The burden of CDI in the United States: a multifactorial challenge

How to develop a Controlled Human Infection Model for Clostridioides difficile

BACKGROUND

Clostridioides difficile (C. difficile) remains the leading cause of healthcare-associated diarrhoea, posing treatment challenges due to antibiotic resistance and high relapse rates. Fecal microbiota transplantation (FMT) is a novel treatment strategy to prevent relapses of C. difficile infection (CDI), however the exact components conferring colonisation resistance are unknown, hampering its translation to a medicinal product. Development of novel products independent of antibiotics, which increase colonisation resistance or induce protective immune mechanisms are urgently needed.

OBJECTIVES

To establish a framework for a Controlled Human Infection Model (CHIM) for C. difficile, in which healthy volunteers are exposed to toxigenic C. difficile spores, offering the possibility to test novel approaches and identify microbiota and immunological targets. Whereas experimental exposure to non-toxigenic C. difficile (NTCD) has been done before, a toxigenic C. difficile CHIM faces ethical, scientific, logistical and biosafety challenges.

SOURCES

Specific challenges in developing a C. difficile CHIM were discussed by a group of international experts during a workshop organized by Inno4Vac, an IHI-funded consortium.

CONTENT

The experts agreed that the main challenges are: developing a clinically relevant CHIM which induces mild to moderate CDI symptoms but no severe CDI, determining optimal C. difficile inoculum dose and understanding the timing and duration of antibiotic pre-treatment in inducing susceptibility to CDI in healthy volunteers.

IMPLICATIONS

Should these challenges be tackled, a C. difficile CHIM not only provides a way forward for the testing of novel products but also offers a framework for better understanding of the pathophysiology, pathogenesis and immunology of C. difficile colonisation and infection.

Best Practices in the Management of Clostridioides difficile Infection in Developing Nations

Clostridioides difficile infection (CDI) is a well-known cause of hospital-acquired infectious diarrhea in developed countries, though it has not been a top priority in the healthcare policies of developing countries. In the last decade, several studies have reported a wide range of CDI rates between 1.3% and 96% in developing nations, raising the concern that this could represent a healthcare threat for these nations. This review defines developing countries as those with a human development index (HDI) below 0.8. We aim to report the available literature on CDI epidemiology, diagnostics, management, and prevention in developing countries. We identify limitations for CDI diagnosis and management, such as limited access to CDI tests and unavailable oral vancomycin formulation, and identify opportunities to enhance CDI care, such as increased molecular test capabilities and creative solutions for CDI. We also discuss infection prevention strategies, including antimicrobial stewardship programs and opportunities emerging from the COVID-19 pandemic, which could impact CDI care.

Vaccines and monoclonal antibodies to prevent healthcare-associated bacterial infections

SUMMARYHealthcare-associated infections (HAIs) represent a burden for public health with a high prevalence and high death rates associated with them. Pathogens with a high potential for antimicrobial resistance, such as ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) and Clostridioides difficile, are responsible for most HAIs. Despite the implementation of infection prevention and control intervention, globally, HAIs prevalence is stable and they are mainly due to endogenous pathogens. It is undeniable that complementary to infection prevention and control measures, prophylactic approaches by active or passive immunization are needed. Specific groups at-risk (elderly people, chronic condition as immunocompromised) and also healthcare workers are key targets. Medical procedures and specific interventions are known to be at risk of HAIs, in addition to hospital environmental exposure. Vaccines or monoclonal antibodies can be seen as attractive preventive approaches for HAIs. In this review, we present an overview of the vaccines and monoclonal antibodies in clinical development for prevention of the major bacterial HAIs pathogens. Based on the current state of knowledge, we look at the challenges and future perspectives to improve prevention by these means.

Protective Effects of Huo Xiang Zheng Qi Liquid on Clostridioides difficile Infection on C57BL/6 Mice

BACKGROUND

Clostridioides difficile-associated disease (CDAD) is a major healthcare-associated infection. New treatment options for CDAD are needed. A traditional Chinese medicinal formula, Huo Xiang Zheng Qi (HXZQ), was chosen to test against CDAD in a mouse model.

