Sauver JL, Harmsen WS, Zinsmeister AR. The epidemiology of community-acquired Clostridium difficile infection: a population-based study

OBJECTIVES

Clostridium difficile infection (CDI) is a common hospital-acquired infection with increasing incidence, severity, recurrence, and associated morbidity and mortality. There are emerging data on the occurrence of CDI in nonhospitalized patients. However, there is a relative lack of community-based CDI studies, as most of the existing studies are hospital based, potentially influencing the results by referral or hospitalization bias by missing cases of community-acquired CDI.

METHODS

To better understand the epidemiology of community-acquired C. difficile infection, a population-based study was conducted in Olmsted County, Minnesota, using the resources of the Rochester Epidemiology Project. Data regarding severity, treatment response, and outcomes were compared in community-acquired vs. hospital-acquired cohorts, and changes in these parameters, as well as in incidence, were assessed over the study period.

RESULTS

Community-acquired CDI cases accounted for 41% of 385 definite CDI cases. The incidence of both community-acquired and hospital-acquired CDI increased significantly over the study period. Compared with those with hospital-acquired infection, patients with community-acquired infection were younger (median age 50 years compared with 72 years), more likely to be female (76% vs. 60%), had lower comorbidity scores, and were less likely to have severe infection (20% vs. 31%) or have been exposed to antibiotics (78% vs. 94%). There were no differences in the rates of complicated or recurrent infection in patients with community-acquired compared with hospital-acquired infection.

CONCLUSIONS

In this population-based cohort, a significant proportion of cases of CDI occurred in the community. These patients were younger and had less severe infection than those with hospital-acquired infection. Thus, reports of CDI in hospitalized patients likely underestimate the burden of disease and overestimate severity.

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

BACKGROUND

Patients with recurrent Clostridium difficile infection (CDI) have a ≥60% risk of relapse, as conventional therapies do not address the underlying gastrointestinal dysbiosis. This exploratory study evaluated the safety and efficacy of bacterial spores for preventing recurrent CDI.

METHODS

Stool specimens from healthy donors were treated with ethanol to eliminate pathogens. The resulting spores were fractionated and encapsulated for oral delivery as SER-109. Following their response to standard-of-care antibiotics, patients in cohort 1 were treated with SER-109 on 2 consecutive days (geometric mean dose, 1.7 × 10(9) spores), and those in cohort 2 were treated on 1 day (geometric mean dose, 1.1 × 10(8) spores). The primary efficacy end point was absence of C. difficile-positive diarrhea during an 8-week follow-up period. Microbiome alterations were assessed.

RESULTS

Thirty patients (median age, 66.5 years; 67% female) were enrolled, and 26 (86.7%) met the primary efficacy end point. Three patients with early, self-limiting C. difficile-positive diarrhea did not require antibiotics and tested negative for C. difficile at 8 weeks; thus, 96.7% (29 of 30) achieved clinical resolution. In parallel, gut microbiota rapidly diversified, with durable engraftment of spores and no outgrowth of non-spore-forming bacteria found after SER-109 treatment. Adverse events included mild diarrhea, abdominal pain, and nausea.

CONCLUSIONS

SER-109 successfully prevented CDI and had a favorable safety profile, supporting a novel microbiome-based intervention as a potential therapy for recurrent CDI.

Systematic review: colitis associated with anti-CTLA-4 therapy

BACKGROUND

Cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) has an important role in T-cell regulation, proliferation and tolerance. Anti-CTLA-4 agents, such as ipilimumab and tremelimumab, have been shown to prolong overall survival in patients with metastatic melanoma, and their use is being investigated in the treatment of other malignancies. Their novel immunostimulatory mechanism, however, predisposes patients to immune-related adverse effects, of which gastrointestinal effects such as diarrhoea and colitis are the most common.

AIMS

To discuss the existing literature and summarise the epidemiology, pathogenesis and clinical features of anti-CTLA-4-associated colitis, and to present a management algorithm for it.

METHODS

We searched PubMed for studies published through October 2014 using the terms 'anti-CTLA,' 'ipilimumab,' 'tremelimumab,' 'colitis,' 'gastrointestinal,' 'immune-related adverse effect,' 'immunotherapy,' 'melanoma,' and 'diarrhoea.'

RESULTS

Watery diarrhoea is commonly associated with anti-CTLA-4 therapy (27-54%), and symptoms occur within a few days to weeks of therapy. Diffuse acute and chronic colitis are the most common findings on endoscopy (8-22%). Concomitant infectious causes of diarrhoea must be evaluated. Most cases may be successfully managed with discontinuation of anti-CTLA-4 and conservative therapy. Those with persistent grade 2 and grade 3/4 diarrhoea should undergo endoscopic evaluation and require corticosteroid therapy. Corticosteroid-resistant cases may respond to anti-tumour necrosis factor-alpha therapy such as infliximab. Surgery is reserved for patients with bowel perforation or failure of medical therapy.

