Treatment of Clostridium difficile-associated disease: old therapies and new strategies

Clostridioides difficile infection: history, epidemiology, risk factors, prevention, clinical manifestations, treatment, and future options

SUMMARYClostridioides difficile infection (CDI) is one of the major issues in nosocomial infections. This bacterium is constantly evolving and poses complex challenges for clinicians, often encountered in real-life scenarios. In the face of CDI, we are increasingly equipped with new therapeutic strategies, such as monoclonal antibodies and live biotherapeutic products, which need to be thoroughly understood to fully harness their benefits. Moreover, interesting options are currently under study for the future, including bacteriophages, vaccines, and antibiotic inhibitors. Surveillance and prevention strategies continue to play a pivotal role in limiting the spread of the infection. In this review, we aim to provide the reader with a comprehensive overview of epidemiological aspects, predisposing factors, clinical manifestations, diagnostic tools, and current and future prophylactic and therapeutic options for C. difficile infection.

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

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

The role of microbiome-based therapeutics for the reduction and prevention of antimicrobial-resistant organism colonization

The gut is host to a diverse array of microbiota that constitute a complex ecological system crucial to human physiology. Disruptors to the normal host microbiota, such as antimicrobials, can cause a loss of species diversity in the gut, reducing its ability to resist colonization by invading pathogens and potentially leading to colonization with antimicrobial resistant organisms (AROs). ARO negatively impact gut health by disrupting the usual heterogeneity of gut microbiota and have the potential to cause systemic disease. In recent years, fecal microbiota transplantation (FMT) has been increasingly explored in the management of specific disease states such as Clostridioides difficile infection (CDI). Promising data from management of CDI has led to considerable interest in understanding the role of therapeutics to restore the gut microbiota to a healthy state. This review aims to discuss key studies that highlight the current landscape, and explore existing clinical evidence, for the use of FMT and microbiome-based therapeutics in combating intestinal colonization with ARO. We also explore potential future directions of such therapeutics and discuss unaddressed needs in this field that merit further investigation.

Biofilm Formation of Clostridioides difficile, Toxin Production and Alternatives to Conventional Antibiotics in the Treatment of CDI

Clostridioides difficile is considered a nosocomial pathogen that flares up in patients exposed to antibiotic treatment. However, four out of ten patients diagnosed with C. difficile infection (CDI) acquired the infection from non-hospitalized individuals, many of whom have not been treated with antibiotics. Treatment of recurrent CDI (rCDI) with antibiotics, especially vancomycin (VAN) and metronidazole (MNZ), increases the risk of experiencing a relapse by as much as 70%. Fidaxomicin, on the other hand, proved more effective than VAN and MNZ by preventing the initial transcription of RNA toxin genes. Alternative forms of treatment include quorum quenching (QQ) that blocks toxin synthesis, binding of small anion molecules such as tolevamer to toxins, monoclonal antibodies, such as bezlotoxumab and actoxumab, bacteriophage therapy, probiotics, and fecal microbial transplants (FMTs). This review summarizes factors that affect the colonization of C. difficile and the pathogenicity of toxins TcdA and TcdB. The different approaches experimented with in the destruction of C. difficile and treatment of CDI are evaluated.

The Novel DNA Binding Mechanism of Ridinilazole, a Precision Clostridiodes difficile Antibiotic

Clostridioides difficile infection (CDI) causes substantial morbidity and mortality worldwide with limited antibiotic treatment options. Ridinilazole is a precision bisbenzimidazole antibiotic being developed to treat CDI and reduce unacceptably high rates of infection recurrence in patients. Although in late clinical development, the precise mechanism of action by which ridinilazole elicits its bactericidal activity has remained elusive. Here, we present conclusive biochemical and structural data to demonstrate that ridinilazole has a primary DNA binding mechanism, with a co-complex structure confirming binding to the DNA minor groove. Additional RNA-seq data indicated early pleiotropic changes to transcription, with broad effects on multiple C. difficile compartments and significant effects on energy generation pathways particularly. DNA binding and genomic localization was confirmed through confocal microscopy utilizing the intrinsic fluorescence of ridinilazole upon DNA binding. As such, ridinilazole has the potential to be the first antibiotic approved with a DNA minor groove binding mechanism of action.

Novel Biomarkers, Including tcdB PCR Cycle Threshold, for Predicting Recurrent Clostridioides difficile Infection

Traditional clinical models for predicting recurrent Clostridioides difficile infection do not perform well, likely owing to the complex host-pathogen interactions involved. Accurate risk stratification using novel biomarkers could help prevent recurrence by improving underutilization of effective therapies (i.e., fecal transplant, fidaxomicin, bezlotoxumab). We used a biorepository of 257 hospitalized patients with 24 features collected at diagnosis, including 17 plasma cytokines, total/neutralizing anti-toxin B IgG, stool toxins, and PCR cycle threshold (CT) (a proxy for stool organism burden). The best set of predictors for recurrent infection was selected by Bayesian model averaging for inclusion in a final Bayesian logistic regression model. We then used a large PCR-only data set to confirm the finding that PCR CT predicts recurrence-free survival using Cox proportional hazards regression. The top model-averaged features were (probabilities of >0.05, greatest to least): interleukin 6 (IL-6), PCR CT, endothelial growth factor, IL-8, eotaxin, IL-10, hepatocyte growth factor, and IL-4. The accuracy of the final model was 0.88. Among 1,660 cases with PCR-only data, cycle threshold was significantly associated with recurrence-free survival (hazard ratio, 0.95; P < 0.005). Certain biomarkers associated with C. difficile infection severity were especially important for predicting recurrence; PCR CT and markers of type 2 immunity (endothelial growth factor [EGF], eotaxin) emerged as positive predictors of recurrence, while type 17 immune markers (IL-6, IL-8) were negative predictors. In addition to novel serum biomarkers (particularly, IL-6, EGF, and IL-8), the readily available PCR CT may be critical to augment underperforming clinical models for C. difficile recurrence.

Frequency of Diarrhea, Stool Specimen Collection and Testing, and Detection of Clostridioides Difficile Infection Among Hospitalized Adults in the Muenster/Coesfeld Area, Germany

Clostridioides difficile infection (CDI) often manifests as diarrhea, particularly in adults of older age or with underlying comorbidities. However, only severe cases are notifiable in Germany. Moreover, failure to collect a stool specimen from inpatients with diarrhea or incomplete testing may lead to underdiagnosis and underreporting of CDI. We assessed the frequency of diarrhea, stool specimen collection, and CDI testing to estimate CDI underdiagnosis and underreporting among hospitalized adults. In a ten-day point-prevalence study (2019-2021) of nine hospitals in a defined area (Muenster/Coesfeld, North Rhine-Westphalia, Germany), all diarrhea cases (≥ 3 loose stools in 24 h) among adult inpatients were captured via medical record screening and nurse interviews. Patient characteristics, symptom onset, putative origin, antibiotic consumption, and diagnostic stool sampling were collected in a case report form (CRF). Diagnostic results were retrieved from the respective hospital laboratories. Among 6998 patients screened, 476 (7%) diarrhea patients were identified, yielding a hospital-based incidence of 201 cases per 10,000 patient-days. Of the diarrheal patients, 186 (39%) had a stool sample collected, of which 160 (86%) were tested for CDI, meaning that the overall CDI testing rate among diarrhea patients was 34%. Toxigenic C. difficile was detected in 18 (11%) of the tested samples. The frequency of stool specimen collection and CDI testing among hospitalized diarrhea patients was suboptimal. Thus, CDI incidence in Germany is likely underestimated. To assess the complete burden of CDI in German hospitals, further investigations are needed.

Is Three Company or a Crowd? Comparing and Contrasting U.S. and European Clostridioidesdifficile Clinical Practice Guidelines

In 2021, the American College of Gastroenterology (ACG), the Infectious Diseases Society of America in conjunction with the Society for Healthcare Epidemiology of America (IDSA/SHEA), and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) published updated clinical practice guidelines (CPGs) for the management of Clostridioides difficile infections. The differences, sometimes subtle, between these guideline recommendations have caused some debate among clinicians. This paper delves into select key recommendations from each respective CPG and analyzes the differences and evidence associated with each. One primary difference between the CPGs is the preference given to fidaxomicin over vancomycin for initial treatment in non-severe and severe disease endorsed by IDSA/SHEA and ESCMID guidelines, while the ACG-sponsored CPGs do not offer a preference. The emphasis on cost effective data was also a noticeable difference between the CPGs and thus interpretation of the available evidence. When using guidelines to help support local practice or institutional treatment pathways, clinicians should carefully balance CPG recommendations with local patient populations and feasibility of implementation, especially when multiple guidelines for the same disease state exist.

Risk factors of first recurrence of Clostridioides difficile infection

OBJECTIVES

Clostridioides difficile infection (CDI) often recurs. Approximately 25% of patients have recurrences after the initial treatment, and patients who have relapsed once are more likely to relapse. We aimed to identify the risk factors for initial CDI recurrence.

