Diarrhoea in general practice: when should a Clostridium difficile infection be considered? Results of a nested case-control study

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.

Diagnostic Guidance for C. difficile Infections

Diagnosis of Clostridioides difficile infection (CDI) can be challenging. First of all, there has been debate on which of the two reference assays, cell cytotoxicity neutralization assay (CCNA) or toxigenic culture (TC), should be considered the gold standard for CDI detection. Although the CCNA suffers most from suboptimal storage conditions and subsequent toxin degradation, TC is reported to falsely increase CDI detection rates as it cannot differentiate CDI patients from patients asymptomatically colonised by toxigenic C. difficile. Several rapid assays are available for CDI detection and fall into three broad categories: (1) enzyme immunoassays for glutamate dehydrogenase, (2) enzyme immunoassays or single-molecule array assays for toxins A/B and (3) nucleic acid amplification tests detecting toxin genes. All three categories have their own limitations, being suboptimal specificity and/or sensitivity or the inability to discern colonised patients from CDI patients. In light of these limitations, multi-step algorithmic testing has been advocated by international guidelines (IDSA/SHEA and ESCMID) in order to optimize diagnostic accuracy. As a result, a survey performed in 2018-2019 in Europe revealed that most of all hospital sites reported using more than one test to diagnose CDI. CDI incidence rates are also influenced by sample selection criteria, as several studies have shown that if not all unformed stool samples are tested for CDI, many cases may be missed due to an absence of clinical suspicion. Since methods for diagnosing CDI remain imperfect, there has been a growing interest in alternative testing strategies like faecal microbiota biomarkers, immune modulating interleukins, cytokines and imaging methods. At the moment, these alternative methods might play an adjunctive role, but they are not suitable to replace conventional CDI testing strategies.

2'-Fucosyllactose inhibits proliferation of Clostridioides difficile ATCC 43599 in the CDi-screen, an in vitro model simulating Clostridioides difficile infection

BACKGROUND

Clostridioides difficile is a Gram-positive anaerobic bacterium that can produce the toxins TcdA and/or TcdB and is considered an opportunistic pathogen. C. difficile is mainly transmitted as endospores, which germinate to produce the pathogenic vegetative cells under suitable conditions in the gut. To efficiently screen novel therapeutic- interventions against the proliferation of C. difficile within a complex microbial community, platforms are needed that facilitate parallel experimentation. In order to allow for screening of novel interventions a medium-to-high throughput in vitro system is desirable. To this end, we have developed the 96-well CDi-screen platform that employs an adapted simulated ileal effluent medium (CDi-SIEM) and allows for culturing of pathogenic C. difficile.

METHODS

C. difficile strain ATCC 43599 was inoculated in the form of vegetative cells and spores into the CDi-screen in the presence and absence of a cultured fecal microbiota and incubated for 48h. To demonstrate its utility, we investigated the effect of the human milk oligosaccharide 2'-Fucosyllactose (2'-FL) at 4 and 8 mg/mL on C. difficile outgrowth and toxin production in the CDi-screen. The test conditions were sampled after 24 and 48 hours. C. difficile -specific primers were used to monitor C. difficile growth via qPCR and barcoded 16S rRNA gene amplicon sequencing facilitated the in-depth analysis of gut microbial community dynamics.

RESULTS

C. difficile ATCC 43599 proliferated in CDi-SIEM, both when inoculated as spores and as vegetative cells. The strain reached cell numbers expressed as C. difficile genome equivalents of up to 10 ⁸ cells per mL after 24h of incubation. 2'-FL significantly inhibited the outgrowth of the ATTC 43599 strain within a complex human gut microbial community in the CDi-screen. In addition, a dose-dependent modulation of the gut microbial community composition by 2'-FL supplementation was detected, with a significant increase in the relative abundance of the genus Blautia in the presence of 2'-FL.

CONCLUSION

The CDi-screen is suitable for studying C. difficile proliferation in a complex gut ecosystem and for screening for anti-pathogenic interventions that target C. difficile directly and/or indirectly through interactions with the gut microbiota. Different doses of compounds such as in this study the dose of the human milk oligosaccharide 2'-FL can be screened for efficacy in the inhibition of C. difficile proliferation.

A point-prevalence study on community and inpatient Clostridioides difficile infections (CDI): results from Combatting Bacterial Resistance in Europe CDI (COMBACTE-CDI), July to November 2018

BackgroundThere is a paucity of data on community-based Clostridioides difficile infection (CDI) and how these compare with inpatient CDI.AimTo compare data on the populations with CDI in hospitals vs the community across 12 European countries.MethodsFor this point-prevalence study (July-November 2018), testing sites sent residual diagnostic material on sampling days to a coordinating laboratory for CDI testing and PCR ribotyping (n = 3,163). Information on whether CDI testing was requested at the original site was used to identify undiagnosed CDI. We used medical records to identify differences between healthcare settings in patient demographics and risk factors for detection of C. difficile with or without free toxin.ResultsThe CDI positivity rate was 4.4% (country range: 0-16.2) in hospital samples, and 1.3% (country range: 0-2.2%) in community samples. The highest prevalence of toxinotype IIIb (027, 181 and 176) was seen in eastern European countries (56%; 43/77), the region with the lowest testing rate (58%; 164/281). Different predisposing risk factors were observed (use of broad-spectrum penicillins in the community (OR: 8.09 (1.9-35.6), p = 0.01); fluoroquinolones/cephalosporins in hospitals (OR: 2.2 (1.2-4.3), p = 0.01; OR: 2.0 (1.1-3.7), p = 0.02)). Half of community CDI cases were undetected because of absence of clinical suspicion, accounting for three times more undiagnosed adults in the community compared with hospitals (ca 111,000 vs 37,000 cases/year in Europe).ConclusionThese findings support recommendations for improving diagnosis in patients presenting with diarrhoea in the community, to guide good practice to limit the spread of CDI.

