Economic burden and cost-effectiveness of therapies for Clostridiodes difficile infection: a narrative review

Exploring novel microbial metabolites and drugs for inhibiting Clostridioides difficile

Clostridioides difficile is an enteric pathogen that can cause a range of illnesses from mild diarrhea to pseudomembranous colitis and even death. This pathogen often takes advantage of microbial dysbiosis provoked by antibiotic use. With the increasing incidence and severity of infections, coupled with high recurrence rates, there is an urgent need to identify innovative therapies that can preserve the healthy state of the gut microbiota. In this study, we screened a microbial metabolite library against C. difficile. From a collection of 527 metabolites, we identified 18 compounds with no previously identified antimicrobial activity and metabolites that exhibited potent activity against C. difficile growth. Of these 18 hits, five drugs and three metabolites displayed the most potent anti-C. difficile activity and were subsequently assessed against 20 clinical isolates of C. difficile. These potent agents included ecteinascidin 770 (minimum inhibitory concentration against 50% of isolates [MIC50] ≤0.06 µg/mL); 8-hydroxyquinoline derivatives, such as broxyquinoline and choloroquinaldol (MIC50 = 0.125 µg/mL); ionomycin calcium salt, carbadox, and robenidine hydrochloride (MIC50 = 1 µg/mL); and dronedarone and milbemycin oxime (MIC50 = 4 µg/mL). Unlike vancomycin and fidaxomicin, which are the standard-of-care anti-C. difficile antibiotics, most of these metabolites showed robust bactericidal activity within 2-8 h with minimal impact on the growth of representative members of the normal gut microbiota. These results suggest that the drugs and microbial metabolite scaffolds may offer alternative avenues to address unmet needs in C. difficile disease prevention and treatment.

IMPORTANCE

The most frequent infection associated with hospital settings is Clostridioides difficile, which can cause fatal diarrhea and severe colitis, toxic megacolon, sepsis, and leaky gut. Those who have taken antibiotics for other illnesses that affect the gut's healthy microbiota are more susceptible to C. difficile infection (CDI). Recently, some reports showed higher recurrence rates and resistance to anti-C. difficile, which may compromise the efficacy of CDI treatment. Our study is significant because it is anticipated to discover novel microbial metabolites and drugs with microbial origins that are safe for the intestinal flora, effective against C. difficile, and reduce the risk of recurrence associated with CDI.

Rise to the Challenge: Master the Management of Clostridioides difficile Infection

Clostridioides difficile infection (CDI) is a significant public health challenge in the developed world. Although previously CDI was primarily a health care-acquired infection, there are now rising numbers of community-acquired cases in patients without traditional risk factors, such as antibiotic exposure. The landscape for the treatment of CDI has changed significantly during the past decade, including newer diagnostic tests, novel antibiotic regimens, and strategies for microbiome restoration in the form of traditional fecal microbiota transplant and approved live biotherapeutics in an effort to address the underlying pathophysiologic process of gut microbial dysbiosis. We present a concise review for clinicians on the diagnosis and management of both primary and recurrent CDI.

Alternative treatment of recurrent Clostridioides difficile infection in adults by fecal transplantation: an overview of phase I-IV studies from Clinicaltrials.gov

Background

Fecal microbiota transplantation (FMT) is an interventional approach to treat chronic and recurrent Clostridioides difficile infection (CDI). However, there is insufficient evidence regarding its effectiveness and safety. Clinical trials have been conducted to inspect the safety and effectiveness of FMT with and without comparison to pharmacological treatments.

Aim

This review explored the treatment of CDI in adults using FMT and evaluated the safety of this intervention based on phase I-IV studies registered on Clinicaltrials.gov.

Method

A comprehensive search of Clinicaltrials.gov was conducted to identify relevant studies that investigated CDI in adults. Data on study type, study design, sample size, intervention details, and outcomes related to FMT were examined and evaluated.

Results

In total, 13 clinical trials on FMT for CDI published through 17 November 2023 were identified, all of which were interventional studies. The investigation focused on both terminated and completed studies. Basic and advanced outcome measures were examined.

Conclusion

Some studies were terminated during phase II, and FMT was less effective than antibiotics such as vancomycin and fidaxomicin. However, colonoscopy and oral FMT were explored in several completed studies with promising results, but the evidence remains limited and inconclusive.

Clostridioides difficile infection, recurrence and the associated healthcare consumption in Sweden between 2006 and 2019: a population-based cohort study

BACKGROUND

Clostridioides difficile infection (CDI) causes a major burden to individuals and society, yet the impact may vary depending on age, sex, underlying comorbidities and where CDI was acquired (hospital or community).

METHODS

This Swedish nationwide population-based cohort study (2006-2019) compared all 43,150 individuals with CDI to their 355,172 matched controls (first year and entire follow-up). Negative binomial regression models compared the cumulated length of stay, number of in-hospital admissions, outpatient visits and prescriptions after the first CDI episode expressed as incidence rate ratios (IRR) and 95% confidence intervals for the entire follow-up.