METHODS

We performed a retrospective survey of patient backgrounds and treatment-related factors. Risk factors were analyzed using single and multiple logistic regression analyses.

RESULTS

A total of 134 patients were included in the study. Prophylactic probiotic use and nasogastric tube feeding were independent risk factors for the initial recurrence of CDI. Patients using prophylactic probiotics had significantly higher recurrence rates than those not using prophylactic probiotics.

CONCLUSION

Prophylactic probiotic use and nasogastric tube placement may be risk factors for the initial recurrence of CDI. It is noteworthy that CDI that occurs during the use of prophylactic probiotics may be prone to recurrence.

Fecal microbiota transplantation for recurrent Clostridioides difficile, safety, and pitfalls

Clostridioides difficile infection (CDI) is one of the leading causes of hospital-acquired infection attributing to substantial morbidity, mortality, and healthcare cost. Recurrent CDI (rCDI) is common and occurs after effective treatment of first episode. Treatment of rCDI is based on accurate diagnoses, due to difficulty in distinguishing between colonization of C. difficile spores or CDI; coronavirus disease 2019 (COVID-19) added to the complexity of diagnoses as both entities can co-occur. It is difficult to eradicate rCDI, and there remains a critical gap regarding treatment of rCDI. The treatment goal of rCDI is to reestablish normal microbiota. Fecal microbiota transplantation (FMT) is suggested as a treatment for second episode of rCDI. Based on the collective evidence of all randomized controlled trials, FMT was reported more efficacious compared with vancomycin or fidaxomicin; however, these trials had limited number of patients and all patients were pre-treated with vancomycin prior to FMT. Furthermore, when comparing various routes of instillation and types of preparation of fecal microbiota, no difference was observed in cure rate. Despite the success rate of FMT, there remains a concern for transmission of infectious agents, such as Gram negative bacteremia or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), adverse events (diarrhea and abdominal pain), and reports of new diagnoses (inflammatory bowel disease, weight gain and irritable bowel syndrome). To lessen the risk of transmissible infections, donor screening should be performed, which includes screening for medical comorbidities and infectious pathogens in blood and feces. Scheduling complexities and reimbursement places an additional roadblock for using FMT. Microbiome-based therapies are being developed to eliminate the logistical challenges related to FMT. Large prospective and placebo-controlled studies are needed to evaluate the efficacy and long-term safety of FMT, so its use can be justified in clinical practice.

Lacticaseibacillus casei Strain T21 Attenuates Clostridioides difficile Infection in a Murine Model Through Reduction of Inflammation and Gut Dysbiosis With Decreased Toxin Lethality and Enhanced Mucin Production

Clostridioides difficile is a major cause of diarrhea in patients with antibiotic administration. Lacticaseibacillus casei T21, isolated from a human gastric biopsy, was tested in a murine C. difficile infection (CDI) model and colonic epithelial cells (Caco-2 and HT-29). Daily administration of L. casei T21 [1 × 108 colony forming units (CFU)/dose] for 4 days starting at 1 day before C. difficile challenge attenuated CDI as demonstrated by a reduction in mortality rate, weight loss, diarrhea, gut leakage, gut dysbiosis, intestinal pathology changes, and levels of pro-inflammatory cytokines [interleukin (IL)-1β, tumor necrosis factor (TNF)-α, macrophage inflammatory protein 2 (MIP-2), and keratinocyte chemoattractant (KC)] in the intestinal tissue and serum. Conditioned media from L. casei T21 exerted biological activities that fight against C. difficile as demonstrated in colonic epithelial cells by the following: (i) suppression of gene expression and production of IL-8, an important chemokine involved in C. difficile pathogenesis, (ii) reduction in the expression of SLC11A1 (solute carrier family 11 member 1) and HuR (human antigen R), important genes for the lethality of C. difficile toxin B, (iii) augmentation of intestinal integrity, and (iv) up-regulation of MUC2, a mucosal protective gene. These results supported the therapeutic potential of L. casei T21 for CDI and the need for further study on the intervention capabilities of CDI.

Risk factors of surgical mortality in patients with Clostridium difficile colitis. A novel scoring system

BACKGROUND

The purpose of the study is to identify the risk factors of mortality and develop a risk scoring system in patients who underwent colectomy due to Clostridium difficile colitis (CD-C).

METHODS

Patient information was extracted using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) data from 2012 to 2016. All adult patients who underwent colectomy for CD-C were included in the study. The data were split into training and testing data sets. A multiple logistic regression model was developed by backward deletion methods for risk assessment. To test the performance of the prediction model for 30-day mortality, a receiver operating characteristic (ROC) curve was generated and an area under the curve (AUC) was created.

RESULTS

The training data set consisted of 434 (80%) patients, and the testing data set consisted of 91 (20%) patients. The overall mortality was 35%. No significant differences were found between the training and testing data sets for patient characteristics, comorbidities and mortality. The final model of the logistic regression model revealed a highly significant 30-day mortality for an age of ≥ 75 years old, ventilator dependency, Septic shock prior to surgery and a history of steroid use. The AUC value was 0.745 (95% CI 0.660-0.826). The risk of mortality scores range from 0 to 37. The highest score of 37 was related to an 83.9% predicted mortality.

CONCLUSION

Older age, septic shock, ventilator dependency requiring supportive care and a history of chronic steroid use were highly associated with mortality. A nomogram showing the scores and their relationship to mortality may provide guidance to point of care physicians for deciding the goal of care.

LEVEL OF EVIDENCE

Level of evidence: IV.

Impact of nisin on Clostridioides difficile and microbiota composition in a faecal fermentation model of the human colon

AIMS

Nisin is a bacteriocin with a broad spectrum of activity against Gram-positive bacteria. The aims were to assess nisin activity against Clostridioides difficile in a complex microbial environment and determine the minimum inhibitory concentration at which C. difficile growth is suppressed whilst having minimal impact on the faecal microbiota.

METHODS AND RESULTS

Faecal slurries were prepared from fresh faecal samples and spiked with C. difficile (10⁶  CFU per ml). Nisin was added to each fermentation at a range of concentrations from 0 to 500 µM. Following 24 h, 16S rRNA gene sequencing was performed, and the presence of viable C. difficile was assessed. There was no viable C. difficile detected in the presence of 50-500 µM nisin. There was a decrease in the diversity of the microbiota in a nisin dose-dependent manner. Nisin predominantly depleted the relative abundance of the Gram-positive bacteria whilst the relative abundance of Gram-negative bacteria such as Escherichia Shigella and Bacteroides increased.

CONCLUSIONS

Using an ex vivo model of the colon, this study demonstrates the ability of purified nisin to selectively deplete C. difficile in a faecal microbial environment and establishes the minimum concentration at which this occurs whilst having a minimal impact on the composition of the microbiota.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study opens up the potential to use nisin as a therapeutic for clostridial gut infections.

Pharmaceutical design of a delivery system for the bacteriocin lacticin 3147

Lacticin 3147 is a dual-acting two-peptide bacteriocin which is generally active against Gram-positive bacteria, including Listeria monocytogenes and antimicrobial-resistant bacteria such as Closteroides difficile in the colon. L. monocytogenes infections can cause life-long effects in the elderly and vulnerable and can cause severe complications in pregnant women. C. difficile causes one of the most common healthcare-associated infections and can be fatal in vulnerable groups such as the elderly. Although lacticin 3147 is degraded by intestinal proteases and has poor aqueous solubility, encapsulation of the bacteriocin could enable its use as an antimicrobial for treating these bacterial infections locally in the gastrointestinal tract. Lacticin 3147 displayed activity in aqueous solutions at a range of pH values and in gastric and intestinal fluids. Exposure to trypsin and α-chymotrypsin resulted in complete inactivation, implying that lacticin 3147 should be protected from these enzymes to achieve successful local delivery to the gastrointestinal tract. The amount of lacticin 3147 dissolved, i.e. its solution concentration, in water or buffered solutions at pH 1.6 and 7.4 was low and varied with time but increased and was stabilized in gastrointestinal fluids by the phospholipid and bile salt components present. Thus, the feasibility of a solid lipid nanoparticle (SLN) delivery system for local administration of lacticin 3147 was investigated. Bacteriocin activity was observed after encapsulation and release from a lipid matrix. Moreover, activity was seen after exposure to degrading enzymes. Further optimization of SLN delivery systems could enable the successful pharmaceutical development of active lacticin 3147 as an alternative to traditional antibiotics.

Budget Impact Analysis of Fidaxomicin Versus Vancomycin for the Treatment of Clostridioides difficile Infection in the United States

INTRODUCTION

Fidaxomicin is as effective as vancomycin in treating Clostridioides difficile infection (CDI) but more effective at preventing recurrence. However, because fidaxomicin is more costly than vancomycin, its overall value in managing CDI is not well understood. This study assessed the budget impact of introducing fidaxomicin versus vancomycin for the treatment of adults with CDI from a hospital perspective in the US.