Management and characteristics of patients suffering from Clostridiodes difficile infection in primary care

Background

Clostridioides difficile infection (CDI) is rising and increases patient healthcare costs due to extended hospitalisation, tests and medications. Management of CDI in French primary care is poorly reported.

Objectives

To characterise patients suffering from CDI, managed in primary care and describe their clinical outcomes.

Methods

Retrospective observational study based on survey data among 500 randomly selected General Practitioners (GPs) surveyed in France from September 2018 to April 2019. GPs were asked to complete a multiple-choice questionnaire for each reported patient presenting a CDI. Responses were analysed according to clinical characteristics. Treatment strategies were compared according to the outcome: recovery or recurrent infection.

Results

Participation rate was 8.6% (n = 43/500) with two incomplete questionnaires. Data from 41 patients with an actual diagnosis of CDI were analysed. Recovery was observed in 61% of patients with a confirmed diagnosis of CDI. In the recovery group, this was exclusively a primary episode, most patients (72%) had no comorbidities, were significantly younger (p = 0.02) than the ones who relapsed and 92% were successfully treated with oral metronidazole. Duration of diarrhoea after antimicrobial treatment initiation was significantly shorter in the recovery group (≤ 48 h) (p = 0.03). Cooperation with hospital specialists was reported in 28% of the recovery group versus 87.5% of the recurrent group (p = 0.0003). Overall, GPs managed successfully 82.9% of cases without need of hospital admission.

Conclusion

GPs provide relevant ambulatory care for mild primary episodes of CDI using oral metronidazole. Persistent diarrhoea despite an appropriate anti-Clostridiodes regimen should be interpreted as an early predictor of relapse.

How to: prophylactic interventions for prevention of Clostridioides difficile infection

BACKGROUND

Clostridioides difficile infection (CDI) remains the leading cause of healthcare-associated diarrhoea, despite existing guidelines for infection control measures and antimicrobial stewardship. The high associated health and economic burden of CDI calls for novel strategies to prevent the development and spread of CDI in susceptible patients.

OBJECTIVES

We aim to review CDI prophylactic treatment strategies and their implementation in clinical practice.

SOURCES

We searched PubMed, Embase, Emcare, Web of Science, and the COCHRANE Library databases to identify prophylactic interventions aimed at prevention of CDI. The search was restricted to articles published in English since 2012.

CONTENT

A toxin-based vaccine candidate is currently being investigated in a phase III clinical trial. However, a recent attempt to develop a toxin-based vaccine has failed. Conventional probiotics have not yet proved to be an effective strategy for prevention of CDI. New promising microbiota-based interventions that bind and inactivate concomitantly administered antibiotics, such as ribaxamase and DAV-132, have been developed. Prophylaxis of CDI with C. difficile antibiotics should not be performed routinely and should be considered only for secondary prophylaxis in very selected patients who are at the highest imminent risk for recurrent CDI (R-CDI) after a thorough evaluation. Faecal microbiota transplantation (FMT) has proved to be a very effective treatment for patients with multiple recurrences. Bezlotoxumab provides protection against R-CDI, mainly in patients with primary episodes and a high risk of relapse.

IMPLICATIONS

There are no proven effective, evidenced-based prophylaxis options for primary CDI. As for secondary prevention, FMT is considered the option of choice in patients with multiple recurrences. Bezlotoxumab can be added to standard treatment for patients at high risk for R-CDI. The most promising strategies are those aimed at reducing changes in intestinal microbiota and development of a new effective non-toxin-based vaccine.

A Review of Clostridioides difficile Infection and Antibiotic-Associated Diarrhea

Antibiotic-associated diarrhea and Clostridioides difficile infection (CDI) occur frequently among adults. The pathophysiology of CDI is related to disruption of normal gut flora and risk factors include hospitalization, use of antibiotic therapy, and older age. Clinical manifestations can range from mild disease to toxic megacolon. Diagnosis is challenging and is based on a combination of clinical symptoms and diagnostic tests. Therapy includes cessation of antibiotics, or use of other agents depending on the severity of illness. Many novel agents for the treatment and prevention of CDI show promise and are under investigation.

Clostridioides difficile Infection, Still a Long Way to Go

Clostridioides difficile is an increasingly common pathogen both within and outside the hospital and is responsible for a large clinical spectrum from asymptomatic carriage to complicated infection associated with a high mortality. While diagnostic methods have considerably progressed over the years, the optimal diagnostic algorithm is still debated and there is no single diagnostic test that can be used as a standalone test. More importantly, the heterogeneity in diagnostic practices between centers along with the lack of robust surveillance systems in all countries and an important degree of underdiagnosis due to lack of clinical suspicion in the community, hinder a more accurate evaluation of the burden of disease. Our improved understanding of the physiopathology of CDI has allowed some significant progress in the treatment of CDI, including a broader use of fidaxomicine, the use of fecal microbiota transplantation for multiples recurrences and newer approaches including antibodies, vaccines and new molecules, already developed or in the pipeline. However, the management of CDI recurrences and severe infections remain challenging and the main question remains: how to best target these often expensive treatments to the right population. In this review we discuss current diagnostic approaches, treatment and potential prevention strategies, with a special focus on recent advances in the field as well as areas of uncertainty and unmet needs and how to address them.

Modelling diverse sources of Clostridium difficile in the community: importance of animals, infants and asymptomatic carriers

Clostridium difficile infections (CDIs) affect patients in hospitals and in the community, but the relative importance of transmission in each setting is unknown. We developed a mathematical model of C. difficile transmission in a hospital and surrounding community that included infants, adults and transmission from animal reservoirs. We assessed the role of these transmission routes in maintaining disease and evaluated the recommended classification system for hospital- and community-acquired CDIs. The reproduction number in the hospital was <1 (range: 0.16–0.46) for all scenarios. Outside the hospital, the reproduction number was >1 for nearly all scenarios without transmission from animal reservoirs (range: 1.0–1.34). However, the reproduction number for the human population was <1 if a minority (>3.5–26.0%) of human exposures originated from animal reservoirs. Symptomatic adults accounted for <10% transmission in the community. Under conservative assumptions, infants accounted for 17% of community transmission. An estimated 33–40% of community-acquired cases were reported but 28–39% of these reported cases were misclassified as hospital-acquired by recommended definitions. Transmission could be plausibly sustained by asymptomatically colonised adults and infants in the community or exposure to animal reservoirs, but not hospital transmission alone. Under-reporting of community-onset cases and systematic misclassification underplays the role of community transmission.