RESULTS

Overall, 91.6% of CDI cases were hospital acquired, and 16.8% presented with recurrence(s); 74.8%of cases were ≥ 65 years and 54.2% were women. Compared to individuals without CDI, in-hospital stay rates were 18.01 times higher after CDI (95% CI 17.40-18.63, first-year: 27.4 versus 1.6 days), 9.45 times higher in-hospital admission (95% CI 9.16-9.76, first-year: 2.6 versus 1.3 hospitalisations), 3.94 times higher outpatient visit (95% CI 3.84-4.05, first-year: 4.0 versus 1.9 visits) and 3.39 times higher dispensed prescriptions rates (95% CI 3.31-3.48, first-year: 25.5 versus 13.7 prescriptions). For all outcomes, relative risks were higher among the younger (< 65 years) than the older (≥ 65 years), and in those with fewer comorbidities, but similar between sexes. Compared to those without recurrence, individuals with recurrence particularly showed a higher rate of hospital admissions (IRR = 1.18, 95% 1.12-1.24). Compared to community-acquired CDI, those with hospital-acquired CDI presented with a higher rate of hospital admissions (IRR = 7.29, 95% CI 6.68-7.96) and a longer length of stay (IRR = 7.64, 95% CI 7.07-8.26).

CONCLUSION

CDI was associated with increased health consumption in all affected patient groups. The majority of the CDI burden could be contributed to hospital-acquired CDI (~ 9/10), older patients (~ 3/4) and those with multiple comorbidities (~ 6/10 Charlson score ≥ 3), with 1/5 of the total CDI burden contributed to individuals with recurrence. Yet, relatively speaking the burden was higher among the younger and those with fewer comorbidities, compared to their peers without CDI.

Outcomes of Clostridioides difficile infection in acute heart failure hospitalizations: insights from the National Inpatient Database

BACKGROUND

Heart failure (HF) patients are at a greater risk for nosocomial infections due to their higher prevalence of comorbidities, readmission rates, and prolonged hospital stays. Clostridioides difficile infection (CDI) remains a common nosocomial infection in hospitalized patients.

AIM

To identify patients with a diagnosis of acute HF and stratified based on the presence of CDI, using the National Inpatient Sample (NIS) database from 2016 to 2020.

METHODS

Adjusted odds ratios (aOR) of in-hospital outcomes were calculated, and a propensity-matched analysis was performed.

FINDINGS

Of 536,595 acute HF hospitalizations in this timeframe, 3030 were also diagnosed with CDI (0.56%). Patients with acute HF and CDI had significantly higher in-hospital mortality (adjusted odds ratio: (aOR): 1.91), cardiac arrest (aOR: 1.66), and use of mechanical circulatory support (MCS) (aOR 2.42). In propensity-matched analysis, in-hospital mortality (13.71 vs 8.44%; P=0.005), septic shock (7.54 vs 3.33%; P=0.002), and use of MCS (7.19 vs 3.68%; P=0.009) were significantly higher in HF patients with CDI than without. Coexisting neurological disease (aOR: 3.74) and liver disease (aOR: 2.97) showed the strongest association as independent predictors of mortality. HF patients with CDI had longer hospital stays (14.45 ± 19.40 vs 5.44 ± 7.10 days; P<0.0001) and higher inflation-adjusted total hospital costs ($186,225 ± 376,485 vs $60,740 ± 153,992; P<0.001) compared to those without CDI.

CONCLUSION

The occurrence of concomitant CDI in patients admitted with acute HF exacerbation is associated with worse in-hospital outcomes and deaths as well as longer hospitalizations and greater financial cost.

Treated, hospital-onset Clostridiodes difficile infection: An evaluation of predictors and feasibility of benchmarking comparing 2 risk-adjusted models among 265 hospitals

OBJECTIVES

To evaluate the incidence of a candidate definition of healthcare facility-onset, treated Clostridioides difficile (CD) infection (cHT-CDI) and to identify variables and best model fit of a risk-adjusted cHT-CDI metric using extractable electronic heath data.

METHODS

We analyzed 9,134,276 admissions from 265 hospitals during 2015-2020. The cHT-CDI events were defined based on the first positive laboratory final identification of CD after day 3 of hospitalization, accompanied by use of a CD drug. The generalized linear model method via negative binomial regression was used to identify predictors. Standardized infection ratios (SIRs) were calculated based on 2 risk-adjusted models: a simple model using descriptive variables and a complex model using descriptive variables and CD testing practices. The performance of each model was compared against cHT-CDI unadjusted rates.

RESULTS

The median rate of cHT-CDI events per 100 admissions was 0.134 (interquartile range, 0.023-0.243). Hospital variables associated with cHT-CDI included the following: higher community-onset CDI (CO-CDI) prevalence; highest-quartile length of stay; bed size; percentage of male patients; teaching hospitals; increased CD testing intensity; and CD testing prevalence. The complex model demonstrated better model performance and identified the most influential predictors: hospital-onset testing intensity and prevalence, CO-CDI rate, and community-onset testing intensity (negative correlation). Moreover, 78% of the hospitals ranked in the highest quartile based on raw rate shifted to lower percentiles when we applied the SIR from the complex model.

CONCLUSIONS

Hospital descriptors, aggregate patient characteristics, CO-CDI burden, and clinical testing practices significantly influence incidence of cHT-CDI. Benchmarking a cHT-CDI metric is feasible and should include facility and clinical variables.

