Khanna, S

Background: Clostridioides difficile infection (CDI) is well-recognised as a cause of flare in inflammatory bowel disease (IBD). Objectives: To prospectively evaluate CDI as a cause of flare in moderate-to-severe ulcerative colitis (UC) and perform a region-specific systematic review to evaluate the role of CDI in IBD patients in South Asia. Design: A single-centre prospective observational study followed by a region-specific systematic review. Data sources and methods: The observational study was conducted between December 2024 and December 2025 and included patients with moderate-to-severe UC flares. Triple testing using Stool glutamate dehydrogenase (GDH), an enzyme immunoassay (EIA) for toxin A/B, and polymerase chain reaction (PCR) testing was performed. A literature search in PubMed, Embase, and Scopus was conducted on 5th December 2025 to identify relevant studies from South Asia. Information on the study population (IBD type, age, gender, disease activity), the testing method, and the outcomes of CDI testing were extracted. The pooled prevalence of CDI was estimated using a random-effects model. The risk of Bias was assessed using Joanna Briggs’ tool. Results: Of the 101 patients with active UC, 59 had acute severe UC. Six patients tested positive for GDH, whereas only one tested positive for EIA and PCR. A total of 13 studies reporting on 1267 patients were included in the systematic review. Pooled prevalence of CDI was 0.06 (0.03–0.11, I 2 = 80.8%). Subgroup analyses were performed by testing method, study type, and region. However, there was persistent statistical heterogeneity. Funnel plot and Egger’s test suggested the presence of publication bias. Conclusion: Our observational study shows a low prevalence of CDI as a cause of UC flares. The findings of the systematic review suggest high variability in the CDI positivity across South Asia. These differences were not fully explained by the method of testing, the type of study, or the geographic location of the study.

INTRODUCTION: Clostridioides difficile infection (CDI) presents a significant challenge in patients with inflammatory bowel disease (IBD), with high recurrence rates and complications. Predicting recurrent CDI (rCDI) in patients with IBD is crucial for implementing targeted interventions to improve patient outcomes. This study aimed to develop and validate a predictive model (RecurCDI-IBD) using supervised machine learning to identify patients with IBD at high risk of developing rCDI. METHODS: Data were collected from adult patients with IBD diagnosed with CDI between 2013 and 2021. Inclusion criteria included adult patients with a confirmed diagnosis of CDI and a history of IBD. The Gradient Boosting Machine learning model (XGBoost) was used to train a binary classification model. Feature engineering included demographic data (age and sex), clinical data (IBD subtype, medication use, and comorbidities), and laboratory data. The primary outcome was the occurrence of rCDI within 60 days of the initial CDI episode. RESULTS: The RecurCDI-IBD model achieved an accuracy of 80.05% and an Area Under the Curve of 0.88 for predicting rCDI. Key predictive features included IBD subtype, sex, specific medications (such as steroids and anti-TNF agents), and comorbidities (such as chronic pulmonary and renal disease). DISCUSSION: The RecurCDI-IBD model demonstrates good discriminatory ability with balanced precision and recall in identifying patients with IBD at higher risk for rCDI. These findings highlight the potential of data-driven approaches to support clinical risk assessment. Further studies incorporating larger and more diverse cohorts and prospective external validation are needed to confirm generalizability and optimize clinical applicability.

Background: Recurrent Clostridioides difficile infection (rCDI) disrupts health-related quality of life (HRQoL), often causing debilitating symptoms, emotional distress, and social withdrawal. Fecal microbiota, live-jslm (RBL; REBYOTA ® ) is approved by the FDA to reduce CDI recurrence. While the burden of rCDI is well established, less is known about the patient experience after RBL treatment and its impact on HRQoL. Objectives: To explore the burden of rCDI on HRQoL, and any improvements in symptoms and impacts after RBL administration by colonoscopy. Design: A qualitative sub-study embedded in the CDI-SCOPE phase IIIb clinical trial (NCT05831189). Methods: Qualitative interviews were conducted with 30 trial participants approximately 8 weeks after RBL treatment. Interviews were conducted using a semi-structured discussion guide; they were audio-recorded, transcribed verbatim, and thematically analyzed. Results: Thirty of 41 trial participants (73%) took part in the qualitative interviews (July 2023–September 2024). Participants (mean age 59 years; 87% female) had experienced multiple prior rCDI episodes. Before RBL treatment, participants reported severe symptoms, including diarrhea (30/30; 100%), abdominal pain (21/30; 70%), and fatigue (14/30; 47%), which negatively affected daily life, social interactions, and emotional health. Eight weeks after RBL treatment, no participants reported a recurrence. Diarrhea symptoms resolved (17/30; 57%) or improved (13/30; 43%) for all participants, typically within 1 month. Average severity scores for diarrhea declined markedly (from 8.9 to 1.3). Every participant (100%) reported improved ability to engage in daily activities; nearly all (29/30; 97%) described positive changes to social life/relationships, and 77% (23/30) reported improved emotional well-being. Conclusion: RBL administered via colonoscopy provided rapid, meaningful relief from rCDI symptoms, and due to symptom improvements, many participants reported that they were able to resume daily life. These findings highlight the broader value of RBL in restoring HRQoL and overall well-being. Trial registration: ClinicalTrials.gov: NCT05831189.