METHODS

C57BL/6 mice were challenged with C difficile (ATCC 43255) orally; then received saline; vancomycin 25 mg/kg; or HXZQ in two different concentrations twice daily for 5 days. The animals' body weight; clinical signs; and survival rates were registered daily. Fecal pellets from each animal were taken for PCR analysis as a control of infection.

RESULTS

50% of the mice receiving saline died; 85.7% of the mice receiving vancomycin survived; 75% of the mice receiving HXZQ survived; and 87.5% of the mice receiving a 1:1 saline dilution of HXZQ survived. The HXZQ-treated groups were C. difficile PCR positive with loads less than that of the untreated mice. The weight loss in the vancomycin plus HXZQ 1:1 treated group; the vancomycin-treated group; and the untreated group were 3.08%, 4.06%, and 9.62%, respectively.

CONCLUSIONS

our results showed that HXZQ can protect mice from CDAD-related death as effectively as vancomycin and the combination of vancomycin and HXZQ may give even better protection.

More than a new name: Updates in the management of Clostridioides difficile infection

ABSTRACT

Infections from Clostridioides difficile (often called C. diff) have long presented challenges for both patients and clinicians. Traditionally, C. diff has been considered a nosocomial infection, but in recent years, a noticeable spike in community-acquired cases has occurred. C. diff infection (CDI) testing is often complicated, as various testing options with differing sensitivity and specificity for active infection are available. Also, recent guideline changes have altered the recommended treatment of infection. This article discusses recent changes to both the diagnosis and management of CDI and how they can be applied to everyday NP practice.

Pantothenate kinase: A promising therapeutic target against pathogenic Clostridium species

Current treatment of clostridial infections includes broad-spectrum antibiotics and antitoxins, yet antitoxins are ineffective against all Clostridiumspecies. Moreover, rising antimicrobial resistance (AMR) threatens treatment effectiveness and public health. This study therefore aimed to discover a common drug target for four pathogenic clostridial species, Clostridium botulinum, C. difficile, C. tetani, and C. perfringens through an in-silico core genomic approach. Using four reference genomes of C. botulinum, C. difficile, C. tetani, and C. perfringens, we identified 1484 core genomic proteins (371/genome) and screened them for potential drug targets. Through a subtractive approach, four core proteins were finally identified as drug targets, represented by type III pantothenate kinase (CoaX) and, selected for further analyses. Interestingly, the CoaX is involved in the phosphorylation of pantothenate (vitamin B5), which is a critical precursor for coenzyme A (CoA) biosynthesis. Investigation of druggability analysis on the identified drug target reinforces CoaX as a promising novel drug target for the selected Clostridium species. During the molecular screening of 1201 compounds, a known agonist drug compound (Vibegron) showed strong inhibitory activity against targeted clostridial CoaX. Additionally, we identified tazobactam, a beta-lactamase inhibitor, as effective against the newly proposed target, CoaX. Therefore, identifying CoaX as a single drug target effective against all four clostridial pathogens presents a valuable opportunity to develop a cost-effective treatment for multispecies clostridial infections.

Integrated Safety and Efficacy Analyses of Phase 3 Trials of a Microbiome Therapeutic for Recurrent CDI

INTRODUCTION

Recurrent Clostridioides difficile infection (rCDI) often occurs after standard-of-care antibiotics. VOWST oral spores (VOS, previously SER-109), an FDA-approved orally administered microbiome therapeutic, is indicated to prevent rCDI following antibiotics for rCDI.

OBJECTIVE, DESIGN, AND PATIENTS

To evaluate safety and efficacy of VOS from two phase 3 trials, (randomized, placebo-controlled [ECOSPOR III: NCT03183128] and open-label, single arm [ECOSPOR IV: NCT03183141]) of 349 adults with rCDI and prevalent comorbidities.