Oral teicoplanin administration suppresses recurrence of Clostridioides difficile infection: Proof of concept

OBJECTIVES

Teicoplanin is a potential antimicrobial candidate for Clostridioides difficile infection (CDI) treatment. However, the therapeutic potential of teicoplanin against severe CDI has not been clinically proven. In the present study, we investigated the efficacy of oral teicoplanin administration against severe CDI and the recurrence of severe CDI after teicoplanin treatment in a mouse model.

METHODS

A lethal CDI mouse model was established by colonizing the mice with C. difficile ATCC® 43255; they were orally administered teicoplanin (128 mg/kg/d) or vancomycin (160 mg/kg/d) for 10 d, 24 h after C. difficile spore challenge, and physiological and biological responses were monitored for 20 d after the initial antibiotic treatment. We also performed the in vitro time-kill assay and determined minimum inhibitory concentration (MIC), post-antibiotic effect, and toxin production with antibiotic exposure.

RESULTS

The therapeutic response (survival rates, body weight change, clinical sickness score grading, C. difficile load, and toxin titer in feces) of oral teicoplanin administration was comparable to that of oral vancomycin administration in the lethal CDI mouse model. Moreover, teicoplanin treatment suppressed the re-onset of diarrhea and re-increase in toxin titer 10 d after treatment compared with that by vancomycin treatment. In in vitro experiments, teicoplanin exhibited time-dependent antibacterial activity and possessed lower MIC and longer post-antibiotic effect than vancomycin against C. difficile. C. difficile toxin production was numerically lower with teicoplanin exposure than with vancomycin exposure.

CONCLUSIONS

The results obtained from the present basic experiments could suggest that teicoplanin is a potential antibiotic for the treatment of severe CDI with recurrence-prevention activity.

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.

Clostridioides difficile infection leading to fulminant colitis with toxic megacolon

Clostridioidesdifficile infection (CDI) is the culprit of millions of nosocomial infections in the United States. Programs that successfully decrease its incidence, therefore, render cost savings for the healthcare system. Toxic megacolon and perforation are two of the most significant complications with increased mortality rates. We report a 23-year-old nursing home resident hospitalized for fever, cough, and green sputum. After 3 days of antibiotic therapy, he developed abdominal distension, diarrhea, and vomiting and underwent a total colectomy. The colon was dilated to a maximum of 11 cm with markedly edematous mucosa and yellow pseudomembranes. Qualitative PCR of the stool detected Clostridioides difficile toxin B gene. While there is no consensus for the required interval between antibiotic treatment and CDI, this presentation 3 days after starting the antibiotic therapy is earlier than most proposed ranges.

Central in vivo mechanisms by which C. difficile's proline reductase drives efficient metabolism, growth, and toxin production

Clostridioides difficile (CD) is a sporulating and toxin-producing nosocomial pathogen that opportunistically infects the gut, particularly in patients with depleted microbiota after antibiotic exposure. Metabolically, CD rapidly generates energy and substrates for growth from Stickland fermentations of amino acids, with proline being a preferred reductive substrate. To investigate the in vivo effects of reductive proline metabolism on C. difficile's virulence in an enriched gut nutrient environment, we evaluated wild-type and isogenic ΔprdB strains of ATCC43255 on pathogen behaviors and host outcomes in highly susceptible gnotobiotic mice. Mice infected with the ΔprdB mutant demonstrated extended survival via delayed colonization, growth and toxin production but ultimately succumbed to disease. In vivo transcriptomic analyses demonstrated how the absence of proline reductase activity more broadly disrupted the pathogen's metabolism including failure to recruit oxidative Stickland pathways, ornithine transformations to alanine, and additional pathways generating growth-promoting substrates, contributing to delayed growth, sporulation, and toxin production. Our findings illustrate the central role for proline reductase metabolism to support early stages of C. difficile colonization and subsequent impact on the pathogen's ability to rapidly expand and cause disease.

Clostridioides difficile Infection in COVID-19 Hospitalized Patients: A Nationwide Analysis

Background

Clostridioides difficile infection (CDI) is a significant healthcare-associated infection with implications for patient morbidity, mortality, and healthcare costs. However, the connection between CDI and coronavirus disease 2019 (COVID-19) infection and its influence on patient outcomes remain uncertain. This study aimed to examine the association between CDI and COVID-19, specifically investigating whether CDI worsens outcomes in patients with COVID-19. By utilizing the extensive National Inpatient Sample (NIS) database and analyzing pertinent factors, this research endeavored to enhance our understanding of CDI within the context of COVID-19.

Methods

The NIS database was searched for adult patients hospitalized with a primary diagnosis of COVID-19 infection in 2020. Patients with a secondary diagnosis of CDI were identified and separated into two groups based on CDI status. Baseline characteristics, Charlson Comorbidity Index (CCI), and outcomes were compared between the two groups using Chi-square and t-tests. Multivariate logistic and linear regressions were performed for the identification of independent predictors of CDI and mortality.