Abstract Background The term “incomplete microscopic colitis” (MCi) has been suggested to define patients with chronic watery diarrhea not fulfilling the complete histologic criteria for MC. There are inconsistent data on the epidemiology of MCi and the optimal management of these patients. Methods A systematic search of randomized control trials (RCTs) and observational studies of adults with biopsy-proven MCi (incomplete lymphocytic colitis and collagenous colitis) was conducted using Cochrane, Medline, Scopus, and Embase from inception to May 6, 2025. Data were extracted on (1) incidence and prevalence of MCi, (2) patient features and risk factors, (3) clinical response with treatment, and (4) relapse after treatment cessation. Data were pooled using the random-effects model to calculate weighted pooled estimates and 95% confidence intervals (CIs). Results Of 136 potentially relevant publications identified, 49 passed abstract screening, and 17 studies (1 RCT and 16 observational) were included, with a total of 1370 patients with MCi (median age of 62 years and 69.6% women). The incidence rate of MCi ranged from 0.96 to 5.0 cases per 100 000 person-years. The pooled proportion of concurrent autoimmune disease with MCi was 18% (95% confidence interval [CI], 0.07-0.28; I2 = 95%), and 46% (95% CI, 0.28-0.64; I2 = 95%) were on medications associated with microscopic colitis (MC). The pooled clinical remission rate with any induction therapy was 78% (95% CI, 0.68-0.89; I2 = 81%) and 85% (95% CI, 0.72-0.98; I2 = 88%) with budesonide. Conclusions Patients with MCi share similar characteristics with full MC including demographics, risk factors, and response to therapy, indicating that the histologic criteria for MC should potentially be broadened.

Background: Clostridioides difficile infection (CDI) treated with bezlotoxumab (BEZ) has been demonstrated to have a lower recurrence rate than placebo in clinical trials. However, real-world data on BEZ’s effectiveness remain limited and heterogeneous. Objectives: To evaluate the real-world effectiveness of BEZ in preventing CDI recurrence through a single-center retrospective cohort and a meta-analysis. Design: A retrospective cohort study and a meta-analysis. Methods: A retrospective study of patients treated with BEZ from 2017 to 2021 was performed at the Mayo Clinic. Demographics, CDI diagnostics, and several prespecified risk factors were analyzed. A literature search was conducted in August 2024 utilizing the Cochrane Central Register of Controlled Trials, Embase, Medline, Scopus, and Web of Science Core Collection. Studies reporting CDI resolution rates with BEZ were included. The random-effects model described by DerSimonian and Laird was used to calculate weighted pooled resolution rates (WPR) with 95% confidence intervals (CI). We assessed heterogeneity with the inconsistency index ( I 2 ) statistic. Results: Across 28 studies and our retrospective cohort, 2639 CDI patients were analyzed. Among 1786 patients treated with BEZ, 1450 achieved clinical resolution (WPR: 81.6%, 95% CI 77.2–85.6%), with significant heterogeneity ( I ² = 77.3%). In subgroup analysis, the pooled relative risk of recurrence was 0.56 (95% CI 0.36–0.88; p < 0.01) for BEZ with SoC compared to SoC alone. A WPR of 83.3% (95% CI 75.5%–91.1%) for patients receiving BEZ with SoC was observed when compared with a WPR of 70.8% (95% CI 62.7%–78.8%) in patients receiving SoC alone on subgroup analysis. In our cohort of 47 patients, the CDI resolution rate was 72.3% (34/47). Conclusion: Our retrospective study and meta-analysis demonstrate the real-world efficacy of BEZ in reducing CDI recurrence. The higher recurrence rates in our cohort likely reflect the high-risk nature of the population, including a greater proportion of immunocompromised patients.