METHODS

A cohort-based decision analytic model was developed over a 1-year horizon. A hospital with 10,000 annual hospitalizations was simulated. The model considered two adult populations: patients with no prior CDI episode and patients with one prior CDI episode. Two scenarios were assessed per population: 15% fidaxomicin/85% vancomycin use and 100% vancomycin use. Model inputs were obtained from published sources and expert opinion. Model outcomes included cost, payment, and revenue at the hospital level, per treated CDI patient, and per admitted patient. Budget impact was calculated as the difference in revenue between scenarios. One-way sensitivity analyses tested the effects of varying model inputs on the budget impact.

RESULTS

In patients with no prior CDI episode, treatment with fidaxomicin resulted in potential savings over 1 year of $1105 at the hospital level, $14 per treated CDI patient, and $0.11 per admitted patient. In patients with one prior CDI episode, fidaxomicin use was associated with potential savings over 1 year of $1150 at the hospital level, $74 per treated CDI patient, and $0.12 per admitted patient. Savings were driven by a reduced rate of CDI recurrence with fidaxomicin treatment and uptake of fidaxomicin. Sensitivity analyses indicated savings when inputs were varied in most scenarios.

CONCLUSION

Budgetary savings can be achieved with fidaxomicin due to reduced CDI recurrence as a result of a superior sustained clinical response. Our results support considering the broader benefits of fidaxomicin, beyond its cost, when making formulary inclusion decisions.

Costs Associated with the Treatment of Clostridioides Difficile Infections

Background: Clostridioides difficile, as the main cause of infectious diarrhoea in hospitalised patients, is a considerable challenge for medical personnel (hospital environment) who have direct contact with the patient, as well as being of interest to public health specialists. Financial issues related to the occurrence of the above-mentioned micro-organism are being increasingly raised. Due to the scale of the phenomenon, we are beginning to pay attention to the significant system costs caused by the diagnosis and treatment of CDI infection and its complications. Studies indicate that the nosocomial infection of C. difficile complicates hospitalisation, by increasing the cost by more than half and extending patient’s stay by an average of 3.6 days. Material and methods: The aim of this study was to attempt to calculate the estimated costs associated with the prolonged hospitalisation of patients with nosocomial CDI infection, using the example of a hospital in Lodz. A total of 53 completed hospitalisations of patients treated in the period of January–August 2018 were analysed, during which hospital Clostridioides difficile infection was identified. For the purposes of this study, statistical data collected in the hospital’s IT system were also analysed, covering 44,868 hospitalisations in the Jan–Aug 2018 period, during which no hospital infection occurred. They was a control group, in which the analysed cases were compared. The obtained data in the study determined how long each patient with Clostridioides difficile infection stayed in the hospital (from the moment infection was diagnosed until the day of hospital discharge), and which diagnosis related groups (DRG) (according to National Health Fund guidelines) were assigned. The average length of patient stay without infection within a given DRG group in each hospital ward was also determined. The collected materials became the initial point for the final analysis of hospital costs and the length of hospital stay caused by Clostridioides difficile infection. Results: Clostridioides difficile infection extended the hospital stay by an average of almost 12 days. The average cost of prolonged hospitalisation due to CDI infection (according to the average cost per person-day) was about PLN 7148 (1664 EUR), which gave a total value of about PLN 378,860.6 (88,240.5 EUR) in the examined period. At the same time, the average expenditure from the National Health Fund for hospitalisation due to CDI infections increased by about PLN 6627 (1542.8 EUR), which in the analysed period translated into over PLN 351,232.0 (81,505.5 EUR) (according to settlements with the National Health Fund). The outcome indicates that there is a clear relation between CDI and the anticipated length of hospitalisation of patients without an infection.

Bioinformatics-driven discovery of novel Clostridioides difficile lysins and experimental comparison with highly active benchmarks

Clostridioides difficile is the single most deadly bacterial pathogen in the United States, and its global prevalence and outsized health impacts underscore the need for more effective therapeutic options. Towards this goal, a novel group of modified peptidoglycan hydrolases with significant in vitro bactericidal activity have emerged as potential candidates for treating C. difficile infections (CDI). To date, discovery and development efforts directed at these CDI-specific lysins have been limited, and in particular there has been no systematic comparison of known or newly discovered lysin candidates. Here, we detail bioinformatics-driven discovery of six new anti-C. difficile lysins belonging to the amidase-3 family of enzymes, and we describe experimental comparison of their respective catalytic domains (CATs) with highly active CATs from the literature. Our quantitative analyses include metrics for expression level, inherent antibacterial activity, breadth of strain selectivity, killing of germinating spores, and structural and functional measures of thermal stability. Importantly, prior studies have not examined stability as a performance metric, and our results show that the panel of eight enzymes possess widely variable thermal denaturation temperatures and resistance to heat inactivation, including some enzymes that exhibit marginal stability at body temperature. Ultimately, no single enzyme dominated with respect to all performance measures, suggesting the need for a balanced assessment of lysin properties during efforts to find, engineer, and develop candidates with true clinical potential.

Epidemiology of community-acquired and recurrent Clostridioides difficile infection

Clostridioides difficile infection is a leading cause of healthcare-associated infections with significant morbidity and mortality. For the past decade, the bulk of infection prevention and epidemiologic surveillance efforts have been directed toward mitigating hospital-acquired C. difficile. However, the incidence of community-associated infection is on the rise. Patients with community-associated C. difficile tend to be younger and have lower mortality rate. Rates of recurrent C. difficile infection overall have decreased in the United States, but future research and public health endeavors are needed to standardize and improve disease detection, stratify risk factors in large-scale population studies, and to identify regional and local variations in strain types, reservoirs and transmission routes to help characterize and combat the changing epidemiology of C. difficile.

Complete genome sequence of the newly discovered temperate Clostridioides difficile bacteriophage phiCDKH01 of the family Siphoviridae

A temperate siphovirus, phiCDKH01, was obtained from a clinical isolate of Clostridioides difficile. The phage genome is a 45,089-bp linear double-stranded DNA molecule with an average G+C content of 28.7%. It shows low similarity to known phage genomes, except for phiCD24-1. Genomic and phylogenetic analysis revealed that phiCDKH01 is a newly discovered phage. Sixty-six putative ORFs were predicted in the genome, 37 of which code for proteins with predicted functions. The phiCDKH01 prophage was localized in the host genome. The results of this study increase our knowledge about the genetic diversity of tailed phages.

Higher genome variability within metabolism genes associates with recurrent Clostridium difficile infection

BACKGROUND

Clostridium difficile (C. difficile) is a major source of healthcare-associated infection with a high risk of recurrence, attributable to many factors such as usage of antibiotics, older age and immunocompromised status of the patients. C. difficile has also a highly diverse genome, which may contribute to its high virulence. Herein we examined whether the genome conservation, measured as non-synonymous to synonymous mutations ratio (dN/dS) in core genes, presence of single genes, plasmids and prophages increased the risk of reinfection in a subset of 134 C. difficile isolates from our previous study in a singly hemato-oncology ward.

METHODS

C. difficile isolates were subjected to whole-genome sequencing (WGS) on Ion Torrent PGM sequencer. Genomes were assembled with MIRA5 and annotated with prokka and VRprofile. Logistic regression was used to asses the relationship between single gene presence and the odds of infection recurrence. DN/dS ratios were computed with codeml. Functional annotation was conducted with eggNOG-Mapper.

RESULTS

We have found that the presence of certain genes, associated with carbon metabolism and oxidative phosphorylation, increased the odds of infection recurrence. More core genes were under positive selective pressure in recurrent disease isolates - they were mostly associated with the metabolism of aminoacids. Finally, prophage elements were more prevalent in single infection isolates and plasmids did not influence the odds of recurrence.

CONCLUSIONS

Our findings suggest higher genetic plasticity in isolates causing recurrent infection, associated mainly with metabolism. On the other hand, the presence of prophages seems to reduce the isolates' virulence.

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

Clostridioides difficile is the most common cause of healthcare-associated diarrhea. Disease complications as well as recurrent infections contribute significantly to morbidity and mortality. Over the past decades, there has been a rapid increase in the incidence of C. difficile infection (CDI), with a rise in the number of community-acquired cases. CDI has a profound economic impact on both the healthcare system and patients, secondary to recurrences, hospitalization, prolonged length of stay, cost of treatment, and indirect societal costs. With emergence of newer treatment options, the standard of care is shifting from metronidazole and vancomycin towards fidaxomicin and fecal microbiota transplantation (FMT), which despite being more expensive, are more efficacious in preventing recurrences and hence overall are more beneficial forms of therapy per cost-effectiveness analyses. Data regarding preferred route of FMT, timing of FMT, and non-conventional therapies such as bezlotoxumab is scant. There is a need for further studies to elucidate the true attributable costs of CDI as well as continued cost-effectiveness research to reduce the economic burden associated with the disease and improve clinical practice.