Results

A total of 1,045,125 COVID-19 hospitalizations were included, of which 4,920 had a secondary diagnosis of CDI. Patients with CDI and COVID-19 were older (mean age 69.9 vs. 64.2 years; P < 0.001), more likely to be female (54.1% vs. 47.1%; P < 0.001) and white (60% vs. 52.4%; P < 0.001). The CDI and COVID-19 group had a longer length of stay (14.1 vs. 7.42 days; P < 0.001), higher total hospital costs ($42,336 vs. $18,974; P < 0.001), and higher inpatient mortality (21.6% vs. 11%; P < 0.001) compared to the COVID-19 group without CDI. Patients in the CDI and COVID-19 group had a higher CCI score (51.7% with a score of 3 or more vs. 27.7%; P < 0.001), indicating a higher comorbidity burden. Multivariate logistic regression analysis revealed CDI was independently associated with increased mortality (odds ratio (OR) 1.37; P = 0.001) and showed that the female gender and several pre-existing comorbidities were associated with a higher likelihood of CDI.

Conclusion

CDI is independently associated with increased mortality in patients admitted with COVID-19 infection. Female gender and several pre-existing comorbidities are independent predictors of CDI in COVID-19 patients.

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.

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

Background

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

Objectives

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

Design

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

Methods

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

Results

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

Conclusion

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

Clostridioides difficile Infection: Landscape and Microbiome Therapeutics

Clostridioides difficile infection (CDI) is the leading cause of hospital-acquired diarrhea and is common in the community. Both younger individuals who may be healthy otherwise and older individuals with comorbid conditions are at risk for developing CDI, with the predominant risk factor being antibiotic use. Unlike other gastrointestinal infections, CDI is not self-limited, requires antimicrobial therapy, and tends to recur at high rates even without additional risk factor exposure. The goals of CDI management include controlling active symptoms and using a recurrence prevention strategy such as a narrow-spectrum antibiotic, tapered and pulsed regimens, antibody- based therapies (directed against toxin B), or microbiome restoration. In recent years, fecal microbiota transplantation (FMT) has been the most used modality to prevent recurrent CDI with high cure rates. Heterogeneity, lack of scalability, and serious adverse events from FMT have led to development of standardized microbiota restoration therapies (MRTs). The US Food and Drug Administration has approved 2 stool-derived MRTs for prevention of recurrent CDI: fecal microbiota, live-jslm, an enema-based therapy; and fecal microbiota spores, live-brpk, an oral therapy. A phase 3 trial for a synthetic oral MRT is underway. This article outlines the pathophysiology and treatment of CDI, focusing primarily on the gut microbiome and standardized MRTs.

Budget Impact Analysis of Adopting a One-Step Nucleic Acid Amplification Testing (NAAT) Alone Diagnostic Pathway for Clostridioides difficile in Japan Compared to a Two-Step Algorithm with Glutamate Dehydrogenase/Toxin Followed by NAAT

Clostridioides difficile infection (CDI) is a major healthcare-associated infection that leads to a significant health economic burden in Japan. Using a decision tree model, we evaluated the budget impact of adopting a one-step nucleic acid amplification test (NAAT) alone pathway compared to a two-step diagnostic algorithm with glutamate dehydrogenase (GDH) and toxin antigen, followed by NAAT. The analysis was conducted from the government payer's perspective for 100,000 symptomatic, hospitalized adults requiring a CDI diagnostic test. One-way sensitivity analysis was conducted for all data inputs. The NAAT alone strategy costed JPY 225,886,360 (USD 2,424,714) more, but was more effective, resulting in 1749 more patients accurately diagnosed and 91 fewer deaths compared to the two-step algorithm. Additionally, the NAAT alone pathway costed JPY 26,146 (USD 281) less per true positive CDI diagnosed. The total budget impact, and cost per CDI diagnosed was most sensitive to GDH sensitivity in one-way sensitivity analysis, where a lower GDH sensitivity resulted in greater cost savings with the NAAT alone pathway. Findings from this budget impact analysis can guide the adoption of a NAAT alone pathway for CDI diagnosis in Japan.

Dry alginate beads for fecal microbiota transplantation: from model strains to fecal samples

Clostridioides difficile infection (CDI) is a critical nosocomial infection with more than 124,000 cases per year in Europe and a mortality rate of 15-17%. The standard of care (SoC) is antibiotic treatment. Unfortunately, the relapse rate is high (∼35%) and SoC is significantly less effective against recurrent infection (rCDI). Fecal microbiota transplantation (FMT) is a recommended treatment against rCDI from the second recurrence episode and has an efficacy of 90%. The formulation of diluted donor stool deserves innovation because its actual administration routes deserve optimization (naso-duodenal/jejunal tubes, colonoscopy, enema or several voluminous oral capsules). Encapsulation of model bacteria strains in gel beads were first investigated. Then, the encapsulation method was applied to diluted stools. Robust spherical gel beads were obtained. The mean particle size was around 2 mm. A high loading of viable microorganisms was obtained for model strains and fecal samples. For plate-counting, values ranged from 10¹⁵ to 10¹⁷ CFU/g for single and mixed model strains, and 10⁶ to 10⁸ CFU/g for fecal samples. This corresponded to a viability of 30% to 60% as assessed by flow cytometry. This novel formulation is promising as the technology is applicable to both model strains and bacteria contained in the gut microbiota.