CONCLUSION

Given the increasing use of anti-CTLA-4 therapy, clinicians must be aware of related adverse events and their management.

The epidemiology of Clostridium difficile infection in children: a population-based study

BACKGROUND

The incidence of Clostridium difficile infection (CDI) is increasing, even in populations previously thought to be at low risk, including children. Most incidence studies have included only hospitalized patients and are thus potentially influenced by referral or hospitalization biases.

METHODS

We performed a population-based study of CDI in pediatric residents (aged 0-18 years) of Olmsted County, Minnesota, from 1991 through 2009 to assess the incidence, severity, treatment response, and outcomes of CDI.

RESULTS

We identified 92 patients with CDI, with a median age of 2.3 years (range, 1 month-17.6 years). The majority of cases (75%) were community-acquired. The overall age- and sex-adjusted CDI incidence was 13.8 per 100 000 persons, which increased 12.5-fold, from 2.6 (1991-1997) to 32.6 per 100 000 (2004-2009), over the study period (P < .0001). The incidence of community-acquired CDI was 10.3 per 100 000 persons and increased 10.5-fold, from 2.2 (1991-1997) to 23.4 per 100 000 (2004-2009) (P < .0001). Severe, severe-complicated, and recurrent CDI occurred in 9%, 3%, and 20% of patients, respectively. The initial treatment in 82% of patients was metronidazole, and 18% experienced treatment failure. In contrast, the initial treatment in 8% of patients was vancomycin and none of them failed therapy.

CONCLUSIONS

In this population-based cohort, CDI incidence in children increased significantly from 1991 through 2009. Given that the majority of cases were community-acquired, estimates of the incidence of CDI that include only hospitalized children may significantly underestimate the burden of disease in children.

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

BACKGROUND

Recurrent Clostridioides difficile infection, associated with dysbiosis of gut microbiota, has substantial disease burden in the USA. RBX2660 is a live biotherapeutic product consisting of a broad consortium of microbes prepared from human stool that is under investigation for the reduction of recurrent C. difficile infection.

METHODS

A randomized, double-blind, placebo-controlled, phase III study, with a Bayesian primary analysis integrating data from a previous phase IIb study, was conducted. Adults who had one or more C. difficile infection recurrences with a positive stool assay for C. difficile and who were previously treated with standard-of-care antibiotics were randomly assigned 2:1 to receive a subsequent blinded, single-dose enema of RBX2660 or placebo. The primary endpoint was treatment success, defined as the absence of C. difficile infection diarrhea within 8 weeks of study treatment.

RESULTS

Of the 320 patients screened, 289 were randomly assigned and 267 received blinded treatment (n = 180, RBX2660; n = 87, placebo). Original model estimates of treatment success were 70.4% versus 58.1% with RBX2660 and placebo, respectively. However, after aligning the data to improve the exchangeability and interpretability of the Bayesian analysis, the model-estimated treatment success rate was 70.6% with RBX2660 versus 57.5% with placebo, with an estimated treatment effect of 13.1% and a posterior probability of superiority of 0.991. More than 90% of the participants who achieved treatment success at 8 weeks had sustained response through 6 months in both the RBX2660 and the placebo groups. Overall, RBX2660 was well tolerated, with manageable adverse events. The incidence of treatment-emergent adverse events was higher in RBX2660 recipients compared with placebo and was mostly driven by a higher incidence of mild gastrointestinal events.

CONCLUSIONS

RBX2660 is a safe and effective treatment to reduce recurrent C. difficile infection following standard-of-care antibiotics with a sustained response through 6 months.

CLINICAL TRIAL REGISTRATION

NCT03244644; 9 August, 2017.

Regulation of dendritic cells and macrophages by an anti-apoptotic cell natural antibody that suppresses TLR responses and inhibits inflammatory arthritis