The impact of intensive staff education on rate of Clostridium difficile-associated disease in hospitalized geriatric patients

BACKGROUND

Toxin-producing Clostridium difficile is the most common cause of nosocomial diarrhea in geriatric units.

AIM

The purpose of study was to check the impact of intensive staff education on rate of Clostridium difficile-associated disease in hospitalized geriatric patients.

METHODS

The sampling frame was all patients suffering from diarrhea checked for Clostridium difficile toxin during the years 2017-2018. Clostridium difficile-positive patients were compared to a similar number of Clostridium difficile toxin-negative patients. The data were compared to our previous study, followed by medical staff's educational program for Clostridium difficile control and prevention.

RESULTS

Among 217 patients with diarrhea, 60 (27.6%) were positive for Clostridium difficile toxin. The study group tended to be of older age (p = 0.06), and showed higher rate of functional impairment (p < 0.001) and mortality (p < 0.001) than Clostridium difficile toxin negative patients. The rate of Clostridium difficile toxin-positive patients did not significantly differ between the previous and current studies (20.0% and 27.6%, respectively).

CONCLUSIONS AND DISCUSSION

In spite of findings, that patients tended to be older, with high rate of mortality, the rate of Clostridium difficile did not change from the previous study.

Safety, immunogenicity, and efficacy of a Clostridioides difficile toxoid vaccine candidate: a phase 3 multicentre, observer-blind, randomised, controlled trial

BACKGROUND

In the absence of a licensed vaccine, Clostridioides (formerly Clostridium) difficile infection represents a substantial health burden. The aim of this study was to evaluate the efficacy, immunogenicity, and safety of a toxoid vaccine candidate.

METHODS

We did a phase 3 multicentre, observer-blind, randomised, controlled trial at 326 hospitals, clinics, and clinical research centres in 27 countries in the USA, Canada, Latin America, Europe, and the Asia-Pacific region. We included adults aged 50 years or older who were considered to be at an increased risk of C difficile infection because they had previously had two hospital stays (each ≥24 h in duration) and had received systemic antibiotics in the previous 12 months (risk stratum 1), or because they were anticipating being admitted to hospital for 72 h or more for elective surgery within 60 days of enrolment (risk stratum 2). Eligible participants were stratified by geographical region and the two risk strata, and randomly assigned (2:1), with a fixed block size of three, to receive either a C difficile toxoid vaccine candidate, containing toxoids A and B (C difficile vaccine candidate group), or a placebo vaccine (placebo group). Participants, investigators, and personnel responsible for collecting safety data and analysing blood and stool samples were masked to group assignment. Personnel responsible for study product preparation and administration were not masked to group assignment. One dose (0·5 mL) of C difficile vaccine candidate or placebo vaccine was administered intramuscularly on days 0, 7, and 30. The primary outcome was the efficacy of the vaccine in preventing symptomatic C difficile infection, defined as having three or more loose stools in a period of 24 h or less, loose stools for 24 h or more, and a PCR-positive test for C difficile toxin B in a loose stool sample, within 3 years after the final vaccine dose. The primary outcome was measured in the modified intention-to-treat population (ie, all participants who received at least one injection of the assigned vaccine). The safety of the vaccine was assessed in the safety analysis set (ie, all participants who had received at least one injection, analysed according to the product received). This study is registered with WHO/ICTRP, number U111-1127-7162, and ClinicalTrials.gov, number NCT01887912, and has been terminated.

FINDINGS

Between July 30, 2013, and Nov 17, 2017, we enrolled and randomly assigned 9302 participants to the C difficile vaccine candidate group (n=6201) or to the placebo group (n=3101). 6173 (99·5%) participants in the C difficile vaccine candidate group and 3085 (99·5%) participants in the placebo group received at least one dose of the vaccine. The study was terminated after the first planned interim analysis because of futility. In the C difficile vaccine candidate group, 34 C difficile infections were reported over 11 697·2 person-years at risk (0·29 infections per 100 person-years [95% CI 0·20-0·41]) compared with 16 C difficile infections over 5789·4 person-years at risk in the placebo group (0·28 infections per 100 person-years [0·16-0·45]), indicating a vaccine efficacy of -5·2% (95% CI -104·1 to 43·5). In the C difficile vaccine candidate group, 2847 (46·6%) of 6113 participants reported an adverse event within 30 days of injection compared with 1282 (41·9%) of 3057 participants in the placebo group. The proportion of participants who had an adverse event leading to study discontinuation was 4·8% in both groups (296 participants in the C difficile vaccine candidate group and 146 participants in the placebo group). 1662 (27·2%) participants in the C difficile vaccine candidate group reported at least one serious adverse event compared with 851 (27·8%) participants in the placebo group.

INTERPRETATION

In adults at risk for C difficile infection, a bivalent C difficile toxoid vaccine did not prevent C difficile infection. Since the C difficile vaccine candidate met the criteria for futility, the study was terminated and clinical development of this vaccine candidate was stopped.

FUNDING

Sanofi Pasteur.

Fecal Microbiota Transplantation for Recurrent Clostridium difficile Infection in Patients With Multiple Comorbidities: Long-Term Safety and Efficacy Results From a Tertiary Care Community Hospital

Background

Cure rates of Clostridium difficile infection (CDI) with fecal microbiota transplant (FMT) have been promising. However, there is debate regarding success of FMT in patients with comorbidities.

Methods

Electronic chart review was done to collect data on patients who underwent FMT from January 2015 to August 2017. Charts were analyzed in November 2018 with a median follow-up of 25.4 months (interquartile range 20 - 31 months).

Results

Twenty patients underwent FMT. The primary success rate at our institution was 90% and overall success rate was 100%. Six patients (43%) had FMT failure (two early and four late).

Conclusions

This case series is a description of our center’s initial experience with FMT for treatment of recurrent CDI. Our high success rate reiterates the efficacy and safety of FMT in this population including patients with comorbidities.

Predictive Factors for the First Recurrence of Clostridioides difficile Infection in the Elderly from Western Romania

Background and objectives: At present, Romania and parts of the European Union are facing an increasingly challenging public health problem consisting of nosocomial Clostridioides difficile infection (CDI), mostly in the elderly. Relapse cases have become more frequent, which present higher morbidity and mortality rates than the initial CDI infection. The aim of this study is to determine the predictive factors for recurrence, with the purpose of reducing the exposure of patients diagnosed with CDI, as well as aiming to initiate early treatment. Materials and Methods: In this retrospective descriptive study, we analyze a database from the First Department of Infectious Diseases at the Dr. Victor Babes Clinical Hospital for Infectious Diseases and Pulmonology in Timisoara, looking for patient history of CDI recurrences. We analyzed CDI recurrence in patients aged ≥65 years from 1 January 2016 to 31 December 2019, identifying 77 cases of CDI recurrence. The determination of predictive factors for recurrence involved the formation of a randomized control group, consisting of 74 patients aged ≥65 years who were diagnosed with C. difficile enterocolitis, but did not suffer a recurrence and survived ≥2 weeks after symptom onset. Results: Immunocompromised status, pre-existing gastrointestinal disease, and fever on initial hospitalization for CDI were all found to be significant independent positive predictive factors for the condition recurring in elderly Romanian patients. Conclusions: As the geriatric population in Romania grows, the national health system becomes increasingly overburdened, both from a financial standpoint and a human resources perspective. The analysis of factors predictive for CDI recurrence is, thus, of the utmost importance, particularly for the early identification of patients most at risk of CDI recurrence. Our findings could help physicians to identify recurrence early, consequently benefitting patients by a rapid intervention with a potential decrease in the associated complications and mortality.

Clinical characteristics and prognostic factors of extraintestinal infection caused by Clostridioides difficile: analysis of 60 consecutive cases

Data regarding extraintestinal Clostridioides difficile infections (ECDIs) remain scarce and anecdotal. We conducted a retrospective cohort study to investigate characteristics and prognostic factors in patients with ECDI. From January 1997 through December 2018, 60 patients were enrolled and divided into three groups as follows: group A (gastrointestinal [GI] disruption caused by malignancy, n = 13); group B (GI disruption from causes other than malignancy, n = 25); group C (no GI disruption, n = 22). GI disruption was defined as compromised integrity of the GI tract caused by abdominal surgery, perforation, malignancy, enterocolitis, or bleeding. The incidence of ECDI was 2.53 per 100,000 admissions. The most common specimens yielded C. difficile were blood (36.7%), peritoneal fluid (20.0%), and abscesses (16.7%). Six patients (10.0%) had confirmed C. difficile enterocolitis, and 36 patients (60.0%) had a polymicrobial infection. C. difficile bacteremia was significantly more common in group A patients than those in groups B or C (53.8% vs. 48.0% vs. 13.6%, p = 0.02), as was the 30-day mortality rate (69.2% vs. 12.0% vs. 18.2%, respectively; p < 0.001). In multivariate analysis, group A (adjusted odds ratio [aOR], 17.32; 95% confidence interval [CI], 2.96-101.21; p = 0.002) and an age of > 65 years (aOR, 7.09; 95% CI, 1.31-38.45; p = 0.02) were independent risk factors for 30-day mortality. ECDI was uncommonly associated with C. difficile enterocolitis. Two factors, GI disruption caused by malignancy, and old age, were associated with significantly poorer short-term outcomes.