Final Results from a Phase 2b Randomized, Placebo-Controlled Clinical Trial of RBX2660: A Microbiota-Based Drug for the Prevention of Recurrent Clostridioides difficile Infection

INTRODUCTION

Effective treatments for recurrent Clostridioides difficile infection (rCDI) are urgently needed. RBX2660 is an investigational microbiota-based live biotherapeutic to reduce CDI recurrence following standard-of-care antibiotic treatment in individuals with rCDI. Here we report the final safety data through 24 months of follow-up as well as final efficacy data, reflecting alignment of the pre-specified statistical analysis plan definitions with the data presented.

METHODS

The PUNCH CD2 clinical trial was a prospective, multicenter, randomized, double-blinded, placebo-controlled, three-arm phase 2b study conducted to evaluate the efficacy and safety of RBX2660 for the reduction of rCDI compared to placebo. Eligible patients were at least 18 years of age and had at least three episodes of CDI and at least two rounds of standard antibiotic treatment or had at least two episodes of severe CDI resulting in hospitalization. Patients were randomized 1:1:1 to group A, two doses of RBX2660; group B, two doses of placebo; or group C, one dose of RBX2660 and one dose of placebo; all administered 7 ± 2 days apart. Treatment success was prevention of recurrence, defined as absence of diarrhea and no re-treatment for CDI any time after the first dose until 8 weeks after the second dose of the study treatment. Safety was assessed by reports of adverse events and symptoms. The final efficacy and safety are reported for data available through 24 months.

RESULTS

For the primary endpoint, treatment success at 8 weeks, 56.8% (25/45) of participants who received one dose of RBX2660 + one dose of placebo, 55.6% (25/45) of participants who received two doses of RBX2660, and 43.2% (19/44) of participants who received two doses of placebo in the final intention-to-treat (ITT) population were responders (both p = 0.2 vs placebo). In the per-protocol population, 87.5% (21/24) of participants who received one dose of RBX2660 + one dose of placebo and 58.1% (18/31) of those who received two doses of placebo had treatment success (p = 0.017; treatment difference, 29.4 [95% CI 7.6, 51.3]); 75.0% (21/28) of participants in the PP population who received two doses of RBX2660 were responders (p = 0.17 vs placebo). The safety profile of RBX2660, whether delivered as one or two doses, was similar to the placebo group.

CONCLUSION

While the phase 2b PUNCH CD2 clinical trial did not meet its pre-defined primary endpoint of treatment success at 8 weeks after two doses of RBX2660 vs two doses of placebo, clinically meaningful data were obtained to justify proceeding with the single dose regimen in the phase 3 clinical trial, PUNCH CD3, now complete. To date, the cumulative data for RBX2660 demonstrate consistent efficacy and safety outcomes for reduction of CDI recurrence in adults.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT02299570.

The Urgent Threat of Clostridioides difficile Infection: A Glimpse of the Drugs of the Future, with Related Patents and Prospects

Clostridioides difficile infection (CDI) is an urgent threat and unmet medical need. The current treatments for CDI are not enough to fight the burden of CDI and recurrent CDI (r-CDI). This review aims to highlight the future drugs for CDI and their related patented applications. The non-patent literature was collected from PubMed and various authentic websites of pharmaceutical industries. The patent literature was collected from free patent databases. Many possible drugs of the future for CDI, with diverse mechanisms of action, are in development in the form of microbiota-modulating agents (e.g., ADS024, CP101, RBX2660, RBX7455, SYN-004, SER-109, VE303, DAV132, MET-2, and BB128), small molecules (e.g., ridinilazole, ibezapolstat, CRS3123, DNV3837, MGB-BP-3, alanyl-L-glutamine, and TNP-2198), antibodies (e.g., IM-01 and LMN-201), and non-toxic strains of CD (e.g., NTCD-M3). The development of some therapeutic agents (e.g., DS-2969b, OPS-2071, cadazolid, misoprostol, ramoplanin, KB109, LFF571, and Ramizol) stopped due to failed clinical trials or unknown reasons. The patent literature reveals some important inventions for the existing treatments of CDI and supports the possibility of developing more and better CDI-treatment-based inventions, including patient-compliant dosage forms, targeted drug delivery, drug combinations of anti-CDI drugs possessing diverse mechanisms of action, probiotic and enzymatic supplements, and vaccines. The current pipeline of anti-CDI medications appears promising. However, it will be fascinating to see how many of the cited are successful in gaining approval from drug regulators such as the US FDA and becoming medicines for CDI and r-CDI.

Clostridioides difficile infection in mechanically ventilated critically ill patients: A nested cohort study

INTRODUCTION

Clostridioides difficile infection (CDI) is a serious complication of critical illness. The objective of the study was to determine its incidence, prevalence, timing, severity, predictors, and outcomes.

METHODS

We performed a prospective nested cohort study of CDI within a randomized trial comparing Lactobacillus rhamnosus GG to placebo. We adjudicated cases of CDI using standardized definitions, assessed timing (pre-ICU, in ICU, post-ICU) and severity. We analyzed risk factors and outcomes.