METHODS

VOS or placebo [ECOSPOR III only] (4 capsules once daily for 3 days). Integrated analysis of treatment-emergent adverse events (TEAEs) collected through week 8; serious TEAEs and TEAEs of special interest collected through week 24; and rates of rCDI (toxin-positive diarrhea requiring treatment) evaluated through weeks 8 and 24.

RESULTS

TEAEs were mostly mild or moderate and gastrointestinal. Most common treatment-related TEAEs were flatulence, abdominal pain and distension, fatigue, and diarrhea. There were 11 deaths (3.2%) and 48 patients (13.8%) with serious TEAEs, none treatment-related. The rCDI rate through week 8 was 9.5% (95% CI 6.6-13.0) and remained low through 24 weeks (15.2%; 95% CI 11.6-19.4). Safety and rCDI rates were consistent across subgroups including age, renal impairment/failure, diabetes, and immunocompromise/immunosuppression.

CONCLUSIONS

VOS was well tolerated and rates of rCDI remained low through week 24 including in those with comorbidities. These data support the potential benefit of VOS following antibiotics to prevent recurrence in high-risk patients.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT03183128 and NCT03183141.

Formal Single Atom Editing of the Glycosylated Natural Product Fidaxomicin Improves Acid Stability and Retains Antibiotic Activity

Fidaxomicin (Fdx) constitutes a glycosylated natural product with excellent antibacterial activity against various Gram-positive bacteria but is approved only for Clostridioides difficile infections. Poor water solubility and acid lability preclude its use for other infections. Herein, we describe our strategy to overcome the acid lability by introducing acid-stable S-linked glycosides. We describe the direct, diastereoselective modification of unprotected Fdx without the need to avoid air or moisture. Using our newly established approach, Fdx was converted to the single atom exchanged analogue S-Fdx, in which the acid labile O-glycosidic bond to the noviose sugar was replaced by the acid stable S-glycosidic bond. Studies of the antibacterial activity of a structurally diverse set of thioglycoside derivatives revealed high potency of acyl derivatives of S-Fdx against Clostridioides difficile (MIC range: 0.12-4 μg/mL) and excellent potency against Clostridium perfringens (MIC range: 0.06-0.5 μg/mL).

Mortality in clostridioides difficile infection among patients hospitalized at the university clinical hospital in Wroclaw, Poland - a 3-year observational study

BACKGROUND

In the last two decades, a significant increase in the number of Clostridioides difficile infection (CDI) cases has been observed. It is understandable to attempt to determine the factors that can predict the severity of the course of the infection and identify patients at risk of death. This study aimed to analyze the factors affecting the incidence and mortality of CDI in inpatient treatment at the University Clinical Hospital in Wrocław in 2016-2018.

METHODS

Statistical analysis of data obtained from patients' medical records was performed. Only patients with symptoms of infection and infection confirmed by laboratory tests were enrolled in the study. When analyzing the number of deaths, only adult patients who died in hospital wards were included. The quantitative data including laboratory tests, used antibiotics and Nutritional Risk Screening (NRS) were assessed. Also, the qualitative data such as sex, year of hospitalization, occurrence of diarrhoea on admission to the hospital, presence of additional diseases, as wee ad the use of antibacterial drugs or proton pump blockers and ranitidine during hospitalization were analyzed.

RESULTS

A total of 319 adult CDI patients (178 women and 141 men) were enrolled of which 80 people died (50 women and 30 men). The mean age of the patients was 72.08 ± 16.74 years. Over the entire period studied, the morbidity was 174 cases per 100,000 hospitalizations while mortality was 25.08%. The group of deceased patients was characterized by: older age (by 9.24 years), longer duration of hospitalization (by 10 days), reduced albumin levels (Rho = -0.235, p < 0.001), higher urea levels, use of more antibiotics, higher risk of malnutrition in NRS (Rho = 0.219, p < 0.001), higher incidence of sepsis, heart failure, stroke, hypothyroidism. Pneumonia was diagnosed twice as often. It was also shown that deceased patients were significantly more likely to take penicillin and fluoroquinolones.