The recent emergence of a highly related virulent Clostridium difficile clade with unique characteristics

OBJECTIVES

Clostridium difficile is a major global human pathogen divided into five clades, of which clade 3 is the least characterized and consists predominantly of PCR ribotype (RT) 023 strains. Our aim was to analyse and characterize this clade.

METHODS

In this cohort study the clinical presentation of C. difficile RT023 infections was analysed in comparison with known 'hypervirulent' and non-hypervirulent strains, using data from the Netherlands national C. difficile surveillance programme. European RT023 strains of diverse origin were collected and whole-genome sequenced to determine the genetic similarity between isolates. Distinctive features were investigated and characterized.

RESULTS

Clinical presentation of C. difficile RT023 infections show severe infections akin to those seen with 'hypervirulent' strains from clades 2 (RT027) and 5 (RT078) (35%, 29% and 27% severe CDI, respectively), particularly with significantly more bloody diarrhoea than RT078 and non-hypervirulent strains (RT023 8%, other RTs 4%, p 0.036). The full genome sequence of strain CD305 is presented as a robust reference. Phylogenetic comparison of CD305 and a further 79 previously uncharacterized European RT023 strains of diverse origin revealed minor genetic divergence with >99.8% pairwise identity between strains. Analyses revealed distinctive features among clade 3 strains, including conserved pathogenicity locus, binary toxin and phage insertion toxin genotypes, glycosylation of S-layer proteins, presence of the RT078 four-gene trehalose cluster and an esculinase-negative genotype.

CONCLUSIONS

Given their recent emergence, virulence and genomic characteristics, the surveillance of clade 3 strains should be more highly prioritized.

Clostridioides difficile: diagnosis and treatments

Clostridioides difficile (formerly Clostridium) is a major cause of healthcare associated diarrhea, and is increasingly present in the community. Historically, C difficile infection was considered easy to diagnose and treat. Over the past two decades, however, diagnostic techniques have changed in line with a greater understanding of the physiopathology of C difficile infection and the use of new therapeutic molecules. The evolution of diagnosis showed there was an important under- and misdiagnosis of C difficile infection, emphasizing the importance of algorithms recommended by European and North American infectious diseases societies to obtain a reliable diagnosis. Previously, metronidazole was considered the reference drug to treat C difficile infection, but more recently vancomycin and other newer drugs are shown to have higher cure rates. Recurrence of infection represents a key parameter in the evaluation of new drugs, and the challenge is to target the right population with the adapted therapeutic molecule. In multiple recurrences, fecal microbiota transplantation is recommended. New approaches, including antibodies, vaccines, and new molecules are already available or in the pipeline, but more data are needed to support the inclusion of these in practice guidelines. This review aims to provide a baseline for clinicians to understand and stratify their choice in the diagnosis and treatment of C difficile infection based on the most recent data available.

Global burden of Clostridium difficile infections: a systematic review and meta-analysis

Background

Clostridium difficile is a leading cause of morbidity and mortality in several countries. However, there are limited evidence characterizing its role as a global public health problem. We conducted a systematic review to provide a comprehensive overview of C. difficile infections (CDI) rates.

Methods

Seven databases were searched (January 2016) to identify studies and surveillance reports published between 2005 and 2015 reporting CDI incidence rates. CDI incidence rates for health care facility-associated (HCF), hospital onset-health care facility-associated, medical or general intensive care unit (ICU), internal medicine (IM), long-term care facility (LTCF), and community-associated (CA) were extracted and standardized. Meta-analysis was conducted using a random effects model.

Results

229 publications, with data from 41 countries, were included. The overall rate of HCF-CDI was 2.24 (95% confidence interval CI = 1.66-3.03) per 1000 admissions/y and 3.54 (95%CI = 3.19-3.92) per 10 000 patient-days/y. Estimated rates for CDI with onset in ICU or IM wards were 11.08 (95%CI = 7.19-17.08) and 10.80 (95%CI = 3.15-37.06) per 1000 admission/y, respectively. Rates for CA-CDI were lower: 0.55 (95%CI = 0.13-2.37) per 1000 admissions/y. CDI rates were generally higher in North America and among the elderly but similar rates were identified in other regions and age groups.

Conclusions

Our review highlights the widespread burden of disease of C. difficile, evidence gaps, and the need for sustainable surveillance of CDI in the health care setting and the community.

Toxigenic Clostridium difficile carriage in general practice: results of a laboratory-based cohort study

OBJECTIVES

Reported rates of community-acquired Clostridium difficile infections (CDIs) have been increasing. However, the true burden of the disease in general practice is unknown in France. Our objective was to determine the incidence of toxigenic C. difficile carriage and the percentage of stool samples prescribed by general practitioners (GPs) which contained free C. difficile toxins.

METHODS

During an 11-month period, all stool samples submitted for any enteric pathogen detection to 15 different private laboratories in Paris and the surrounding areas were tested for C. difficile, irrespective of the GPs' request. A clinical questionnaire was completed for each patient. Stool samples were screened using a rapid simultaneous glutamate dehydrogenase and toxins A/B detection test: any positive result (glutamate dehydrogenase or toxin) was further confirmed by the stool cytotoxicity assay (CTA) on MRC-5 cells and by toxigenic culture (TC) at a central laboratory. The C. difficile isolates were characterized by PCR ribotyping.