RESULTS

Of 2650 patients, 86 were diagnosed with CDI during 90,833 hospital-days (0.95/1000 hospital-days); CDI prevalence was 3.2%. CDI incidence varied in timing; 0.3% patients had CDI pre-ICU, 2.2% in the ICU; an 0.8% developed CDI post-ICU. Relapse or recurrence of CDI was documented in 9.3% patients. Infections were mild/moderate in severity. Complications included septic shock (26.7%), organ failure (16.3%), and toxic megacolon requiring colectomy (1.2%). No risk factors for CDI were identified. CDI was not associated with hospital mortality. The duration of hospital stay was longer for those who had CDI compared those who did not, CONCLUSION: CDI was uncommon, severity was mild to moderate and not associated with mortality however CDI was associated with a longer hospital stay.

Adenosine receptors differentially mediate enteric glial cell death induced by Clostridioides difficile Toxins A and B

Increased risk of intestinal dysfunction has been reported in patients after Clostridioides difficile infection (CDI). Enteric glial cells (EGCs), a component of the enteric nervous system (ENS), contribute to gut homeostasis. Previous studies showed that adenosine receptors, A2A and A2B, modulate inflammation during CDI. However, it is unknown how these receptors can modulate the EGC response to the C. difficile toxins (TcdA and TcdB). We investigated the effects of these toxins on the expression of adenosine receptors in EGCs and the role of these receptors on toxin-induced EGC death. Rat EGCs line were incubated with TcdA or TcdB alone or in combination with adenosine analogues 1h prior to toxins challenge. After incubation, EGCs were collected to evaluate gene expression (adenosine receptors and proinflammatory markers) and cell death. In vivo, WT, A2A, and A2B KO mice were infected with C. difficile, euthanized on day 3 post-infection, and cecum tissue was processed. TcdA and TcdB increased A2A and A3 transcripts, as well as decreased A2B. A2A agonist, but not A2A antagonist, decreased apoptosis induced by TcdA and TcdB in EGCs. A2B blocker, but not A2B agonist, diminished apoptosis in EGCs challenged with both toxins. A3 agonist, but not A3 blocker, reduced apoptosis in EGCs challenged with TcdA and TcdB. Inhibition of protein kinase A (PKA) and CREB, both involved in the main signaling pathway driven by activation of adenosine receptors, decreased EGC apoptosis induced by both toxins. A2A agonist and A2B antagonist decreased S100B upregulation induced by C. difficile toxins in EGCs. In vivo, infected A2B KO mice, but not A2A, exhibited a decrease in cell death, including EGCs and enteric neuron loss, compared to infected WT mice, reduced intestinal damage and decreased IL-6 and S100B levels in cecum. Our findings indicate that upregulation of A2A and A3 and downregulation of A2B in EGCs and downregulation of A2B in intestinal tissues elicit a protective response against C. difficile toxins. Adenosine receptors appear to play a regulatory role in EGCs death and proinflammatory response induced by TcdA and TcdB, and thus may be potential targets of intervention to prevent post-CDI intestinal dysmotility.

Improving care for patients with Clostridioides difficile infection: A clinical practice and healthcare systems perspective

Introduction

Arriving at a C. difficile infection (CDI) diagnosis, treating patients and dealing with recurrences is not straightforward, but a comprehensive and well-rounded understanding of what is needed to improve patient care is lacking. This manuscript addresses the paucity of multidisciplinary perspectives that consider clinical practice related and healthcare system-related challenges to optimizing care delivery.

Methods

We draw on narrative review, consultations with clinical experts and patient representatives, and a survey of 95 clinical and microbiology experts from the UK, France, Italy, Australia and Canada, adding novel multi-method evidence to the knowledge base.

Results and discussion

We examine the patient pathway and variations in clinical practice and identify, synthesize insights on and discuss associated challenges. Examples of key challenges include the need to conduct multiple tests for a conclusive diagnosis, treatment side-effects, the cost of some antibiotics and barriers to access of fecal microbiota transplantation, difficulties in distinguishing recurrence from new infection, workforce capacity constraints to effective monitoring of patients on treatment and of recurrence, and ascertaining whether a patient has been cured. We also identify key opportunities and priorities for improving patient care that target both clinical practice and the wider healthcare system. While there is some variety across surveyed countries' healthcare systems, there is also strong agreement on some priorities. Key improvement actions seen as priorities by at least half of survey respondents in at least three of the five surveyed countries include: developing innovative products for both preventing (Canada, Australia, UK, Italy, and France) and treating (Canada, Australia, and Italy) recurrences; facilitating more multidisciplinary patient care (UK, Australia, and France); updating diagnosis and treatment guidelines (Australia, Canada, and UK); and educating and supporting professionals in primary care (Italy, UK, Canada, and Australia) and those in secondary care who are not CDI experts (Italy, Australia, and France) on identifying symptoms and managing patients. Finally, we discuss key evidence gaps for a future research agenda.

Clinical and Economic Outcomes After Implementation of a Fidaxomicin Treatment Optimization and Access Pathway at a US Hospital System

INTRODUCTION

This study aimed to evaluate the clinical and economic outcomes of implementing a Clostridiodes difficile infection (CDI) Treatment Optimization and Access Pathway (treatment pathway) directing first-line use of fidaxomicin for CDI.