Although natural Abs (NAbs) are present from birth, little is known about what drives their selection and whether they have housekeeping functions. The prototypic T15-NAb, first identified because of its protective role in infection, is representative of a special type of NAb response that specifically recognizes and forms complexes with apoptotic cells and which promotes cell-corpse engulfment by phagocytes. We now show that this T15-NAb IgM-mediated clearance process is dependent on the recruitment of C1q and mannose-binding lectin, which have known immune modulatory activities that also provide "eat me" signals for enhancing phagocytosis. Further investigation revealed that the addition of T15-NAb significantly suppressed in vitro LPS-induced TNF-alpha and IL-6 secretion by the macrophage-like cell line, RAW264.7, as well as TLR3-, TLR4-, TLR7-, and TLR9-induced maturation and secretion of a range of proinflammatory cytokines and chemokines by bone marrow-derived conventional dendritic cells. Significantly, high doses of this B-1 cell produced NAb also suppressed in vivo TLR-induced proinflammatory responses. Although infusions of apoptotic cells also suppressed such in vivo inflammatory responses and this effect was associated with the induction of high levels of IgM antiapoptotic cell Abs, apoptotic cell treatment was not effective at suppressing such TLR responses in B cell-deficient mice. Moreover, infusions of T15-NAb also efficiently inhibited both collagen-induced arthritis and anti-collagen II Ab-mediated arthritis. These studies identify and characterize a previously unknown regulatory circuit by which a NAb product of innate-like B cells aids homeostasis by control of fundamental inflammatory pathways.

The growing incidence and severity of Clostridium difficile infection in inpatient and outpatient settings

Clostridium difficile infection (CDI) is a leading cause of nosocomial infections, with disease severity ranging from mild diarrhea to fulminant colitis. The incidence and severity of CDI has been on the rise over the last 10-20 years, with CDI being increasingly described outside healthcare settings and in populations previously thought to be at low risk. There has also been an increase in the morbidity, mortality and economic burden associated with CDI in the last several years. This increasing incidence and severity is thought to be at least partially due to frequent antibiotic use and the emergence of a hypervirulent C. difficile strain.

A clinician's primer on the role of the microbiome in human health and disease

The importance of the commensal microbiota that colonizes the skin, gut, and mucosal surfaces of the human body is being increasingly recognized through a rapidly expanding body of science studying the human microbiome. Although, at first glance, these discoveries may seem esoteric, the clinical implications of the microbiome in human health and disease are becoming clear. As such, it will soon be important for practicing clinicians to have an understanding of the basic concepts of the human microbiome and its relation to human health and disease. In this Concise Review, we provide a brief introduction to clinicians of the concepts underlying this burgeoning scientific field and briefly explore specific disease states for which the potential role of the human microbiome is becoming increasingly evident, including Clostridium difficile infection, inflammatory bowel disease, colonization with multidrug-resistant organisms, obesity, allergic diseases, autoimmune diseases, and neuropsychiatric illnesses, and we also discuss current and future roles of microbiome restorative therapies.

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

BACKGROUND

Fecal microbiota transplantation (FMT) is highly effective for treating recurrent Clostridium difficile infection (CDI) in observational studies (>90%), but cure rates in clinical trials are lower. We performed a systematic review and meta-analysis to assess the efficacy of FMT for recurrent CDI in open-label studies and clinical trials .

METHODS

A systematic search from January 1978 to March 2017 was performed to include clinical trials of FMT for CDI. We analyzed CDI resolution by calculating weighted pooled rates (WPRs).

RESULTS

Thirteen trials were included, comprising 610 patients with CDI treated with single FMT. Overall, 439 patients had clinical cure (WPR, 76.1%; 95% confidence interval (CI), 66.4%-85.7%). There was significant heterogeneity among studies (I2 = 91.35%). Cure rates were lower in randomized trials (139/216 patients; WPR, 67.7%; 95% CI, 54.2%-81.3%) than in open-label studies (300/394 patients; WPR, 82.7%; 71.1%-94.3%) (P < .001). Subgroup analysis by FMT delivery modality showed lower cure rates with enema than colonoscopy (WPR, 66.3% vs 87.4%; P < .001) but no difference between colonoscopy and oral delivery (WPR, 87.4% vs 81.4%; P = .17). Lower rates were seen for studies including both recurrent and refractory CDI than for those including only recurrent CDI (WPR, 63.9% vs 79%; P < .001).

CONCLUSIONS

FMT was associated with lower cure rates in randomized trials than in open-label and in observational studies. Colonoscopy and oral route are more effective than enema for stool delivery. The efficacy also seems to be higher for recurrent than for refractory CDI.

Fecal Microbiota Transplantation Is Highly Effective in Real-World Practice: Initial Results From the FMT National Registry

BACKGROUND & AIMS

Fecal microbiota transplantation (FMT) is used commonly for treatment of Clostridioides difficile infections (CDIs), although prospective safety data are limited and real-world FMT practice and outcomes are not well described. The FMT National Registry was designed to assess FMT methods and both safety and effectiveness outcomes from North American FMT providers.

METHODS

Patients undergoing FMT in clinical practices across North America were eligible. Participating investigators enter de-identified data into an online platform, including FMT protocol, baseline patient characteristics, CDI cure and recurrence, and short and long-term safety outcomes.