Early Surgical Intervention for Fulminant Pseudomembranous Colitis

The objective of this study of a retrospective case series was to determine factors associated with survival after surgical intervention in pseudomembranous colitis (PMC). The study was conducted at a tertiary care medical center and comprised 36 patients who underwent colectomy for fulminant PMC from 1995 to 2006. Patients including 21 females ranged from 40 to 89 years of age (mean, 70 years). Comorbidities included diabetes (39%), cardiovascular disease (77%), chronic obstructive pulmonary disease (47%), and intake of immunosuppressive medications (45%). Seventy-two per cent received antibiotics in the previous 2 months. Only patients with a confirmation of PMC on pathology specimens were included in the study. All patients underwent colectomy. Patients were stratified into two groups: survivors and nonsurvivors. Various clinical factors/parameters used in the management of patients with PMC were studied in these two groups. Survival was correlated with mean white blood cell count (23,000 survivors versus 40,000 nonsurvivors, P < 0.01); multisystem organ failure (16 per cent survivors versus 47 per cent nonsurvivors, P < 0.05); and preoperative pressors (16 per cent survivors versus 47 per cent nonsurvivors, P < 0.05). Overall mortality for the study period was 47 per cent. Mortality rate analysis revealed a lower rate for the more recent years (32 per cent for 2000 to 2006 versus 65 per cent for 1995 to 1999, P < 0.05). In the more recent years, the time elapsing before colectomy was also lower (1.4 days versus 2.5 days, nonsignificant), and patients had less preoperative hemodynamic instability (70 per cent versus 31 per cent, P < 0.03). In one institution, survival after surgery for PMC was found to be associated with a mean white blood cell count (<37,000), nondependence on preoperative vasopressors, and surgical intervention before the onset of hemodynamic instability.

Salicylanilide Analog Minimizes Relapse of Clostridioides difficile Infection in Mice

Clostridioides difficile infection (CDI) causes serious and sometimes fatal symptoms like diarrhea and pseudomembranous colitis. Although antibiotics for CDI exist, they are either expensive or cause recurrence of the infection due to their altering the colonic microbiota, which is necessary to suppress the infection. Here, we leverage a class of known membrane-targeting compounds that we previously showed to have broad inhibitory activity across multiple Clostridioides difficile strains while preserving the microbiome to develop an efficacious agent. A new series of salicylanilides was synthesized, and the most potent analog was selected through an in vitro inhibitory assay to evaluate its pharmacokinetic parameters and potency in a CDI mouse model. The results revealed reduced recurrence of CDI and diminished disturbance of the microbiota in mice compared to standard-of-care vancomycin, thus paving the way for novel therapy that can potentially target the cell membrane of C. difficile to minimize relapse in the recovering patient.

Fecal microbiota transplantation for patients on antibiotic treatment with C. difficile infection history (GRAFT): Study protocol for a phase II, randomized, double-blind, placebo-controlled trial to prevent recurrent C. difficile infections

Recurrent Clostridiodes difficile infections (rCDIs) are a burdensome problem. Patients with a history of CDI that are prescribed antibiotics are at a high risk for recurrence. Fecal microbiota transplantation (FMT) has been shown to be an effective treatment for rCDI, though there is little information on the impact of FMT with antibiotics on the gut microbiome. We are conducting a clinical trial of FMT to prevent rCDI in patients with a history of CDI currently taking antibiotics. Our primary objective is to determine the effect of FMT on the gut microbiome during antibiotic exposure. Our secondary aim is to assess safety and feasibility of using FMT as a prophylaxis for CDI. We plan to enroll 30 patients into a phase II randomized, double-blind, placebo-controlled trial with three arms: (1) 5 FMT capsules per day during antibiotic treatment and for 7 days post antibiotic cessation, (2) a one-time dose of 30 FMT capsules 48–72 h post cessation of antibiotic treatment, or (3) 5 placebo capsules per day during antibiotic treatment and for 7 days post antibiotic treatment. Patients provide stool samples throughout the duration of the study and are cultured C. difficile. Sequencing of the V4 region of the 16S rRNA gene will be carried out to assess the gut microbiota. Results of this study will provide information on the impact of FMT on the gut microbiome as well as the necessary data to examine whether or not prophylactic FMT should be explored further as a way to prevent CDI recurrence.

Bacteriophage-mediated manipulation of the gut microbiome – promises and presents limitations

Gut microbiome (GM) composition and function are linked to human health and disease, and routes for manipulating the GM have become an area of intense research. Due to its high treatment efficacy, the use of fecal microbiota transplantation (FMT) is generally accepted as a promising experimental treatment for patients suffering from GM imbalances (dysbiosis), e.g. caused by recurrent Clostridioides difficile infections (rCDI). Mounting evidence suggests that bacteriophages (phages) play a key role in successful FMT treatment by restoring the dysbiotic bacterial GM. As a refinement to FMT, removing the bacterial component of donor feces by sterile filtration, also referred to as fecal virome transplantation (FVT), decreases the risk of invasive infections caused by bacteria. However, eukaryotic viruses and prophage-encoded virulence factors remain a safety issue. Recent in vivo studies show how cascading effects are initiated when phage communities are transferred to the gut by e.g. FVT, which leads to changes in the GM composition, host metabolome, and improve host health such as alleviating symptoms of obesity and type-2-diabetes (T2D). In this review, we discuss the promises and limitations of FVT along with the perspectives of using FVT to treat various diseases associated with GM dysbiosis.

Growing consumption of antibiotics and epidemiology of Clostridioides difficile infections in Poland: A need to develop new solutions

Clostridioides (formerly Clostridium) difficile infections (CDIs) are becoming more common and more serious. C. difficile is the etiologic agent of antibiotic-associated diarrhea, pseudomembranous enterocolitis, and toxic megacolon while CDIs recur in 7.9% of patients. About 42.9 CDI cases/10,000 patient-days are diagnosed each day in Europe, whereas in Poland 5.6 CDI cases/10,000 patient-days are reported; however, the median for European countries is 2.9 CDI cases/10,000 patient-days. Epidemiology of CDIs has changed in recent years and risk of developing the disease has doubled in the past decade that is largely determined by use of antibiotics. Studies show that rate of antibiotic consumption in the non-hospital sector in Poland is much higher than the European average (27 vs. 21.8 DDD/1,000 patient-days), and this value has increased in recent years. Antibiotic consumption has also increased in the hospital sector, especially in the intensive care units - 1,520 DDD/1,000 patient-days (ranging from 620 to 3,960 DDD/1,000 patient-days) - and was significantly higher than in Germany 1,305 (ranging from 463 to 2,216 DDD/1,000 patient-days) or in Sweden 1,147 (ranging from 605 to 2,134 DDD/1,000 patient-days). The recent rise in CDI incidence has prompted a search for alternative treatments. Great hope is placed in probiotics, bacteriocins, monoclonal antibodies, bacteriophages, and developing new vaccines.

Long-Term Antibiotic Prophylaxis in Urology and High Incidence of Clostridioides difficile Infections in Surgical Adult Patients

Clostridioides difficile infections are the main cause of antibiotic-related diarrhea. Most of them come in the form of healthcare-associated Clostridioides difficile infections (HA-CDI). The aim of the study was to analyze HA-CDI epidemiology and the relationship between antibiotic consumption and CDI epidemiology at St Luke’s Provincial Hospital in Tarnow, Poland. In 2012–2018, surveillance of CDI was carried out in adult surgical wards at St Luke’s Provincial Hospital. The data were collected in accordance with the methodology of the Healthcare-Associated Infections Surveillance Network (HAI-Net), European Centre for Disease Prevention and Control (ECDC), and the ATC/DDD system (Anatomical Therapeutic Chemical Classification System) of the World Health Organization. In total, in the study period, 51 cases of CDI involved CA-CDI (24.5%) and 147 were HA-CDIs (75.5%). The most CA-CDIs were found in the general surgery (32.6%) and urology (17.0%) wards. CA-CDI incidence was 0.7/1000 patients and for HA-CDI it was 2/1000 patients (4.4/10,000 patientdays (pds)). The highest HA-CDI incidence was in the neurosurgical departments (18/10,000 pds) and oncological surgery (8.4/10,000) pds. There was a significant positive correlation between CA-CDI and HA-CDI (correlation of 0.943, p < 0.001) and between the number of patients hospitalized and HA-CDI (correlation of 0.865, p = 0.012). The total antibiotic consumption amounted to 0.7 DDD/10,000 pds; it was the highest in the urology ward (0.84/10,000 pds) and 49.5% of the antibiotics were fluoroquinolones (0.41/10,000 pds). On the basis of regression coefficients, a positive correlation was demonstrated between the use of fluoroquinolones and the HA-CDI incidence rate. Both a high percentage of CDI cases and a high intake of antibiotics were recorded in the urology department. About half of all antibiotics were fluoroquinolones.