RESULTS

A total of 2541 patients (1295 female, 1246 male) were included. The incidences of patients with a positive toxigenic culture and a positive CTA were 3.27% (95% CI 2.61%-4.03%) and 1.81% (95% CI 1.33%-2.41%), respectively. GPs requested C. difficile testing in only 12.93% of the stool samples, detecting 52.30% of all TC-positive patients. The 83 toxigenic C. difficile strains belonged to 36 different PCR ribotypes.

CONCLUSIONS

Toxigenic C. difficile carriage is frequent in general practice but remains under-recognized. It may affect young patients without previous antimicrobial therapy or hospitalization.

Spatial clustering and livestock exposure as risk factor for community-acquired Clostridium difficile infection

OBJECTIVES

Clostridium difficile infections (CDI) account for 1.5% of diarrhoeic episodes in patients attending a general practitioner in the Netherlands, but its sources are unknown. We searched for community clusters to recognize localized point sources of CDI.

METHODS

Between October 2010 and February 2012, a community-based prospective nested case-control study was performed in three laboratories in the Netherlands with a study population of 2 810 830 people. Bernoulli spatial scan and space-time permutation models were used to detect spatial and/or temporal clusters of CDI. In addition, a multivariate conditional logistic regression model was constructed to test livestock exposure as a supposed risk factor in CDI patients without hospital admission within the previous 12 weeks (community-acquired (CA) CDI).

RESULTS

In laboratories A, B and C, 1.3%, 1.8% and 2.1% of patients with diarrhoea tested positive for CDI, respectively. The mean age of CA-CDI patients (n = 124) was 49 years (standard deviation, 22.6); 64.5% were female. No spatial or temporal clusters of CDI cases were detected compared to C. difficile-negative diarrhoeic controls. Except for one false-positive signal, no spatiotemporal interaction amongst CDI cases was found. Livestock exposure was not related to CA-CDI (odds ratio, 0.99; 95% confidence interval, 0.44-2.24). Ten percent of CA-CDIs was caused by PCR ribotype 078, spatially dispersed throughout the study area.

CONCLUSIONS

The absence of clusters of CDI cases in a community cohort of diarrhoeic patients suggests a lack of localized point sources of CDI in the living environment of these patients.

Quantitative Thresholds Enable Accurate Identification of Clostridium difficile Infection by the Luminex xTAG Gastrointestinal Pathogen Panel

Clostridium difficile colonizes the gastrointestinal (GI) tract, resulting in either asymptomatic carriage or a spectrum of diarrheal illness. If clinical suspicion for C. difficile is low, stool samples are often submitted for analysis by multiplex molecular assays capable of detecting multiple GI pathogens, and some institutions do not report this organism due to concerns for high false-positive rates. Since clinical disease correlates with organism burden and molecular assays yield quantitative data, we hypothesized that numerical cutoffs could be utilized to improve the specificity of the Luminex xTAG GI pathogen panel (GPP) for C. difficile infection. Analysis of cotested liquid stool samples (n = 1,105) identified a GPP median fluorescence intensity (MFI) value cutoff of ≥1,200 to be predictive of two-step algorithm (2-SA; 96.4% concordance) and toxin enzyme immunoassay (EIA) positivity. Application of this cutoff to a second cotested data set (n = 1,428) yielded 96.5% concordance. To determine test performance characteristics, concordant results were deemed positive or negative, and discordant results were adjudicated via chart review. Test performance characteristics for the MFI cutoff of ≥150 (standard), MFI cutoff of ≥1,200, and 2-SA were as follows (respectively): concordance, 95, 96, and 97%; sensitivity, 93, 78, and 90%; specificity, 95, 98, and 98%; positive predictive value, 67, 82, and 81%;, and negative predictive value, 99, 98, and 99%. To capture the high sensitivity for organism detection (MFI of ≥150) and high specificity for active infection (MFI of ≥1,200), we developed and applied a reporting algorithm to interpret GPP data from patients (n = 563) with clinician orders only for syndromic panel testing, thus enabling accurate reporting of C. difficile for 95% of samples (514 negative and 5 true positives) irrespective of initial clinical suspicion and without the need for additional testing.

The role of gut microbiota in Clostridium difficile infection

Clostridium difficile infection has emerged as a major health problem. Because it is a spore-forming microorganism, C. difficile is difficult to eradicate and recurrences of the infection are frequent. The strong association of CDI with prior use of antibiotics led to the recognition that disturbances in the gut microbiota apparently plays a central role in CDI. Except for antibiotics, several other risk factors for CDI have been recognised, such as advanced age and use of proton pump inhibitors. The common characteristic of these factors is that they are associated with changes in the composition of gut microbiota. Data from human studies have shown that the presence of C. difficile, either as a colonizer or as a pathogen, is associated with reduced microbiota diversity. C. difficile infection per se seems to be associated with changes in the representation of specific microbial populations (e.g. taxa) which either may act protectively against C. difficile colonization of the gut or may increase susceptibility for C. difficile infection. Therapeutic gut microbiota manipulation can be achieved by faecal microbiota transplantation, which is highly effective for the treatment of CDI.

Community- and Healthcare-Associated Clostridium difficile Infections, Finland, 2008-2013

Prudent use of antimicrobial drugs in outpatient settings is needed for reducing the burden of infection.

We evaluated incidence, case-fatality rate, and trends of community-associated (CA) and healthcare-associated (HA) Clostridium difficile infections (CDIs) in Finland during 2008–2013. CDIs were identified in the National Infectious Disease Register, deaths in the National Population Information System, hospitalizations to classify infections as CA or HA in the National Hospital Discharge Register, and genotypes in a reference laboratory. A total of 32,991 CDIs were identified: 10,643 (32.3%) were CA (32.9 cases/100,000 population) and 22,348 (67.7%) HA (69.1/100,000). Overall annual incidence decreased from 118.7/100,000 in 2008 to 92.1/100,000 in 2013, which was caused by reduction in HA-CDI rates (average annual decrease 8.1%; p<0.001). The 30-day case-fatality rate was lower for CA-CDIs than for HA-CDIs (3.2% vs. 13.3%; p<0.001). PCR ribotypes 027 and 001 were more common in HA-CDIs than in CA-CDIs. Although the HA-CDI incidence rate decreased, which was probably caused by increased awareness and improved infection control, the CA-CDI rate increased.