RESULTS

Of the first 259 participants enrolled at 20 sites, 222 had completed short-term follow-up at 1 month and 123 had follow-up to 6 months; 171 (66%) were female. All FMTs were done for CDI and 249 (96%) used an unknown donor (eg, stool bank). One-month cure occurred in 200 patients (90%); of these, 197 (98%) received only 1 FMT. Among 112 patients with initial cure who were followed to 6 months, 4 (4%) had CDI recurrence. Severe symptoms reported within 1-month of FMT included diarrhea (n = 5 [2%]) and abdominal pain (n = 4 [2%]); 3 patients (1%) had hospitalizations possibly related to FMT. At 6 months, new diagnoses of irritable bowel syndrome were made in 2 patients (1%) and inflammatory bowel disease in 2 patients (1%).

CONCLUSIONS

This prospective real-world study demonstrated high effectiveness of FMT for CDI with a good safety profile. Assessment of new conditions at long-term follow-up is planned as this registry grows and will be important for determining the full safety profile of FMT.

Clostridioides difficile uses amino acids associated with gut microbial dysbiosis in a subset of patients with diarrhea

The gut microbiota plays a critical role in pathogen defense. Studies using antibiotic-treated mice reveal mechanisms that increase susceptibility to Clostridioides difficile infection (CDI), but risk factors associated with CDI in humans extend beyond antibiotic use. Here, we studied the dysbiotic gut microbiota of a subset of patients with diarrhea and modeled the gut microbiota of these patients by fecal transplantation into germ-free mice. When challenged with C. difficile, the germ-free mice transplanted with fecal samples from patients with dysbiotic microbial communities showed increased gut amino acid concentrations and greater susceptibility to CDI. A C. difficile mutant that was unable to use proline as an energy source was unable to robustly infect germ-free mice transplanted with a dysbiotic or healthy human gut microbiota. Prophylactic dietary intervention using a low-proline or low-protein diet in germ-free mice colonized by a dysbiotic human gut microbiota resulted in decreased expansion of wild-type C. difficile after challenge, suggesting that amino acid availability might be important for CDI. Furthermore, a prophylactic fecal microbiota transplant in mice with dysbiosis reduced proline availability and protected the mice from CDI. Last, we identified clinical risk factors that could potentially predict gut microbial dysbiosis and thus greater susceptibility to CDI in a retrospective cohort of patients with diarrhea. Identifying at-risk individuals and reducing their susceptibility to CDI through gut microbiota-targeted therapies could be a new approach to preventing C. difficile infection in susceptible patients.

SER-109, an Investigational Microbiome Drug to Reduce Recurrence After Clostridioides difficile Infection: Lessons Learned From a Phase 2 Trial

BACKGROUND

Recurrent Clostridioides difficile infection (rCDI) is associated with loss of microbial diversity and microbe-derived secondary bile acids, which inhibit C. difficile germination and growth. SER-109, an investigational microbiome drug of donor-derived, purified spores, reduced recurrence in a dose-ranging, phase (P) 1 study in subjects with multiple rCDIs.

METHODS

In a P2 double-blind trial, subjects with clinical resolution on standard-of-care antibiotics were stratified by age (< or ≥65 years) and randomized 2:1 to single-dose SER-109 or placebo. Subjects were diagnosed at study entry by PCR or toxin testing. Safety, C. difficile-positive diarrhea through week 8, SER-109 engraftment, and bile acid changes were assessed.

RESULTS

89 subjects enrolled (67% female; 80.9% diagnosed by PCR). rCDI rates were lower in the SER-109 arm than placebo (44.1% vs 53.3%) but did not meet statistical significance. In a preplanned analysis, rates were reduced among subjects ≥65 years (45.2% vs 80%, respectively; RR, 1.77; 95% CI, 1.11-2.81), while the <65 group showed no benefit. Early engraftment of SER-109 was associated with nonrecurrence (P < .05) and increased secondary bile acid concentrations (P < .0001). Whole-metagenomic sequencing from this study and the P1 study revealed previously unappreciated dose-dependent engraftment kinetics and confirmed an association between early engraftment and nonrecurrence. Engraftment kinetics suggest that P2 dosing was suboptimal. Adverse events were generally mild to moderate in severity.

CONCLUSIONS

Early SER-109 engraftment was associated with reduced CDI recurrence and favorable safety was observed. A higher dose of SER-109 and requirements for toxin testing were implemented in the current P3 trial.

CLINICAL TRIALS REGISTRATION

NCT02437487, https://clinicaltrials.gov/ct2/show/NCT02437487?term=SER-109&draw= 2&rank=4.

Association of Gastric Acid Suppression With Recurrent Clostridium difficile Infection: A Systematic Review and Meta-analysis

IMPORTANCE

Gastric acid suppression has been associated with an increased risk of primary Clostridium difficile infection (CDI), but the risk of recurrent CDI in patients taking gastric acid suppressant medications is unclear.