Recommendations for the diagnosis and treatment of Clostridioides difficile infection: An official clinical practice guideline of the Spanish Society of Chemotherapy (SEQ), Spanish Society of Internal Medicine (SEMI) and the working group of Postoperative Infection of the Spanish Society of Anesthesia and Reanimation (SEDAR)

This document gathers the opinion of a multidisciplinary forum of experts on different aspects of the diagnosis and treatment of Clostridioides difficile infection (CDI) in Spain. It has been structured around a series of questions that the attendees considered relevant and in which a consensus opinion was reached. The main messages were as follows: CDI should be suspected in patients older than 2 years of age in the presence of diarrhea, paralytic ileus and unexplained leukocytosis, even in the absence of classical risk factors. With a few exceptions, a single stool sample is sufficient for diagnosis, which can be sent to the laboratory with or without transportation media for enteropathogenic bacteria. In the absence of diarrhoea, rectal swabs may be valid. The microbiology laboratory should include C. difficile among the pathogens routinely searched in patients with diarrhoea. Laboratory tests in different order and sequence schemes include GDH detection, presence of toxins, molecular tests and toxigenic culture. Immediate determination of sensitivity to drugs such as vancomycin, metronidazole or fidaxomycin is not required. The evolution of toxin persistence is not a suitable test for follow up. Laboratory diagnosis of CDI should be rapid and results reported and interpreted to clinicians immediately. In addition to the basic support of all diarrheic episodes, CDI treatment requires the suppression of antiperistaltic agents, proton pump inhibitors and antibiotics, where possible. Oral vancomycin and fidaxomycin are the antibacterials of choice in treatment, intravenous metronidazole being restricted for patients in whom the presence of the above drugs in the intestinal lumen cannot be assured. Fecal material transplantation is the treatment of choice for patients with multiple recurrences but uncertainties persist regarding its standardization and safety. Bezlotoxumab is a monoclonal antibody to C. difficile toxin B that should be administered to patients at high risk of recurrence. Surgery is becoming less and less necessary and prevention with vaccines is under research. Probiotics have so far not been shown to be therapeutically or preventively effective. The therapeutic strategy should be based, rather than on the number of episodes, on the severity of the episodes and on their potential to recur. Some data point to the efficacy of oral vancomycin prophylaxis in patients who reccur CDI when systemic antibiotics are required again.

Bacteriocins From LAB and Other Alternative Approaches for the Control of Clostridium and Clostridiodes Related Gastrointestinal Colitis

The gut microbiome is considered as a promising target for future non-conventional therapeutic treatment of inflammatory and infectious diseases. The search for appropriate safe and beneficial (lactic acid bacterial and other) putative probiotic strains and/or their antimicrobial metabolites represents a challenging approach for combating several problematic and emerging infections. The process of selecting suitable strains, especially of lactic acid bacteria (LAB) with superior properties, has been accelerated and intensified during the past two decades, also thanks to recent developments in lab techniques. Currently, special focus is on the potential of antimicrobial metabolites produced by some LAB strains and their application as active therapeutic agents. The vision is to develop a scientific basis for 'biotherapeutics' as alternative to conventional approaches in both human and veterinary medicine. Consequently, innovative and promising applications of LAB to the therapeutic practice are presently emerging. An overview of the existing literature indicates that some antimicrobial metabolites such as bacteriocins, widely produced by different bacterial species including LAB, are promising biotherapeutic agents for controlling infections caused by potential pathogens, such as Clostridium and Clostridiodes. Non-conventional, safe and well designed therapeutic treatments may contribute to the improvement of gut dysbiotic conditions. Thereby gut homeostasis can be restored and inflammatory conditions such as gastrointestinal colitis ameliorated. Combining the knowledge on the production, characterization and application of bacteriocins from probiotic LAB, together with their antibacterial properties, appears to be a promising and novel approach in biotherapy. In this overview, different scenarios for the control of Clostridium spp. by application of bacteriocins as therapeutic agents, also in synergistic combination with antibiotics, will be discussed.

Predictors of Clostridioides difficile recurrence across a national cohort of veterans in outpatient, acute, and long-term care settings

PURPOSE

The greatest challenge in treating Clostridioides difficile infection (CDI) is disease recurrence, which occurs in about 20% of patients, usually within 30 days of treatment cessation. We sought to identify independent predictors of first recurrence among a national cohort of veterans with CDI.

METHODS

We conducted a case-control study among acute and long-term care Veterans Affairs (VA) inpatients and outpatients with a first CDI episode (positive stool sample for C. difficile toxin[s] and receipt of at least 2 days of CDI treatment) between 2010 and 2014. Cases experienced first recurrence within 30 days from the end of treatment. Controls were those without first recurrence matched 4:1 to cases on year, facility, and severity. Multivariable conditional logistic regression was used to identify predictors of first recurrence.

RESULTS

We identified 32 predictors of first recurrence among 974 cases and 3,896 matched controls. Significant predictors included medication use prior to (probiotics, fluoroquinolones, laxatives, third- or fourth-generation cephalosporins), during (first- or second-generation cephalosporins, penicillin/amoxicillin/ampicillin, third- and fourth-generation cephalosporins), and after CDI treatment (probiotics, any antibiotic, proton pump inhibitors [PPIs], and immunosuppressants). Other predictors included current biliary tract disease, malaise/fatigue, cellulitis/abscess, solid organ cancer, medical history of HIV, multiple myeloma, abdominal pain, and ulcerative colitis.

CONCLUSION

In a large national cohort of outpatient and acute and long-term care inpatients, treatment with certain antibiotics, PPIs, immunosuppressants, and underlying disease were among the most important risk factors for first CDI recurrence.

Virulence Factors of Clostridioides (Clostridium) difficile Linked to Recurrent Infections

From 20 to 30% of Clostridioides (Clostridium) difficile infection (CDI), patients might develop recurrence of the infection (RCDI) and, after the first recurrence, the risk of further episodes increases up to 60%. Several bacterial virulence factors have been associated with RCDI, including the elevated production of toxins A and B, the presence of a binary toxin CDT, and mutations in the negative regulator of toxin expression, tcdC. Additional factors have shown to regulate toxin production and virulence in C. difficile in RCDI, including the accessory-gene regulator agr, which acts as a positive switch for toxin transcription. Furthermore, adhesion and motility-associated factors, such as Cwp84, SlpA, and flagella, have shown to increase the adhesion efficiency to host epithelia, cell internalization, and the formation of biofilm. Finally, biofilm confers to C. difficile protection from antibiotics and acts as a reservoir for spores that allow the persistence of the infection in the host. In this review, we describe the key virulence factors of C. difficile that have been associated with recurrent infections.

Synthetic Oligosaccharide-Based Vaccines Protect Mice from Clostridioides difficile Infections

Infections with Clostridioides difficile (formerly Clostridium difficile) have increased in incidence, morbidity, and mortality over the past decade. Preventing infections is becoming increasingly important, as frontline antibiotics become less effective and frequently induce recurrence by disrupting intestinal microbiota. The clinically most advanced vaccine approaches prevent symptoms once C. difficile infection is established by inducing immunity to secreted clostridial cytotoxins. However, they do not inhibit bacterial colonization and thereby favor asymptomatic carriage. Synthetic oligosaccharides resembling the C. difficile surface glycans PS-I, PS-II, and PS-III are immunogenic and serve as basis for colonization-preventing vaccines. Here, we demonstrate that glycoconjugate vaccine candidates based on synthetic oligosaccharides protected mice from infections with two different C. difficile strains. Four synthetic antigens, ranging in size from disaccharides to hexasaccharides, were conjugated to CRM₁₉₇, which is a carrier protein used in commercial vaccines. The vaccine candidates induced glycan-specific antibodies in mice and substantially limited C. difficile colonization and colitis after experimental infection. The glycoconjugates ameliorated intestinal pathology more substantially than a toxin-targeting vaccine. Colonization of the gut by C. difficile was selectively inhibited while intestinal microbiota remained preserved. Passive transfer experiments with anti-PS-I serum revealed that protection is mediated by specific antiglycan antibodies; however, cell-mediated immunity likely also contributed to protection in vivo. Thus, glycoconjugate vaccines against C. difficile are a complementary approach to toxin-targeting strategies and are advancing through preclinical work.