Diagnostic Guidance for C. difficile Infections

Diagnosis of Clostridium difficile infection (CDI) can be challenging. First of all, there has been debate on which of the two reference assays, cell cytotoxicity neutralization assay (CCNA) or toxigenic culture (TC) should be considered the gold standard for CDI detection. Although the CCNA suffers most from suboptimal storage conditions and subsequent toxin degradation, TC is reported to falsely increase CDI detection rates as it cannot differentiate CDI patients from patients asymptomatically colonised by toxigenic C. difficile. Several rapid assays are available for CDI detection and fall into three broad categories: (1) enzyme immunoassays for glutamate dehydrogenase, (2) enzyme immunoassays for toxins A/B and (3) nucleic acid amplification tests detecting toxin genes. All three categories have their own limitations, being suboptimal specificity and/or sensitivity or the inability to discern colonised patients from CDI patients. In light of these limitations, multi-step algorithmic testing has now been advocated by international guidelines in order to optimize diagnostic accuracy. Despite these recommendations, testing methods between hospitals vary widely, which impacts CDI incidence rates. CDI incidence rates are also influenced by sample selection criteria, as several studies have shown that if not all unformed stool samples are tested for CDI, many cases may be missed due to an absence of clinical suspicion. Since methods for diagnosing CDI remain imperfect, there has been a growing interest in alternative testing strategies like faecal biomarkers, immune modulating interleukins, cytokines and imaging methods. At the moment, these alternative methods might play an adjunctive role, but they are not suitable to replace conventional CDI testing strategies.

Ribotype 078 Clostridium difficile infection incidence in Dutch hospitals is not associated with provincial pig farming: Results from a national sentinel surveillance, 2009-2015

Background

It has been suggested that the high incidence of ribotype 078 Clostridium difficile infections (CDI) in the Netherlands is related to pig farming.

Methods

We used data of hospitalised CDI patients (>2yrs of age) diagnosed between May 2009 and May 2015 in 26 hospitals participating in a national sentinel surveillance. We compared clinical and geographical characteristics of 078 CDI to other CDI. We investigated the association between 078 CDI incidence and four indicators of pig farming (piglet, pig, piglet farm and pig farm density) by mixed-effects Poisson regression. We used a space-time permutation model to search for community-onset 078 CDI clusters (using SaTScan).

Results

A total of 4,691 CDI were identified. Ribotype 078 was isolated in 493 of 3,756 patients (13.1%) including a typing result. These patients had slightly higher community-onset disease and a 35% increase of 30-day mortality compared to non-078 CDI patients. The pooled overall and 078 incidence rates were 2.82 (95% CI, 2.42–3.29) and 0.26 (95% CI, 0.21–0.31) CDI per 10,000 patients-days respectively. Hospital 078 CDI incidence was not associated with provincial pig (IRR, 0.98; 95% CI, 0.89–1.08), piglet (IRR, 0.95; 95% CI, 0.75–1.19), pig farm (IRR, 1.08; 95% CI, 0.84–1.39), or piglet farm density (IRR, 1.00; 95% CI, 0.56–1.79). No clusters of community-onset ribotype 078 CDI were found.

Conclusions

Our results do not indicate that the ribotype 078 CDI incidence in hospitals is related to pig (farm) or piglet (farm) density. However, transmission beyond provincial borders or in non-hospitalised patients cannot be excluded.

How to: Surveillance of Clostridium difficile infections

BACKGROUND

The increasing incidence of Clostridium difficile infections (CDI) in healthcare settings in Europe since 2003 has affected both patients and healthcare systems. The implementation of effective CDI surveillance is key to enable monitoring of the occurrence and spread of C. difficile in healthcare and the timely detection of outbreaks.

AIMS

The aim of this review is to provide a summary of key components of effective CDI surveillance and to provide some practical recommendations. We also summarize the recent and current national CDI surveillance activities, to illustrate strengths and weaknesses of CDI surveillance in Europe.

SOURCES

For the definition of key components of CDI surveillance, we consulted the current European Society of Clinical Microbiology and Infectious Diseases (ESCMID) CDI-related guidance documents and the European Centre for Disease Prevention and Control (ECDC) protocol for CDI surveillance in acute care hospitals. To summarize the recent and current national CDI surveillance activities, we discussed international multicentre CDI surveillance studies performed in 2005-13. In 2017, we also performed a new survey of existing CDI surveillance systems in 33 European countries.

CONTENT

Key components for CDI surveillance are appropriate case definitions of CDI, standardized CDI diagnostics, agreement on CDI case origin definition, and the presentation of CDI rates with well-defined numerators and denominators. Incorporation of microbiological data is required to provide information on prevailing PCR ribotypes and antimicrobial susceptibility to first-line CDI treatment drugs. In 2017, 20 European countries had a national CDI surveillance system and 21 countries participated in ECDC-coordinated CDI surveillance. Since 2014, the number of centres with capacity for C. difficile typing has increased to 35 reference or central laboratories in 26 European countries.

IMPLICATIONS

Incidence rates of CDI, obtained from a standardized CDI surveillance system, can be used as an important quality indicator of healthcare at hospital as well as country level.

Clostridium difficile classification overestimates hospital-acquired infections

BACKGROUND

Clostridium difficile infections occur frequently among hospitalized patients, with some infections acquired in hospital and others in the community. International guidelines classify cases as hospital-acquired if symptom onset occurs more than two days after admission. This classification informs surveillance and infection control, but has not been verified by empirical or modelling studies.

AIM

To assess current classification of C. difficile acquisition using a simulation model as a reference standard.

METHODS

C. difficile transmission was simulated in a range of hospital scenarios. The sensitivity, specificity and precision of classifications that use cut-offs ranging from 0.25 h to 40 days were calculated. The optimal cut-off that correctly estimated the proportion of cases that were hospital acquired and the balanced cut-off that had equal sensitivity and specificity were identified.