OBJECTIVE

To perform a systematic review and meta-analysis to evaluate the association between gastric acid suppressants and recurrent CDI.

DATA SOURCES

MEDLINE, EMBASE, the Cochrane Central Register, the Cochrane Database, and Web of Science were searched from January 1, 1995, to September 30, 2015, for studies assessing the association between gastric acid suppressant exposure and recurrent CDI. Search terms included Clostridium difficile, pseudomembranous colitis, proton pump inhibitor, and histamine H2 blocker.

STUDY SELECTION

Case-control studies, cohort studies, and clinical trials that included patients with CDI who did or did not receive gastric acid suppressant therapy and who were evaluated for recurrent CDI were included, with no restriction on study setting (inpatient or outpatient).

DATA EXTRACTION AND SYNTHESIS

The Newcastle-Ottawa scale was used to assess the methodologic quality of included studies. In this scale, case-control and cohort studies were scored on selection, comparability, and ascertainment of the outcome of interest. Data were independently abstracted to a predetermined collection form by 2 investigators. Summary odds ratio estimates with 95% CIs were calculated using the random-effects model and software to calculate the pooled effect size of studies reporting multivariate analyses.

MAIN OUTCOMES AND MEASURES

Risk of recurrent infection in patients with CDI and its association with use of gastric acid suppressant medication.

RESULTS

Sixteen observational studies were included, together reporting 7703 patients with CDI; among these, 1525 patients (19.8%) developed recurrent CDI. The rate of recurrent CDI in patients with gastric acid suppression was 22.1% (892 of 4038 patients) compared with 17.3% (633 of 3665) in patients without gastric acid suppression, which indicated an increased risk by meta-analysis (odds ratio [OR], 1.52; 95% CI, 1.20-1.94; P < .001). There was significant heterogeneity among the studies, with an I2 value of 64%. Subgroup analyses of studies adjusting for age and potential confounders confirmed an increased risk of recurrent CDI with use of gastric acid suppressants (OR, 1.38; 95% CI, 1.08-1.76; P = .02).

CONCLUSIONS AND RELEVANCE

Meta-analyses of observational studies suggest that patients who receive gastric acid suppressants may be at increased risk for recurrent CDI. These data should be interpreted with caution because they may be confounded owing to the observational design of the individual studies. It may be reasonable to re-evaluate the need for these medications in patients with CDI.

Changes in microbial ecology after fecal microbiota transplantation for recurrent C. difficile infection affected by underlying inflammatory bowel disease

BACKGROUND

Gut microbiota play a key role in maintaining homeostasis in the human gut. Alterations in the gut microbial ecosystem predispose to Clostridium difficile infection (CDI) and gut inflammatory disorders such as inflammatory bowel disease (IBD). Fecal microbiota transplantation (FMT) from a healthy donor can restore gut microbial diversity and pathogen colonization resistance; consequently, it is now being investigated for its ability to improve inflammatory gut conditions such as IBD. In this study, we investigated changes in gut microbiota following FMT in 38 patients with CDI with or without underlying IBD.

RESULTS

There was a significant change in gut microbial composition towards the donor microbiota and an overall increase in microbial diversity consistent with previous studies after FMT. FMT was successful in treating CDI using a diverse set of donors, and varying degrees of donor stool engraftment suggesting that donor type and degree of engraftment are not drivers of a successful FMT treatment of CDI. However, patients with underlying IBD experienced an increased number of CDI relapses (during a 24-month follow-up) and a decreased growth of new taxa, as compared to the subjects without IBD. Moreover, the need for IBD therapy did not change following FMT. These results underscore the importance of the existing gut microbial landscape as a decisive factor to successfully treat CDI and potentially for improvement of the underlying pathophysiology in IBD.

CONCLUSIONS

FMT leads to a significant change in microbial diversity in patients with recurrent CDI and complete resolution of symptoms. Stool donor type (related or unrelated) and degree of engraftment are not the key for successful treatment of CDI by FMT. However, CDI patients with IBD have higher proportion of the original community after FMT and lack of improvement of their IBD symptoms and increased episodes of CDI on long-term follow-up.