METHODS

This was a retrospective, quasi-experimental study of adult patients with CDI using Electronic Health Record data from a single center. The primary intervention was implementation of a treatment pathway directing first-line use of fidaxomicin for patients with first/second CDI episode and at high risk of recurrence. The primary clinical outcome was CDI recurrence within 30 days of completing therapy in patients achieving clinical cure. Secondary clinical outcomes included clinical cure and sustained response evaluated at 90 days after completion of CDI treatment. Economic outcomes included costs associated with hospital stay at index admission and 30- and 90-day readmission. Differences between the pre- and post-implementation cohorts were assessed for baseline characteristics, CDI treatment utilization, clinical outcomes, and economic outcomes. The budget impact was calculated for the pre- vs. post-implementation cohorts, each normalized to 100 patients.

RESULTS

Post- vs. pre-implementation, 30-day recurrence (6.4% vs. 18.0%., p = 0.001), 90-day recurrence (14.9% vs. 27.1%, p = 0.009), and 30-day (4.6% vs. 12.7%, p = 0.007) and 90-day CDI-related readmissions (8.5% vs. 18.9%, p = 0.007) were lower. The clinical cure (94.1% vs. 84.4%, p = 0.002) and 90-day sustained response rates were higher (73.3% vs. 55.9%, p < 0.001). Median total costs were also lower in the post- vs. pre-implementation cohorts at index admission ($11,934.64 vs. $14,523.27, p = 0.048), and 30-day ($7685.82 vs. $12,424.44, p = 0.102) and 90-day CDI-related readmission episodes ($8246.69 vs. $12,729.57, p = 0.042). The budget impact analyses of 100 patients post- vs. pre-implementation found saving of $222,895 overall and $9432 per CDI-readmission avoided.

CONCLUSIONS

Implementation of the CDI treatment pathway was associated with better clinical outcomes and hospital cost savings. The findings help validate real-world value of fidaxomicin for CDI disease management.

Application of recombinant antibodies for treatment of Clostridioides difficile infection: Current status and future perspective

Clostridioides difficile (C. difficile), known as the major cause of antibiotic-associated diarrhea, is regarded as one of the most common healthcare-associated bacterial infections worldwide. Due to the emergence of hypervirulent strains, development of new therapeutic methods for C. difficile infection (CDI) has become crucially important. In this context, antibodies have been introduced as valuable tools in the research and clinical environments, as far as the effectiveness of antibody therapy for CDI was reported in several clinical investigations. Hence, production of high-performance antibodies for treatment of CDI would be precious. Traditional approaches of antibody generation are based on hybridoma technology. Today, application of in vitro technologies for generating recombinant antibodies, like phage display, is considered as an appropriate alternative to hybridoma technology. These techniques can circumvent the limitations of the immune system and they can be exploited for production of antibodies against different types of biomolecules in particular active toxins. Additionally, DNA encoding antibodies is directly accessible in in vitro technologies, which enables the application of antibody engineering in order to increase their sensitivity and specificity. Here, we review the application of antibodies for CDI treatment with an emphasis on recombinant fragment antibodies. Also, this review highlights the current and future prospects of the aforementioned approaches for antibody-mediated therapy of CDI.

Oral fidaxomicin versus vancomycin for the treatment of Clostridioides difficile infection: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Fidaxomicin (FDX) has received considerable attention as a novel therapeutic alternative agent to vancomycin (VCM) for Clostridioides difficile infection (CDI). However, the superiority and efficacy profile of FDX are not sufficiently determined by high-quality evidence. This study aimed to clarify the superiority of FDX for CDI treatment through a systematic review and meta-analysis.

METHODS

We conducted a meta-analysis of randomized controlled trials (RCTs) which evaluated the efficacy and safety of FDX and VCM in patients with CDI. Electronic databases (PubMed, Cochrane Library, Web of Science, and Clinicaltrials.gov) were searched for studies published until October 15, 2021. The primary endpoint was global cure. The secondary endpoints were clinical cure, recurrence, and adverse event. Risk ratios (RRs), risk differences (RDs), and 95% confidence intervals were calculated using Mantel-Haenszel random-effects model. The risk of bias was assessed using Cochrane Handbook for Systematic Reviews of Interventions and Assessment Criteria.

RESULTS

Six RCTs were included in this meta-analysis. Compared to VCM, FDX was associated with significantly higher global cure rates (RR = 1.18, P < 0.00001; RD = 0.11, 95% CI = 0.07-0.16). In addition, clinical cure rates were comparable between FDX and VCM (P = 0.31). FDX was associated with significantly lower recurrence rates compared to VCM (RR = 0.59, P < 0.0001). In addition, adverse event rates were not significantly different between the drugs (P = 0.41).

CONCLUSION

FDX achieves significantly higher global cure rates and lower recurrence rates and is comparable to VCM in clinical cure rates and adverse event rates in patients with CDI. Collectively, FDX is superior to VCM as a therapeutic agent for CDI.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

The Risk of Clostridioides difficile Recurrence after Initial Treatment with Vancomycin or Fidaxomicin Utilizing Cerner Health Facts