FINDINGS

The recommended two-day cut-off overestimated the incidence of hospital-acquired cases in all scenarios and by >100% in the base scenario. The two-day cut-off had good sensitivity (96%) but poor specificity (48%) and precision (52%) to identify cases acquired during the current hospitalization. A five-day cut-off was balanced, and a six-day cut-off was optimal in the base scenario. The optimal and balanced cut-offs were more than two days for nearly all scenarios considered (ranges: four to nine days and two to eight days, respectively).

CONCLUSION

Current guidelines for classifying C. difficile infections overestimate the proportion of cases acquired in hospital in all model scenarios. To reduce misclassification bias, an infection should be classified as being acquired prior to admission if symptoms begin within five days of admission.

Prevalence and risk factors for colonization of Clostridium difficile among adults living near livestock farms in the Netherlands

A cross-sectional study was performed among 2494 adults not living or working on a farm to assess prevalence of Clostridium difficile (CD) colonization and risk factors in a livestock dense area. CD prevalence was 1·2%. Twenty-one persons were colonized with a toxigenic strain and nine with a non-toxigenic strain. CD-positive persons did not live closer to livestock farms than individuals negative for CD. Antibiotic exposure in the preceding 3 months was a risk factor for CD colonization (odds ratio 3·70; 95% confidence interval 1·25-10·95).

Detection of Clostridium difficile in Feces of Asymptomatic Patients Admitted to the Hospital

Recent evidence shows that patients asymptomatically colonized with Clostridium difficile may contribute to the transmission of C. difficile in health care facilities. Additionally, these patients may have a higher risk of developing C. difficile infection. The aim of this study was to compare a commercially available PCR directed to both toxin A and B (artus C. difficile QS-RGQ kit CE; Qiagen), an enzyme-linked fluorescent assay to glutamate dehydrogenase (GDH ELFA) (Vidas, bioMérieux), and an in-house-developed PCR to tcdB, with (toxigenic) culture of C. difficile as the gold standard to detect asymptomatic colonization. Test performances were evaluated in a collection of 765 stool samples obtained from asymptomatic patients at admission to the hospital. The C. difficile prevalence in this collection was 5.1%, and 3.1% contained toxigenic C. difficile Compared to C. difficile culture, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the C. difficile GDH ELFA were 87.2%, 91.2%, 34.7%, and 99.3%, respectively. Compared with results of toxigenic culture, the sensitivity, specificity, PPV, and NPV of the commercially available PCR and the in-house PCR were 95.8%, 93.4%, 31.9%, 99.9%, and 87.5%, 98.8%, 70%, and 99.6%, respectively. We conclude that in a low-prevalence setting of asymptomatically colonized patients, both GDH ELFA and a nucleic acid amplification test can be applied as a first screening test, as they both display a high NPV. However, the low PPV of the tests hinders the use of these assays as stand-alone tests.

Epidemiology and outcome of Clostridium difficile infections in patients hospitalized in Internal Medicine: findings from the nationwide FADOI-PRACTICE study

Background

Clostridium difficile (CD) is a leading cause of diarrhoea among hospitalized patients. The objective of this study was to evaluate the rate, the optimal diagnostic work-up, and outcome of CD infections (CDI) in Internal Medicine (IM) wards in Italy.

Methods

PRACTICE is an observational prospective study, involving 40 IM Units and evaluating all consecutive patients hospitalized during a 4-month period. CDI were defined in case of diarrhoea when both enzyme immunoassay for GDH, and test for A/B toxin were positive. Patients with CDI were followed-up for recurrences for 4 weeks after the end of therapy.

Results

Among the 10,780 patients observed, 103 (0.96 %) showed CDI, at admission or during hospitalization. A positive history for CD, antibiotics in the previous 4 weeks, recent hospitalization, female gender and age were significantly associated with CDI (multivariable analysis). In-hospital mortality was 16.5 % in CD group vs 6.7 % in No-CD group (p < 0.001), whereas median length of hospital stay was 16 (IQR = 13) vs 8 (IQR = 8) days (p < 0.001) among patients with or without CDI, respectively. Rate of CD recurrences was 14.6 %. As a post-hoc evaluation, 23 out of 34 GDH+/Tox- samples were toxin positive, when analysed by molecular method (a real-time PCR assay). The overall CD incidence rate was 5.3/10,000 patient-days.

Conclusions

Our results confirm the severity of CDI in medical wards, showing high in-hospital mortality, prolonged hospitalization and frequent short-term recurrences. Further, our survey supports a 2–3 step algorithm for CD diagnosis: EIA for detecting GDH, A and B toxin, followed by a molecular method in case of toxin-negative samples.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1961-9) contains supplementary material, which is available to authorized users.

Clostridium difficile environmental contamination within a clinical laundry facility in the USA

Clostridium difficile is both a hospital and community-acquired pathogen. The current study determined if C. difficile could be cultured from clinical laundry facility surfaces. A total of 240 surface samples were collected from dirty areas (n = 120), which handle soiled clinical linens, and from clean areas (n = 120), which process and fold the clean linens, within the University of Washington Consolidated Laundry facility in 2015. Sampling was done four times over the course of 1 year. The dirty area was significantly more contaminated than the clean area (21% vs 2%, P < 0.001). Clostridium difficile isolates were genetically characterized using multilocus sequence typing and PCR for the detection of genes encoding toxin A and toxin B. The MLST types 1, 2, 3, 15, 26, 34, 35, 39, 42, 43, 44, 53, 63 and 284 were identified and have previously been found in both clinical and community settings. Toxin positive isolates were identified in both the dirty (n = 16/25) and clean areas (n = 2/2). Seasonal variation was observed with 40% of the 27 isolates cultured in April 2015. The study suggests that soiled clinical linens may be a source of C. difficile surface contamination.