Management of Clostridium difficile Infection in Inflammatory Bowel Disease: Expert Review from the Clinical Practice Updates Committee of the AGA Institute

The purpose of this expert review is to synthesize the existing evidence on the management of Clostridium difficile infection in patients with underlying inflammatory bowel disease. The evidence reviewed in this article is a summation of relevant scientific publications, expert opinion statements, and current practice guidelines. This review is a summary of expert opinion in the field without a formal systematic review of evidence. Best Practice Advice 1: Clinicians should test patients who present with a flare of underlying inflammatory bowel disease for Clostridium difficile infection. Best Practice Advice 2: Clinicians should screen for recurrent C difficile infection if diarrhea or other symptoms of colitis persist or return after antibiotic treatment for C difficile infection. Best Practice Advice 3: Clinicians should consider treating C difficile infection in inflammatory bowel disease patients with vancomycin instead of metronidazole. Best Practice Advice 4: Clinicians strongly should consider hospitalization for close monitoring and aggressive management for inflammatory bowel disease patients with C difficile infection who have profuse diarrhea, severe abdominal pain, a markedly increased peripheral blood leukocyte count, or other evidence of sepsis. Best Practice Advice 5: Clinicians may postpone escalation of steroids and other immunosuppression agents during acute C difficile infection until therapy for C difficile infection has been initiated. However, the decision to withhold or continue immunosuppression in inflammatory bowel disease patients with C difficile infection should be individualized because there is insufficient existing robust literature on which to develop firm recommendations. Best Practice Advice 6: Clinicians should offer a referral for fecal microbiota transplantation to inflammatory bowel disease patients with recurrent C difficile infection.

Clostridium difficile infection: new insights into management

Clostridium difficile was first described as a cause of diarrhea in 1978 and is now among the leading 3 hospital-acquired infections in the United States, along with methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci. In the past 2 decades, there has been an increase in the incidence, severity, and recurrence rates of C difficile infection, all of which are associated with poor outcomes. In addition, several novel risk factors and newer treatment methods are emerging, including fidaxomicin therapy, treatment using monoclonal antibodies, and fecal microbiota transplantation, that have shown promise for the treatment of C difficile infection. This review focuses on the changing epidemiology, risk factors, and newer methods for treatment of C difficile infection.

Results From a Randomized, Placebo-Controlled Clinical Trial of a RBX2660-A Microbiota-Based Drug for the Prevention of Recurrent Clostridium difficile Infection

BACKGROUND

Despite advancements, recurrent Clostridium difficile infections (CDI) remain an urgent public health threat with insufficient response rates to currently approved antibiotic therapies. Microbiota-based treatments appear effective, but rigorous clinical trials are required to optimize dosing strategies and substantiate long-term safety.

METHODS

This randomized, double-blind, placebo-controlled phase 2B trial enrolled adults with 2 or more CDI recurrences to receive: 2 doses of RBX2660, a standardized microbiota-based drug (group A); 2doses of placebo (group B); or 1 dose of RBX2660 followed by 1 dose of placebo (group C). Efficacy was defined as prevention of recurrent CDI for 8 weeks following treatment. Participants who had a recurrence within 8 weeks were eligible to receive up to 2 open-label RBX2660 doses. The primary endpoint was efficacy for group A compared to group B. Secondary endpoints included the efficacy of group C compared to group B, combined efficacy in the blinded and open-label phases, and safety for 24 months.

RESULTS

The efficacy for groups A, B, and C were 61%, 45%, and 67%, respectively. The primary endpoint was not met (P = .152). One RBX2660 dose (group C) was superior to placebo (group B; P = .048), and the overall efficacy (including open-label response) for RBX2660-treated participants was 88.8%. Adverse events did not differ significantly among treatment groups.

CONCLUSIONS

One, but not 2, doses of RBX2660 was superior to placebo in this randomized, placebo-controlled trial. These data provide important insights for a larger phase 3 trial and continued clinical development of RBX2660.

CLINICAL TRIALS REGISTRATION

NCT02299570.

VE303, a Defined Bacterial Consortium, for Prevention of Recurrent Clostridioides difficile Infection: A Randomized Clinical Trial

IMPORTANCE

The effect of rationally defined nonpathogenic, nontoxigenic, commensal strains of Clostridia on prevention of Clostridioides difficile infection (CDI) is unknown.

OBJECTIVE

To determine the efficacy of VE303, a defined bacterial consortium of 8 strains of commensal Clostridia, in adults at high risk for CDI recurrence. The primary objective was to determine the recommended VE303 dosing for a phase 3 trial.

DESIGN, SETTING, AND PARTICIPANTS

Phase 2, randomized, double-blind, placebo-controlled, dose-ranging study conducted from February 2019 to September 2021 at 27 sites in the US and Canada. The study included 79 participants aged 18 years or older who were diagnosed with laboratory-confirmed CDI with 1 or more prior CDI episodes in the last 6 months and those with primary CDI at high risk for recurrence (defined as aged ≥75 years or ≥65 years with ≥1 risk factors: creatinine clearance <60 mL/min/1.73 m2, proton pump inhibitor use, remote [>6 months earlier] CDI history).

INTERVENTIONS

Participants were randomly assigned to high-dose VE303 (8.0 × 109 colony-forming units [CFUs]) (n = 30), low-dose VE303 (1.6 × 109 CFUs) (n = 27), or placebo capsules (n = 22) orally once daily for 14 days.