Abstract Background The aim of this study was to evaluate the safety and efficacy of fecal microbiota, live-jslm (RBL; REBYOTA)—the first single-dose, broad consortia microbiota-based live biotherapeutic approved by the US Food and Drug Administration for preventing recurrent Clostridioides difficile infection (rCDI) in adults following standard-of-care (SOC) antibiotic treatment. Methods PUNCH CD3-OLS was a prospective, phase 3, open-label study, conducted across the US and Canada. Participants were aged ≥18 years with documented rCDI and confirmed use of SOC antibiotics. Participants with comorbidities including inflammatory bowel disease and mild-to-moderate immunocompromising conditions could be enrolled. A single dose of RBL was rectally administered within 24–72 hours of antibiotic completion. The primary endpoint was the number of participants with RBL- or administration-related treatment-emergent adverse events (TEAEs). Secondary endpoints included treatment success and sustained clinical response, at 8 weeks and 6 months after RBL administration, respectively. Results Overall, 793 participants were enrolled, of whom 697 received RBL. TEAEs through 8 weeks after administration were reported by 47.3% of participants; most events were mild or moderate gastrointestinal disorders. Serious TEAEs were reported by 3.9% of participants. The treatment success rate at 8 weeks was 73.8%; in participants who achieved treatment success, the sustained clinical response rate at 6 months was 91.0%. Safety and efficacy rates were similar across demographic and baseline characteristic subgroups. Conclusions RBL was safe and efficacious in participants with rCDI and common comorbidities. This is the largest microbiota-based live biotherapeutic study to date, and findings support use of RBL to prevent rCDI in a broad patient population. Clinical Trials Registration NCT03931941.

INTRODUCTION: Bile acid sequestrants (BAS) are an option for microscopic colitis (MC) refractory or intolerant to budesonide. There are inconsistent data on the prevalence of bile acid malabsorption (BAM) and utility of bile acid testing in MC. The aim of this systematic review and meta-analysis was to evaluate these outcomes. METHODS: A systematic search of randomized control trials and observational studies of adults with MC treated with BAS was conducted using MEDLINE, Embase, Cochrane, and Scopus from inception to January 22, 2024. Data were extracted on (i) prevalence of BAM, (ii) clinical response and adverse events, and (iii) recurrence after BAS discontinuation. Data were pooled using random-effects models to determine weighted pooled estimates and 95% confidence intervals (CIs). RESULTS: We included 23 studies (1 randomized control trial, 22 observational), with 1,011 patients with MC assessed for BAM and 771 treated with BAS. The pooled prevalence of BAM was 34% (95% CI 0.26–0.42, I 2 = 81%). The pooled response rate with BAS induction for all patients with MC, irrespective of BAM, was 62% (95% CI 0.55–0.70, I 2 = 71%). There was a higher pooled response rate in patients with BAM compared with those without BAM ( P < 0.0001). The pooled rate of BAS-related adverse effects was 9% (95% CI 0.05–0.14, I 2 = 58%). DISCUSSION: One-third of patients with MC had BAM, and almost two-thirds of all patients responded to BAS with limited side effects. Patients with MC and BAM were more likely to respond to therapy, supporting the value of bile acid testing.

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.