Feasibility of reusing time-matched controls in an overlapping cohort

The methods developed for secondary analysis of nested case-control data have been illustrated only in simplified settings in a common cohort and have not found their way into biostatistical practice. This paper demonstrates the feasibility of reusing prior nested case-control data in a realistic setting where a new outcome is available in an overlapping cohort where no new controls were gathered and where all data have been anonymised. Using basic information about the background cohort and sampling criteria, the new cases and prior data are "aligned" to identify the common underlying study base. With this study base, a Kaplan-Meier table of the prior outcome extracts the risk sets required to calculate the weights to assign to the controls to remove the sampling bias. A weighted Cox regression, implemented in standard statistical software, provides unbiased hazard ratios. Using the method to compare cases of contralateral breast cancer to available controls from a prior study of metastases, we identified a multifocal tumor as a risk factor that has not been reported previously. We examine the sensitivity of the method to an imperfect weighting scheme and discuss its merits and pitfalls to provide guidance for its use in medical research studies.

European Society of Clinical Microbiology and Infectious Diseases: update of the diagnostic guidance document for Clostridium difficile infection

In 2009 the first European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guideline for diagnosing Clostridium difficile infection (CDI) was launched. Since then newer tests for diagnosing CDI have become available, especially nucleic acid amplification tests. The main objectives of this update of the guidance document are to summarize the currently available evidence concerning laboratory diagnosis of CDI and to formulate and revise recommendations to optimize CDI testing. This update is essential to improve the diagnosis of CDI and to improve uniformity in CDI diagnosis for surveillance purposes among Europe. An electronic search for literature concerning the laboratory diagnosis of CDI was performed. Studies evaluating a commercial laboratory test compared to a reference test were also included in a meta-analysis. The commercial tests that were evaluated included enzyme immunoassays (EIAs) detecting glutamate dehydrogenase, EIAs detecting toxins A and B and nucleic acid amplification tests. Recommendations were formulated by an executive committee, and the strength of recommendations and quality of evidence were graded using the Grades of Recommendation Assessment, Development and Evaluation (GRADE) system. No single commercial test can be used as a stand-alone test for diagnosing CDI as a result of inadequate positive predictive values at low CDI prevalence. Therefore, the use of a two-step algorithm is recommended. Samples without free toxin detected by toxins A and B EIA but with positive glutamate dehydrogenase EIA, nucleic acid amplification test or toxigenic culture results need clinical evaluation to discern CDI from asymptomatic carriage.

Enhanced surveillance of Clostridium difficile infection occurring outside hospital, England, 2011 to 2013

There are limited national epidemiological data for community-associated (CA)-Clostridium difficile infections (CDIs). Between March 2011 and March 2013, laboratories in England submitted to the Clostridium difficile Ribotyping Network (CDRN) up to 10 diarrhoeal faecal samples from successive patients with CA-CDI, defined here as C. difficile toxin-positive diarrhoea commencing outside hospital (or less than 48 hours after hospital admission), including those cases associated with community-based residential care, with no discharge from hospital within the previous 12 weeks. Patient demographics and C. difficile PCR ribotypes were compared for CA-CDIs in our study and presumed healthcare-associated (HA) CDIs via CDRN. Ribotype diversity indices, ranking and relative prevalences were very similar in CA- vs HA-CDIs, although ribotypes 002 (p ≤ 0.0001),020 (p = 0.009) and 056 (p < 0.0001) predominated in CA-CDIs; ribotype 027 (p = 0.01) predominated in HA-CDIs. Epidemic ribotypes 027 and 078 predominated in institutional residents with CDI (including care/nursing homes) compared with people with CDI living at home. Ribotype diversity decreased with increasing age in HA-CDIs, but not in CA-CDIs. Ribotype 078 CA-CDIs were significantly more common in elderly people (3.4% (6/174) vs 8.7% (45/519) in those aged < 65 and ≥ 65 years, respectively; p = 0.019). No antibiotics were prescribed in the previous four weeks in about twofold more CA-CDI vs HAs (38.6% (129/334) vs 20.3% (1,226/6,028); p < 0.0001). We found very similar ribotype distributions in CA- and HA-CDIs, although a few ribotypes significantly predominated in one setting. These national data emphasise the close interplay between, and likely common reservoirs for, CDIs, particularly when epidemic strains are not dominant.

Clostridium difficile infection

Infection of the colon with the Gram-positive bacterium Clostridium difficile is potentially life threatening, especially in elderly people and in patients who have dysbiosis of the gut microbiota following antimicrobial drug exposure. C. difficile is the leading cause of health-care-associated infective diarrhoea. The life cycle of C. difficile is influenced by antimicrobial agents, the host immune system, and the host microbiota and its associated metabolites. The primary mediators of inflammation in C. difficile infection (CDI) are large clostridial toxins, toxin A (TcdA) and toxin B (TcdB), and, in some bacterial strains, the binary toxin CDT. The toxins trigger a complex cascade of host cellular responses to cause diarrhoea, inflammation and tissue necrosis - the major symptoms of CDI. The factors responsible for the epidemic of some C. difficile strains are poorly understood. Recurrent infections are common and can be debilitating. Toxin detection for diagnosis is important for accurate epidemiological study, and for optimal management and prevention strategies. Infections are commonly treated with specific antimicrobial agents, but faecal microbiota transplants have shown promise for recurrent infections. Future biotherapies for C. difficile infections are likely to involve defined combinations of key gut microbiota.

Clostridium difficile infection: epidemiology, diagnosis and understanding transmission

Clostridium difficile infection (CDI) continues to affect patients in hospitals and communities worldwide. The spectrum of clinical disease ranges from mild diarrhoea to toxic megacolon, colonic perforation and death. However, this bacterium might also be carried asymptomatically in the gut, potentially leading to 'silent' onward transmission. Modern technologies, such as whole-genome sequencing and multi-locus variable-number tandem-repeat analysis, are helping to track C. difficile transmission across health-care facilities, countries and continents, offering the potential to illuminate previously under-recognized sources of infection. These typing strategies have also demonstrated heterogeneity in terms of CDI incidence and strain types reflecting different stages of epidemic spread. However, comparison of CDI epidemiology, particularly between countries, is challenging due to wide-ranging approaches to sampling and testing. Diagnostic strategies for C. difficile are complicated both by the wide range of bacterial targets and tests available and the need to differentiate between toxin-producing and non-toxigenic strains. Multistep diagnostic algorithms have been recommended to improve sensitivity and specificity. In this Review, we describe the latest advances in the understanding of C. difficile epidemiology, transmission and diagnosis, and discuss the effect of these developments on the clinical management of CDI.