MAIN OUTCOMES AND MEASURES

The primary efficacy end point was the proportion of participants with CDI recurrence at 8 weeks using a combined clinical and laboratory definition. The primary efficacy end point was analyzed in 3 prespecified analyses, using successively broader definitions for an on-study CDI recurrence: (1) diarrhea consistent with CDI plus a toxin-positive stool sample; (2) diarrhea consistent with CDI plus a toxin-positive, polymerase chain reaction-positive, or toxigenic culture-positive stool sample; and (3) diarrhea consistent with CDI plus laboratory confirmation or (in the absence of a stool sample) treatment with a CDI-targeted antibiotic.

RESULTS

Baseline characteristics were similar across the high-dose VE303 (n = 29; 1 additional participant excluded from efficacy analysis), low-dose VE303 (n = 27), and placebo (n = 22) groups. The participants' median age was 63.5 years (range, 24-96); 70.5% were female; and 1.3% were Asian, 1.3% Black, 2.6% Hispanic, and 96.2% White. CDI recurrence rates through week 8 (using the efficacy analysis 3 definition) were 13.8% (4/29) for high-dose VE303, 37.0% (10/27) for low-dose VE303, and 45.5% (10/22) for placebo (P = .006, high-dose VE303 vs placebo).

CONCLUSIONS AND RELEVANCE

Among adults with laboratory-confirmed CDI with 1 or more prior CDI episodes in the last 6 months and those with primary CDI at high risk for recurrence, high-dose VE303 prevented recurrent CDI compared with placebo. A larger, phase 3 study is needed to confirm these findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03788434.

Fecal microbiota transplantation for the treatment of recurrent and severe Clostridium difficile infection in solid organ transplant recipients: A multicenter experience

Fecal microbiota transplant (FMT) is recommended for Clostridium difficile infection (CDI) treatment; however, use in solid organ transplantation (SOT) patients has theoretical safety concerns. This multicenter, retrospective study evaluated FMT safety, effectiveness, and risk factors for failure in SOT patients. Primary cure and overall cure were defined as resolution of diarrhea or negative C difficile stool test after a single FMT or after subsequent FMT(s) ± anti-CDI antibiotics, respectively. Ninety-four SOT patients underwent FMT, 78% for recurrent CDI and 22% for severe or fulminant CDI. FMT-related adverse events (AE) occurred in 22.3% of cases, mainly comprising self-limiting conditions including nausea, abdominal pain, and FMT-related diarrhea. Severe AEs occurred in 3.2% of cases, with no FMT-related bacteremia. After FMT, 25% of patients with underlying inflammatory bowel disease had worsening disease activity, while 14% of cytomegalovirus-seropositive patients had reactivation. At 3 months, primary cure was 58.7%, while overall cure was 91.3%. Predictors of failing a single FMT included inpatient status, severe and fulminant CDI, presence of pseudomembranous colitis, and use of non-CDI antibiotics at the time of FMT. These data suggest FMT is safe in SOT patients. However, repeated FMT(s) or additional antibiotics may be needed to optimize rates of cure with FMT.

Efficacy and safety of ridinilazole compared with vancomycin for the treatment of Clostridium difficile infection: a phase 2, randomised, double-blind, active-controlled, non-inferiority study

BACKGROUND

Clostridium difficile infection is the most common health-care-associated infection in the USA. We assessed the safety and efficacy of ridinilazole versus vancomycin for treatment of C difficile infection.

METHODS

We did a phase 2, randomised, double-blind, active-controlled, non-inferiority study. Participants with signs and symptoms of C difficile infection and a positive diagnostic test result were recruited from 33 centres in the USA and Canada and randomly assigned (1:1) to receive oral ridinilazole (200 mg every 12 h) or oral vancomycin (125 mg every 6 h) for 10 days. The primary endpoint was achievement of a sustained clinical response, defined as clinical cure at the end of treatment and no recurrence within 30 days, which was used to establish non-inferiority (15% margin) of ridinilazole versus vancomycin. The primary efficacy analysis was done on a modified intention-to-treat population comprising all individuals with C difficile infection confirmed by the presence of free toxin in stool who were randomly assigned to receive one or more doses of the study drug. The study is registered with ClinicalTrials.gov, number NCT02092935.