(1) Background: Fidaxomicin has been shown to significantly reduce Clostridioides difficile infection (CDI) recurrences rates in randomized, controlled trials. However, national data from the Veterans Affairs has called the real-world applicability of these findings into question. Therefore, we conducted a retrospective cohort study of patients receiving fidaxomicin or vancomycin as initial therapy for an index case of CDI in the hospital to evaluate the relative rates CDI recurrence within 90 days of an index case. (2) Methods: We retrieved patients 18 years and older who were admitted between July 2011 through June 2018 and diagnosed and treated for CDI with vancomycin or fidaxomicin. The first occurrence of CDI with treatment was designated as the index case. Patients with CDI within 1 year prior to index case were excluded. From the remaining index cases (vancomycin = 14,785; fidaxomicin = 889) the primary outcome (a recurrence of CDI within 90 days of the index case) was determined. The CDI recurrence rates for fidaxomicin and vancomyicn were evaluated using a Cox Proportional Hazards model on a propensity score matched cohort. (3) Results: A statistically significantly lower risk of CDI recurrence was observed with fidaxomicin use in the matched cohort (889 patients per treatment) using a Cox Proportional Hazards model (HR 0.67, 95% CI 0.50–0.90). (4) Conclusions: Fidaxomicin was independently associated with a decreased CDI recurrence, as defined by readmission for CDI within 90 days.

Mycobacterium tuberculosis DNA repair helicase UvrD1 is activated by redox-dependent dimerization via a 2B domain cysteine

Mycobacterium tuberculosis (Mtb) causes tuberculosis and, during infection, is exposed to reactive oxygen species and reactive nitrogen intermediates from the host immune response that can cause DNA damage. UvrD-like proteins are involved in DNA repair and replication and belong to the SF1 family of DNA helicases that use ATP hydrolysis to catalyze DNA unwinding. In Mtb, there are two UvrD-like enzymes, where UvrD1 is most closely related to other family members. Previous studies have suggested that UvrD1 is exclusively monomeric; however, it is well known that Escherichia coli UvrD and other UvrD family members exhibit monomer-dimer equilibria and unwind as dimers in the absence of accessory factors. Here, we reconcile these incongruent studies by showing that Mtb UvrD1 exists in monomer, dimer, and higher-order oligomeric forms, where dimerization is regulated by redox potential. We identify a 2B domain cysteine, conserved in many Actinobacteria, that underlies this effect. We also show that UvrD1 DNA-unwinding activity correlates specifically with the dimer population and is thus titrated directly via increasing positive (i.e., oxidative) redox potential. Consistent with the regulatory role of the 2B domain and the dimerization-based activation of DNA unwinding in UvrD family helicases, these results suggest that UvrD1 is activated under oxidizing conditions when it may be needed to respond to DNA damage during infection.

Regulation of Clostridioides difficile toxin production

Clostridioides difficile produces toxins TcdA and TcdB during infection. Since the severity of the illness is directly correlated with the level of toxins produced, researchers have long been interested in the regulation mechanisms of toxin production. The advent of new genetics and mutagenesis technologies in C. difficile has allowed a slew of new investigations in the last decade, which considerably improved our understanding of this crucial regulatory network. The current body of work shows that the toxin regulatory network overlaps with the regulatory networks of sporulation, motility, and key metabolic pathways. This implies that toxin production is a complicated process initiated by bacteria in response to numerous host factors during infection. We summarize the existing knowledge about the toxin gene regulatory network here.

Efficacy and Safety of Faecal Microbiota Transplantation for Acute Pancreatitis: A Randomised, Controlled Study

Aims: We investigated whether faecal microbiota transplantation (FMT) decreases intra-abdominal pressure (IAP) and improves gastrointestinal (GI) dysfunction and infectious complications in acute pancreatitis (AP). Methods: In this first randomised, single-blind, parallel-group, controlled study, we recruited and enrolled consecutive patients with AP complicated with GI dysfunction. Eligible participants were randomly assigned to receive faecal transplant (n = 30) or normal saline (n = 30) via a nasoduodenal tube once and then again 2 days later. The primary endpoint was the rate of IAP decline; secondary endpoints were GI function, infectious complications, organ failure, hospital stay and mortality. Analyses were based on intention to treat. Results: We enrolled 60 participants and randomly assigned them to the FMT (n = 30) or control (n = 30) group. Baseline characteristics and disease severity were similar for both groups. IAP decreased significantly 1 week after intervention in both groups, with no difference in the IAP decline rate between FMT and Control group [0.1 (-0.6, 0.5) vs. 0.2 (-0.2, 0.6); P = 0.27]. Normal gastrointestinal failure (GIF) scores were achieved in 12 (40%) patients in the FMT group and 14 (47%) in the control group, with no significant difference (P = 0.60). However, D-lactate was significantly elevated in the FMT group compared to the control group, as calculated by the rate of decline [-0.3 (-3.7, 0.8) vs. 0.4 (-1.1, 0.9); P = 0.01]. Infectious complications occurred in 15 (50%) and 16 (53.33%) patients in the FMT and control groups, respectively (P = 0.80). However, interleukin-6 (IL-6) was significantly elevated in the FMT group compared to the control group, as calculated by the rate of decline [0.4 (-3.6, 0.9) vs. 0.8 (-1.7, 1.0); P = 0.03]. One participant experienced transient nausea immediately after FMT, but no serious adverse events were attributed to FMT. Conclusion: FMT had no obvious effect on IAP and infectious complications in AP patients, though GI barrier indictors might be adversely affected. Further multi-centre studies are needed to confirm our findings. The study was registered at https://clinicaltrials.gov (NCT02318134).