogen transmission have raised safety concerns with the use of unregulated and unstandardized donor-derived products. SER-109 is an investigational oral microbiome therapeutic composed of purified spore-forming Firmicutes. SER-109 was superior to a placebo in reducing CDI recurrence at Week 8 (12% vs. 40%, respectively; p < 0.001) in adults with a history of recurrent CDI with a favorable observed safety profile. Here, we discuss the role of the microbiome in CDI pathogenesis and the clinical development of SER-109, including its rigorous manufacturing process, which mitigates the risk of pathogen transmission. Additionally, we discuss compositional and functional changes in the gastrointestinal microbiome in patients with recurrent CDI following treatment with SER-109 that are critical to a sustained clinical response.