FINDINGS

Between June 26, 2014, and August 31, 2015, 100 patients were recruited; 50 were randomly assigned to receive ridinilazole and 50 to vancomycin. 16 patients did not complete the study, and 11 discontinued treatment early. The primary efficacy analysis included 69 patients (n=36 in the ridinilazole group; n=33 in the vancomycin group). 24 of 36 (66·7%) patients in the ridinilazole group versus 14 of 33 (42·4%) of those in the vancomycin group had a sustained clinical response (treatment difference 21·1%, 90% CI 3·1-39·1, p=0·0004), establishing the non-inferiority of ridinilazole and also showing statistical superiority at the 10% level. Ridinilazole was well tolerated, with an adverse event profile similar to that of vancomycin: 82% (41 of 50) of participants reported adverse events in the ridinilazole group and 80% (40 of 50) in the vancomycin group. There were no adverse events related to ridinilazole that led to discontinuation.

INTERPRETATION

Ridinilazole is a targeted-spectrum antimicrobial that shows potential in treatment of initial C difficile infection and in providing sustained benefit through reduction in disease recurrence. Further clinical development is warranted.

FUNDING

Wellcome Trust and Summit Therapeutics.

Community-acquired Clostridium difficile infection: an increasing public health threat

There has been a startling shift in the epidemiology of Clostridium difficile infection over the last decade worldwide, and it is now increasingly recognized as a cause of diarrhea in the community. Classically considered a hospital-acquired infection, it has now emerged in populations previously considered to be low-risk and lacking the traditional risk factors for C. difficile infection, such as increased age, hospitalization, and antibiotic exposure. Recent studies have demonstrated great genetic diversity for C. difficile, pointing toward diverse sources and a fluid genome. Environmental sources like food, water, and animals may play an important role in these infections, apart from the role symptomatic patients and asymptomatic carriers play in spore dispersal. Prospective strain typing using highly discriminatory techniques is a possible way to explore the suspected diverse sources of C. difficile infection in the community. Patients with community-acquired C. difficile infection do not necessarily have a good outcome and clinicians should be aware of factors that predict worse outcomes in order to prevent them. This article summarizes the emerging epidemiology, risk factors, and outcomes for community-acquired C. difficile infection.

Fecal Microbiota Transplantation for Recurrent Clostridium difficile Infection Reduces Recurrent Urinary Tract Infection Frequency

Broad-spectrum antibiotics for recurrent multidrug-resistant urinary tract infections (UTIs) disrupt the gut microbiome and promote antibiotic resistance. Fecal microbiota transplantation led to resolution of recurrent Clostridium difficile, significantly decreased recurrent UTI frequency, and improved antibiotic susceptibility profile of UTI-causing organisms.

Gut microbiome predictors of treatment response and recurrence in primary Clostridium difficile infection

BACKGROUND

Clostridium difficile infection (CDI) may not respond to initial therapy and frequently recurs, but predictors of response and recurrence are inconsistent. The impact of specific alterations in the gut microbiota determining treatment response and recurrence in patients with CDI is unknown.

AIM

To assess microbial signatures as predictors of treatment response and recurrence in CDI.

METHODS

Pre-treatment stool samples and clinical metadata including outcomes were collected prospectively from patients with their first CDI episode. Next generation 16s rRNA sequencing using MiSeq Illumina platform was performed and changes in microbial community structure were correlated with CDI outcomes.

RESULTS

Eighty-eight patients (median age 52.7 years, 60.2% female) were included. Treatment failure occurred in 12.5% and recurrence after response in 28.5%. Patients who responded to treatment had an increase in Ruminococcaceae, Rikenellaceae, Clostridiaceae, Bacteroides, Faecalibacterium and Rothia compared to nonresponders. A risk-index built from this panel of microbes differentiated responders (mean 0.07 ± 0.24) from nonresponders (0.52 ± 0.42; P = 0.0002). Receiver operating characteristic (ROC) curve demonstrated that risk-index was a strong predictor of treatment response with an area under the curve (AUC) of 0.85. Among clinical parameters tested, only proton pump inhibitor use predicted recurrent CDI (OR 3.75, 95% CI 1.27-11.1, P = 0.01). Patients with recurrent CDI had statistically significant increases in Veillonella, Enterobacteriaceae, Streptococci, Parabacteroides and Lachnospiraceae compared to patients without recurrence and a risk index was able to predict recurrence (AUC = 0.78).

CONCLUSION

Gut microbiota signatures predict treatment response and recurrence potentially, allowing identification of patients with Clostridium difficile infection that may benefit from early institution of alternate therapies.

2019 update of the WSES guidelines for management of Clostridioides (Clostridium) difficile infection in surgical patients

In the last three decades, Clostridium difficile infection (CDI) has increased in incidence and severity in many countries worldwide. The increase in CDI incidence has been particularly apparent among surgical patients. Therefore, prevention of CDI and optimization of management in the surgical patient are paramount. An international multidisciplinary panel of experts from the World Society of Emergency Surgery (WSES) updated its guidelines for management of CDI in surgical patients according to the most recent available literature. The update includes recent changes introduced in the management of this infection.