Community-acquired Clostridium difficile infections

OBJECTIVE

To describe the management and treatment of community-acquired C. difficile infections (CDI) and to evaluate family physicians' (FP) knowledge and practice.

PATIENTS AND METHODS

Observational study from December 2013 to June 2014. All community-acquired CDI case patients diagnosed in the community or at the University Hospital of Nantes were prospectively included. A questionnaire was mailed to 150 FPs of the area of Nantes.

RESULTS

A total of 27 community-acquired CDI case patients were included (incidence: 7.7 case patients/100,000 inhabitants). Mean age was higher among case patients diagnosed at hospital (69years) compared with those diagnosed in the community (44years). Fifteen patients were treated at home (55%) and 22 received a first-line treatment with metronidazole. Only one patient did not receive any prior antibiotic treatment. Amoxicillin-clavulanic acid was mainly prescribed (68%) for respiratory and ENT infections (40%). Twenty-three patients were cured on Day 7 and three had complications (two deaths). Thirty-one of 47 FPs reported to have already managed CDI patients. Twenty-two FPs reported to usually treat patients with uncomplicated CDI at home, 21 to refer patients to a specialist, and three to hospital. Forty-one FPs reported to prescribe a CD toxin test only after recent antibiotic exposure and 30 when patients are at risk of CDI.

CONCLUSION

The incidence and impact of community-acquired CDIs may be underestimated and the unjustified use of antibiotics may promote their emergence. FPs are not used to treat CDIs as more than 50% prefer referring patients to hospital or to a specialist.

Antibacterials Developed to Target a Single Organism: Mechanisms and Frequencies of Reduced Susceptibility to the Novel Anti-Clostridium difficile Compounds Fidaxomicin and LFF571

Clostridium difficile is the most common cause of antibacterial-associated diarrhea. Clear clinical presentation and rapid diagnostics enable targeted therapy for C. difficile infection (CDI) to start quickly. CDI treatment includes metronidazole and vancomycin (VAN). Despite decades of use for CDI, no clinically meaningful resistance to either agent has emerged. Fidaxomicin (FDX), an RNA polymerase inhibitor, is also approved to treat CDI. Mutants with reduced susceptibility to FDX have been selected in vitro by single and multistep methods. Strains with elevated FDX minimum inhibitory concentrations (MICs) were also identified from FDX-treated patients in clinical trials. LFF571 is an exploratory agent that inhibits EF-Tu. In a proof-of-concept study, LFF571 was safe and effective for treating CDI. Spontaneous mutants with reduced susceptibility to LFF571 were selected in vitro in a single step, but not via serial passage. Although there are several agents in development for treatment of CDI, this review summarizes the frequencies and mechanisms of C. difficile mutants displaying reduced susceptibility to FDX or LFF71.

Asymptomatic carriers of toxigenic C. difficile in long-term care facilities: a meta-analysis of prevalence and risk factors

Background

The impact of Clostridium difficile colonization in C. difficile infection (CDI) is inadequately explored. As a result, asymptomatic carriage is not considered in the development of infection control policies and the burden of carrier state in long-term care facilities (LTCFs) is unknown.

Purpose

To explore the epidemiology of C. difficile colonization in LTCFs, identify predisposing factors and describe its impact on healthcare management.

Data Sources

PubMed, Embase and Web of Science (up to June 2014) without language restriction, complemented by reference lists of eligible studies.

Study Selection

All studies providing extractable data on the prevalence of toxigenic C. difficile colonization among asymptomatic residents in LTCFs.

Data Extraction

Two authors extracted data independently.

Statistical Methods

The pooled colonization estimates were calculated using the double arcsine methodology and reported along with their 95% random-effects confidence intervals (CIs), using DerSimonian-Laird weights. We assessed the impact of patient-level covariates on the risk of colonization and effects were reported as odds ratios (OR, 95% CI). We used the colonization estimates to simulate the effective reproduction number R through a Monte Carlo technique.

Results

Based on data from 9 eligible studies that met the specified criteria and included 1,371 subjects, we found that 14.8% (95%CI 7.6%-24.0%) of LTCF residents are asymptomatic carriers of toxigenic C. difficile. Colonization estimates were significantly higher in facilities with prior CDI outbreak (30.1% vs. 6.5%, p = 0.01). Patient history of CDI (OR 6.07; 95% CI 2.06–17.88; effect derived from 3 studies), prior hospitalization (OR 2.11; 95% CI 1.08–4.13; derived from 3 studies) and antimicrobial use within previous 3 months (OR 3.68; 95% CI 2.04–6.62; derived from 4 studies) were associated with colonization. The predicted colonization rate at admission was 8.9%.

Conclusion

Asymptomatic carriage of toxigenic C. difficile represents a significant burden in LTCFs and is associated with prior CDI outbreaks in the facility, a history of CDI, prior hospitalization and antimicrobial use. These findings can impact infection control measures at LTCFs.

Potential sources of Clostridium difficile in human infection

The view of Clostridium difficile infection as a hospital-acquired infection transmitted only by symptomatic patients is changing. Although C difficile is present in food for human consumption, food-borne infection caused by C difficile has never been confirmed. More information on the infective dose and the level of contamination is needed to determine the risk for food-borne exposure to C difficile in humans. The emergence of C difficile polymerase chain reaction (PCR) ribotype 078 in humans is epidemiologically linked to its presence in piglets and calves and their environment, suggesting zoonotic transmission.