CONCLUSIONS

In this study, the morbidity was lower, but mortality was higher compared to similar hospitals in Poland. CDI patients were characterized by older age, multimorbidity, extended hospitalization, and the use of broad-spectrum antibiotics. Risk factors for death included advanced age, prolonged hospital stays, lower albumin, higher urea, malnutrition, and comorbidities like heart failure, stroke, pneumonia, sepsis, and hypothyroidism. Increased antibiotic use, particularly penicillin and fluoroquinolones, was associated with a higher mortality risk.

Phenylthiazoles with potent & optimum selectivity toward Clostridium difficile

Clostridium difficile (C. difficile) is one of the most threatening bacteria globally, causing high mortality and morbidity in humans and animals, and is considered a public health threat that requires urgent and aggressive action. Interruption of the human gut microbiome and the development of antibiotic resistance urgently require development and synthesis of effective alternative antibiotics with minimal effects on the normal gut microbial flora. In this study, cyclization of the aminoguanidine head to the thiazole nucleus while maintaining its other pharmacophoric features leads to selective targeting of Clostridioides difficile as shown in the graphical abstract. The most promising compound, 5, was significantly more efficient than vancomycin and metronidazole against six strains of C. diff with MIC values as low as 0.030 μg mL-1. Additionally, compound 5 was superior to vancomycin and metronidazole, showing no inhibition toward nine tested strains of the normal human gut microbiota (>64 μg mL-1). The high safety profile of compound 5 was also observed with two cell lines HRT-18 and Vero cells.

Impact of oral vancomycin treatment duration on rate of Clostridioides difficile recurrence in patients requiring concurrent systemic antibiotics

BACKGROUND

There is a paucity of data guiding treatment duration of oral vancomycin for Clostridiodes difficile infection (CDI) in patients requiring concomitant systemic antibiotics.

OBJECTIVES

To evaluate prescribing practices of vancomycin for CDI in patients that required concurrent systemic antibiotics and to determine whether a prolonged duration of vancomycin (>14 days), compared to a standard duration (10-14 days), decreased CDI recurrence.

METHODS

In this retrospective cohort study, we evaluated adult hospitalized patients with an initial episode of CDI who were treated with vancomycin and who received overlapping systemic antibiotics for >72 hours. Outcomes of interest included CDI recurrence and isolation of vancomycin-resistant Enterococcus (VRE).

RESULTS

Among the 218 patients included, 36% received a standard duration and 64% received a prolonged duration of treatment for a median of 13 days (11-14) and 20 days (16-26), respectively. Patients who received a prolonged duration had a longer median duration of systemic antibiotic overlap with vancomycin (11 vs 8 days; P < .001) and significantly more carbapenem use and infectious disease consultation. Recurrence at 8 weeks (12% standard duration vs 8% prolonged duration; P = .367), recurrence at 6 months (15% standard duration vs 10% prolonged duration; P = .240), and VRE isolation (3% standard duration vs 9% prolonged duration; P = .083) were not significantly different between groups. Discontinuation of vancomycin prior to completion of antibiotics was an independent predictor of 8-week recurrence on multivariable logistic regression (OR, 4.8; 95% CI, 1.3-18.1).

CONCLUSIONS

Oral vancomycin prescribing relative to the systemic antibiotic end date may affect CDI recurrence to a greater extent than total vancomycin duration alone. Further studies are needed to confirm these findings.