The species composition of the human gut microbiota is related to overall health, and a healthy gut microbiome is crucial in maintaining colonization resistance against pathogens. Disruption of gut microbiome composition and functionality reduces colonization resistance and has been associated with several gastrointestinal and non-gastrointestinal diseases. One prime example is Clostridioides difficile infection (CDI) and subsequent recurrent infections that occur after the development of systemic antibiotic-related dysbiosis. Standard-of-care antibiotics used for both acute and recurrent infections do not address dysbiosis and often worsen the condition. Moreover, monoclonal antibodies, recommended in conjunction with standard-of-care antibiotics for the prevention of recurrent CDI in patients at high risk of recurrence, reduce recurrences but do not address the underlying dysbiosis. Fecal microbiota transplantation (FMT) is an evolving therapeutic strategy in which microbes are harvested from healthy donor stool and transplanted into the gut of a recipient to restore the gut microbiome. Although effective in the prevention of recurrent CDI, some existing challenges include screening and the standardization of stool acquisition and processing. Recent safety alerts by the US Food and Drug Administration raised concern about the possibility of transmission of multidrug-resistant organisms or severe acute respiratory syndrome coronavirus 2 via FMT. Increased knowledge that microbes are beneficial in restoring the gut microbiome has led to the clinical development of several newer biotherapeutic formulations that are more regulated than FMT, which may allow for improved restoration of the gut microbiome and prevention of CDI recurrence. This review focuses on mechanisms by which gut microbiome restoration could influence colonization resistance against the pathogen C. difficile. Plain language summary The Role of the Gut Microbiome in Clostridioides difficile Infection Introduction: A rich and diverse gut microbiome is key to immune system regulation and colonization resistance against pathogens. A disruption in the gut microbiome composition can make the gut more vulnerable to diseases such as Clostridioides difficile infection (CDI), caused by the bacterium C. difficile. CDI management presents a therapeutic dilemma, as it is usually treated with antibiotics that can treat the infection but also can damage the microbiome. Treatment of CDI using antibiotics can further reduce microbial diversity and deplete beneficial bacteria from the gut leading to a condition called dysbiosis. Antibiotic treatment can be followed by therapies that restore the gut microbiota, boost colonization resistance, and prevent the development of antimicrobial resistance. It is important to evaluate treatment options to determine their safety and effectiveness. Methods: The researchers provided an overview of the mechanisms that the gut microbiome uses to prevent colonization of the gut by pathogens. They subsequently reviewed the efficacy and shortcomings of the following treatments for CDI: - Antibiotics - Monoclonal antibodies - Fecal microbiota transplantation (FMT) Results: Commensal intestinal bacteria prevent colonization of the gut by pathogens using mechanisms such as: - Competition for key nutrients - Production of inhibitory bile acids - Short-chain fatty acid production - Lowering the luminal pH - Production of bacteriocins Antibiotic therapy is recommended as a standard treatment for CDI. However, patients are vulnerable to recurrent CDI after discontinuation of the therapy. Monoclonal antibodies that inactivate C. difficile toxins may be recommended along with antibiotics to prevent recurrent CDI. However, this approach does not restore the microbiome. FMT is one method of microbial restoration, where stool is harvested from a healthy donor and transplanted into a patient’s colon. Although FMT has shown some efficacy in the treatment of recurrent CDI, the procedure is not standardized. Safety concerns have been raised about the possibility of transmission of multidrug-resistant pathogens via FMT. Conclusion: Treatment methods that can efficiently restore the diversity of the gut microbiome are crucial in preventing recurrence of CDI.

AbstractClostridioides difficile infection (CDI) is an urgent health threat being the most common healthcare‐associated infection, and its management is a clinical conundrum. Over 450 000 infections are seen in the United States with similar incidence seen in the rest of the developed world. The majority of infections seen are mild–moderate with fulminant disease and mortality being rare complications seen in the elderly and in those with comorbidities. The most common complication of CDI is recurrent infection with rates as high as 60% after three or more infections. A dilemma in the management of primary and recurrent CDI is testing due to the high sensitivity of the nucleic acid amplification tests such as the polymerase chain reaction, which leads to clinical false positives if patients are not chosen carefully (with symptoms) before testing. A newer testing regimen involving a 2‐step strategy is emerging using glutamate dehydrogenase as a screening strategy followed by enzyme immunoassay for the C. difficile toxin. Microbiota restoration therapies are the cornerstone of management of recurrent CDI to prevent future recurrences. The most common modality of microbiota restoration is faecal microbiota transplantation, which has been tainted with heterogeneity and adverse events such as serious infectious transmission. The success rates for recurrence prevention from microbiota restoration therapies are over 90% compared with less than 50% of recurrence prevention with courses of antibiotics. This has led to development and emergence of standardized microbiota restoration therapies in capsule and enema forms. Capsule‐based therapies include CP101 (positive phase II results), RBX7455 (positive phase I results), SER‐109 (positive phase III results) and VE303 (ongoing phase II trial). Enema‐based therapy includes RBX2660 (positive phase III data). This review summarizes the principles of management and diagnosis of CDI and focuses on emerging and existing data on faecal microbiota transplantation and standardized microbiota restoration therapies.