The current novel therapeutic regimens for Clostridium difficile infection (CDI) and the potentials of Traditional Chinese Medicine in treatment of CDI

Clostridium difficile infection (CDI) is featured as the dysbiosis of gut microbiota and consequent mild diarrhoea or severe pseudomembranous colitis. However, the frequent recurrence of CDI following treatment course challenged the antibiotic therapy. Currently, to address the relapse of CDI, several novel therapeutic approaches have emerged, including Bezlotoxumab, SYN-004 (Ribaxamase), RBX2660, and faecal microbial transplant. Traditional Chinese Medicine (TCM) is an old medical system accumulated for thousands of years. Orientated by syndrome-based treatment, TCM functions in a multicomponent and multitarget mode. This old medical system showed superiority over conventional medical treatment, particularly in the treatment of complex disorders, including CDI. In the present review, we will elaborate the TCM intervention in the management of CDI and others disorders via restoring the gut microbiota dysbiosis. We hope that this review will deepen our understanding of TCM as an alternative to CDI treatment. However, more rigorously designed basic researches and randomised controlled trials need to conduct to appraise the function mechanisms and effects of TCM. Finally, it is concluded that the combined therapeutic potentials of TCM and western medicine could be harness to resolve the recurrence and improve the outcome of CDI.

Incidence of and risk factors for recurrent Clostridioidesdifficile infection in Japan using a claims database: A retrospective cohort study

This retrospective cohort study aimed to determine the incidence rates of and risk factors for recurrent Clostridioides difficile infection (rCDI) in Japan using a claims database. Inpatients of any age with ≥1 record of C. difficile infection (CDI) during the study period (January 2012-September 2016) were analyzed. We estimated the incidence rate of health care onset, health care facility associated (HO-HCFA) primary CDI and HO-HCFA rCDI for each of the first to fifth recurrences. Risk factors for the first recurrence were investigated using a univariate, and subsequently, a multivariable Cox regression model. The incidence rates (95% confidence interval [CI]) of CDI and HO-HCFA CDI were 2.43 (2.40-2.46) and 1.26 (1.24-1.28) cases per 10,000 inpatient-days, respectively. Among the 11,287 inpatients with ≥1 HO-HCFA CDI, 1424 patients had ≥1 recurrent episode (12.6% [95% CI 12.0-13.2]). The rCDI incidence rates consistently increased, with the number of recurrences ranging from 29.2 to 181.8 cases per 10,000 inpatient-days. The multivariable analysis revealed five risk factors (hazard ratio [95% CI]): age ≥65 years (vs. <65 years; 65-74 years, 1.275 [1.048-1.551]; 75-79 years, 1.612 [1.315-1.975]; ≥80 years, 2.110 [1.776-2.507]); cephalosporin use both before (vs. without cephalosporin; 1.241 [1.098-1.402]) and during the primary CDI (vs. without cephalosporin; 1.137 [1.011-1.279]); higher number of comorbidities (vs. ≤10 comorbidities; 11-14 comorbidities: 1.336 [1.131-1.580]; 15-20 comorbidities: 1.433 [1.219-1.685]; ≥21 comorbidities: 1.310 [1.099-1.561]); and gastrointestinal surgery (vs. without surgery; 0.823 [0.701-0.965]). In conclusion, CDI recurred in some Japanese patients, and the incidence rates increased with the number of recurrences. Special care is needed in patients aged ≥65 years, those with a higher number (>10) of comorbidities, and those who have received cephalosporin before or during the primary CDI.

Cost-effectiveness of Bezlotoxumab Compared With Placebo for the Prevention of Recurrent Clostridium difficile Infection

Background

Clostridium difficile infection (CDI) is the most commonly recognized cause of recurrent diarrhea. Bezlotoxumab, administered concurrently with antibiotics directed against C. difficile (standard of care [SoC]), has been shown to reduce the recurrence of CDI, compared with SoC alone. This study aimed to assess the cost-effectiveness of bezlotoxumab administered concurrently with SoC, compared with SoC alone, in subgroups of patients at risk of recurrence of CDI.

Methods

A computer-based Markov health state transition model was designed to track the natural history of patients infected with CDI. A cohort of patients entered the model with either a mild/moderate or severe CDI episode, and were treated with SoC antibiotics together with either bezlotoxumab or placebo. The cohort was followed over a lifetime horizon, and costs and utilities for the various health states were used to estimate incremental cost-effectiveness ratios (ICERs). Both deterministic and probabilistic sensitivity analyses were used to test the robustness of the results.

Results

The cost-effectiveness model showed that, compared with placebo, bezlotoxumab was associated with 0.12 quality-adjusted life-years (QALYs) gained and was cost-effective in preventing CDI recurrences in the entire trial population, with an ICER of $19824/QALY gained. Compared with placebo, bezlotoxumab was also cost-effective in the subgroups of patients aged ≥65 years (ICER of $15298/QALY), immunocompromised patients (ICER of $12597/QALY), and patients with severe CDI (ICER of $21430/QALY).

Conclusions

Model-based results demonstrated that bezlotoxumab was cost-effective in the prevention of recurrent CDI compared with placebo, among patients receiving SoC antibiotics for treatment of CDI.

Reducing Cost and Complexity of Fecal Microbiota Transplantation Using Universal Donors for Recurrent Clostridium difficile Infection

Introduction

Fecal microbiota transplantation resolves recurrent Clostridium difficile infections in greater than 82% of patients. Highly screened, processed universal donor fecal material is available. We compared cost and scheduling efficiency of fecal microbiota transplantation by universal donors to patient-directed donors.

Methods

Medical records from a prospectively maintained database of recurrent C. difficile patients who underwent fecal microbiota transplantation between 2012 and 2017 were reviewed retrospectively. Patient-directed donor stool was prepared in our microbiology laboratory using protocol-based screening. We transitioned to purchasing and using universal donor fecal material in 2015. Clinical outcomes, adverse events, time between consult to infusion, consultation fees, and material costs were compared. This was a retrospective comparison of two historical cohorts.

Results

A total of 111 fecal microbiota transplantations were performed on 105 patients (56 from patient-directed donors and 55 from universal donors). Median recipient age was 66 years (18–96) with male to female ratio of 1:2.7, equivalent in both cohorts. Total consultation fees were significantly lower in the universal donor group owing to fewer infectious disease consultations. Costs for donor screening and stool preparation were lower in the universal donor cohort ($485.0 vs. $1189.90 ± 541.4, p < 0.001, 95% CI 559.9–849.9). Time from consultations to infusion was shorter in the universal donor cohort (18.9 ± 19.1 vs. 36.4 ± 23.3 days, p < 0.001, 95% CI 9.521–25.591). Recurrences within 8 weeks after fecal microbiota transplantation were equivalent (p = 0.354). Adverse events were equivalent.

Conclusions

Fecal microbiota transplantation using universal donors versus patient-directed donors for recurrent C. difficile showed comparable efficacy and short-term complications. The use of universal donors resulted in significant cost savings and scheduling efficiency.

The human microbiome in health and disease: hype or hope

OBJECTIVES

The prognostic, diagnostic, and therapeutic potential of the human gut microbiota is widely recognised. However, translation of microbiome findings to clinical practice is challenging. Here, we discuss current knowledge and applications in the field.

METHODS

We revisit some recent advances in the field of faecal microbiome analyses with a focus on covariate analyses and ecological interpretation.

RESULTS

Population-level characterization of gut microbiota variation among healthy volunteers has allowed identifying microbiome covariates required for clinical studies. Currently, microbiome research is moving from relative to quantitative approaches that will shed a new light on microbiota-host interactions in health and disease.

CONCLUSIONS

Covariate characterization and technical advances increase reproducibility of microbiome research. Targeted in vitro/in vivo intervention studies will accelerate clinical implementation of microbiota findings.

Emerging drugs for the treatment of clostridium difficile

INTRODUCTION

Clostridium difficile or Clostridioides difficile (C. difficile) infection represents the most common cause of healthcare-associated infection. Over the last decades, the incidence and severity of C. difficile infection is rapidly increasing, with a significant impact on morbidity and mortality, and burden on health care system. Orally administered vancomycin and fidaxomicin are the therapeutic options of choice for initial C. difficile infection and fecal microbiota transplant for the recurrence infection. Furthermore, in recent years several new antibiotics with narrow-spectrum activity and low intestinal resorption have been developed, including surotomycin, cadazolid, and ridinilazol, and novel toxoid vaccines are expected to be efficacious in the prevention of C. difficile infection. Areas covered: Literature review was performed to select publications about current guidelines and phase-II/III trials on emerging drugs. These include novel antibiotics, monoclonal antibodies, vaccines, and fecal microbiota transplantation. Expert opinion: We have today a wide spectrum of promising therapeutic possibilities against infection. Pivotal future clinical trials may be crucial in developing effective strategies to optimize outcomes, mainly in high-risk population.

The success of fecal microbial transplantation in Clostridium difficile infection correlates with bacteriophage relative abundance in the donor: a retrospective cohort study

Background: Fecal microbial transplantation (FMT) is used in the treatment of relapsing Clostridium difficile infection (rCDI). Failure rate for FMT is as high as 10% but the mechanisms contributing to a failed FMT are not understood. We utilized metagenomic data to identify the role of bacteria and bacteriophages on FMT success.Results: Subjects with rCDI (n = 19) received FMT from volunteer donors (n = 7) via colonoscopy. Twelve patients fully recovered after a single FMT, while seven patients required a subsequent FMT. DNA was extracted from patient and donor stool samples for shotgun metagenomic analysis. Metagenomics libraries were analyzed focusing on bacterial taxonomy and bacteriophage sequences. Gammaproteobacteria were dominant in rCDI patients prior to FMT largely due to elevated levels of Klebsiella and Escherichia. A successful FMT led to increased levels of Clostridia and Bacteroidia and a reduction in Gammaproteobacteria. In contrast, a failed FMT led to no significant changes in bacterial composition. Bacteriophages were classified during whole metagenomic analysis of each sample and were markedly different between rCDI patients, donors, and a healthy control cohort (n = 96). Bacteriophage sequence reads were increased in CDI patients compared with donors and healthy controls. Successful FMT donors had higher bacteriophage α-diversity and lower relative abundance compared to the donors of a failed initial FMT.Conclusions: In this retrospective analysis, FMTs with increased bacteriophage α-diversity were more likely to successfully treat rCDI. In addition, the relative number of bacteriophage reads was lower in donations leading to a successful FMT. These results suggest that bacteriophage abundance may have some role in determining the relative success of FMT.

Fecal Microbiota Transplant for Recurrent Clostridium difficile Infection in Pediatric Inflammatory Bowel Disease

OBJECTIVES

Recurrent Clostridium difficile infection (RCDI) increases morbidity and mortality in patients with inflammatory bowel disease (IBD). Fecal microbiota transplant (FMT) is known to be very effective for RCDI in non-IBD patients with cure rates up to 91%. The same success rates of FMT have not been reported in patients with IBD with RCDI, and the data in pediatrics are limited. We aimed to determine the effectiveness of FMT for RCDI in established pediatric patients with IBD.

METHODS

We performed a retrospective chart review of pediatric patients with IBD and RCDI (≥3 episodes) who underwent FMT via colonoscopy at a tertiary care IBD center. The primary outcome was the rate of RCDI within 60 days post-FMT. The secondary outcomes were recurrence rate by 6 months, rate of colectomy, and time to recurrence.

RESULTS

Of the 8 eligible patients, 6 had ulcerative colitis, 1 had IBD-unspecified, and 1 had Crohn disease. Median (interquartile range) age was 13 (11-14) years. All patients were on vancomycin at FMT. Two patients (25%) had RCDI by 60 days post-FMT and another 3 patients had RCDI between 60 days and 6 months. The median time to recurrence was 101 (40-139) days. Two patients (25%) who developed recurrence went to colectomy after FMT.

CONCLUSIONS

With a cure rate of 75% at 60 days, FMT administered for the treatment of RCDI may be an effective treatment option in pediatric IBD. However, there appears to be a significant rate of late recurrence of C difficile infection after 60 days in these patients.

Inhibition of Clostridium difficile in Mice Using a Mixture of Potential Probiotic Strains Enterococcus faecalis NM815, E. faecalis NM915, and E. faecium NM1015: Novel Candidates to Control C. difficile Infection (CDI)

This study is aimed at the isolation, identification, and characterization of potential probiotic strains capable of inhibiting Clostridium difficile in vitro and in vivo. Twenty isolates were isolated from infant fecal samples and screened against C. difficile using their cell-free supernatant. Only three isolates showed maximum inhibition from 56.05 to 60.60%, thus they were characterized for probiotic properties and safety. The results obtained approved their tolerance to the gastrointestinal tract conditions and safety profile. They were identified by sequencing 16S rRNA as Enterococcus faecalis NM815, E. faecalis NM915, and Enterococcus faecium NM1015. For in vivo evaluation, a viable mixture of these three strains (10⁹ CFU/mL) was administrated to a group of mice (treated group) in daily dose for 14 days, then followed by challenge with viable C. difficile (10⁵ CFU/mL) in daily dose for 7 days, then a second administration of a viable mixture of the three strains was done daily for 7 days. In addition, the control group was administered PBS buffer only and the untreated group received PBS buffer instead of the probiotic mixture before and after the challenge with C. difficile. The results obtained from histological analysis confirmed the effectiveness of our three potential probiotic strains which expressed inhibition of C. difficile and maintained the structural integrity of the liver and intestinal cells.

Do antimicrobial stewardship programme interventions reduce the rate of and protect against Clostridium difficile infection?

OBJECTIVES

Antimicrobial stewardship programmes (ASPs) have often been recommended as a viable solution to minimise the incidence of Clostridium difficile infection (CDI), which can be life-threatening. This study aimed to evaluate whether ASP interventions have contributed to reducing CDI rates.

METHODS

A retrospective review of ASP interventions issued from January 2013 to April 2014 was performed using data from the ASP database of Singapore General Hospital, a 1600-bed tertiary-care hospital in Singapore. A total of 283 interventions satisfied the inclusion criteria, of which commonly audited antibiotics were piperacillin/tazobactam (41.3%) and carbapenems (54.8%). Comparisons were made at 30days post-intervention between those with accepted or rejected interventions. The primary outcome was CDI incidence; secondary outcomes included length of hospitalisation post-intervention, 30-day mortality and CDI recurrence rate.

RESULTS

Whilst the median duration of antibiotic therapy was reduced by 2days (6days vs. 4 days; P<0.001), acceptance of ASP interventions did not alter primary CDI incidence at 30days (P=0.644) post-intervention. However, reduced CDI recurrence rates were observed for patients positive for CDI in the accepted patient group compared with the rejected group (0% vs. 37.5%; P=0.03), with no difference in CDI 30-day mortality between the two groups.

CONCLUSION

Intervention acceptance did not contribute to a significant reduction in CDI incidence but may be associated with lower recurrence rates, although further studies are required.

Clostridium difficile infections in teaching hospital in northern Finland

Background

The aim of this study to compare the incidence of Clostridium difficile (CD) infections in the five university hospital districts in Finland based on national register. The clinical findings of CD cases in the Oulu University Hospital (OUH) in one-year cohort were also analyzed.

Methods

The numbers of the CD cases from the national register were used for the hospital district comparison. A retrospective cohort study was conducted among all adult (> 16 years) patients treated in the OUH in 2013, who had positive CD toxin B gene test in stools. The selection of the cohort was based on the data from the OUH microbiology laboratory and the clinical characteristics were collected from hospital records.

Results

The incidence of CD findings in 2013 was higher in the OUH district than in the other four university hospital districts: 159 vs. 70 to 84 per 100,000 inhabitants.

In 2013, 261 patients had CD infection treated in the OUH. The yearly number of CD cases treated in the OUH in 2009–2016 varied between 221 and 287, and the corresponding proportion of positive CD findings out of all samples taken varied from 10.0 to 17.8%. A recurrent infection was seen in 58 patients (22%) while the all-cause 30 day mortality was 7.3%.

Conclusions

Diagnostic strategies differed nationally, which may explain the differences in CD incidence between the university hospital districts. In the OUH, no increase in the number of CD infections was seen in 2009–2016. Main characteristics of the patient cohort in the OUH were in harmony with earlier literature.

Oral faecal microbiota transplantation for the treatment of Clostridium difficile-associated diarrhoea in a dog: a case report

Background

Successful clinical outcomes of faecal microbiota transplantation (FMT) for recurrent Clostridium difficile infection have been reported in humans and a marmoset. However, it has been unclear whether oral FMT was effective for the treatment of C. difficile-associated diarrhoea in dogs.

Case presentation

An 8-month-old, intact male French bulldog was presented with a 4-month history of intermittent large bowel diarrhoea. Physical and clinical examinations did not identify any specific causes for diarrhoea. Real-time PCR analysis and immunochromatography detected C. difficile antigen and toxin A&B genes and proteins in a faecal sample. Based on these findings, diarrhoea in the dog was considered to be induced by C. difficile-associated colitis. The dog was treated with oral FMT, in which a faecal solution obtained from a healthy beagle was orally administered to the subject. Stool consistency and frequency and faecal blood and mucus became normal 2–3 days after oral FMT, and real-time PCR analysis and immunochromatography was negative for C. difficile antigen and toxin A&B genes and proteins. No adverse events were observed.

Conclusion

The present case report demonstrated that oral FMT was an effective treatment for C. difficile-associated diarrhoea in a dog. The findings in this report provide a rationale to evaluate clinical efficacy of oral FMT for other gastrointestinal diseases in dogs.