A Gram-negative-selective antibiotic that spares the gut microbiome

Infections caused by Gram-negative pathogens are increasingly prevalent and are typically treated with broad-spectrum antibiotics, resulting in disruption of the gut microbiome and susceptibility to secondary infections1-3. There is a critical need for antibiotics that are selective both for Gram-negative bacteria over Gram-positive bacteria, as well as for pathogenic bacteria over commensal bacteria. Here we report the design and discovery of lolamicin, a Gram-negative-specific antibiotic targeting the lipoprotein transport system. Lolamicin has activity against a panel of more than 130 multidrug-resistant clinical isolates, shows efficacy in multiple mouse models of acute pneumonia and septicaemia infection, and spares the gut microbiome in mice, preventing secondary infection with Clostridioides difficile. The selective killing of pathogenic Gram-negative bacteria by lolamicin is a consequence of low sequence homology for the target in pathogenic bacteria versus commensals; this doubly selective strategy can be a blueprint for the development of other microbiome-sparing antibiotics.

Estimating Clostridioides difficile infection-associated readmission rates: A systematic review and meta-analysis

BACKGROUND

The economic burden of Clostridioides difficile infection (CDI) is considerable and mostly associated with a high frequency of hospitalizations. Numerous publications have demonstrated that CDI is associated with a higher risk of hospital readmission, but not always a specific rate or attributable to disease recurrence.

METHODS

In this systematic review, we describe the incidence of 30-day CDI-associated readmission rates and the effect of active interventions. Three search engines were utilized for the literature search, and a total of 9 studies were included in this review. Hospital readmission proportions from interventional and observational studies were analyzed through meta-analysis with random effects.

RESULTS

Two thousand five hundred and twenty-one articles were identified. After screening full-text articles, 9 eligible articles published between 2002 and 2023 met the inclusion criteria. In total, 132,862 CDI patients were evaluated. Thirty-day CDI-associated readmissions were defined as either an ICD9/10 code indicating CDI admission with a prior admission within the past 30 days (n = 4) or a medical chart evaluation of signs and symptoms consistent with CDI (diarrhea) along with a positive diagnostic test (n = 5) with a prior hospitalization for CDI within the past 30 days. Meta-analysis of observational studies estimated 30-day CDI readmissions were 6% (95% CI, 5%-7%). Three studies evaluated the effect of active interventions to reduce CDI-associated 30-day readmission rates. Two of 3 interventions reduced the likelihood of CDI-associated 30-day readmissions.

CONCLUSIONS

This systematic review identified a 6% rate of 30-day CDI-associated hospital readmission. Antimicrobial stewardship efforts and the use of specific therapeutics were shown to reduce these rates.

Breaking the Cycle of Recurrent Clostridioides difficile Infections: A Narrative Review Exploring Current and Novel Therapeutic Strategies

Clostridioides difficile is a toxin-producing bacteria that is a main cause of antibiotic-associated diarrhea. Clostridioides difficile infections (CDI) are associated with disruptions within the gastrointestinal (GI) microbiota which can be further exacerbated by CDI-targeted antibiotic treatment thereby causing recurrent CDI (rCDI) and compounding the burden placed on patients and the healthcare system. Treatment of rCDI consists of antibiotics which can be paired with preventative therapeutics, such as bezlotoxumab or fecal microbiota transplants (FMTs), if sustained clinical response is not obtained. Newer preventative strategies have been recently approved to assist in restoring balance within the GI system with the goal of preventing recurrent infections.

Microscopy methods for Clostridioides difficile

Microscopic technologies including light and fluorescent, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and cryo-electron microscopy have been widely utilized to visualize Clostridioides difficile at the molecular, cellular, community, and structural biology level. This comprehensive review summarizes the microscopy tools (fluorescent and reporter system) in their use to study different aspects of C. difficile life cycle and virulence (sporulation, germination) or applications (detection of C. difficile or use of antimicrobials). With these developing techniques, microscopy tools will be able to find broader applications and address more challenging questions to study C. difficile and C. difficile infection.

Evaluation of a surveillance system for Clostridioides difficile infections for Swiss hospitals

AIMS

This study evaluated an approach to establishing a comprehensive nationwide surveillance system for Clostridioides difficile infection in Switzerland. We report the results of patient-related surveillance and calculate the incidence rate of C. difficile infection in Switzerland in 2022.

METHODS

Initiated in 2017 by the National Centre for Infection Prevention (Swissnoso), in collaboration with the Swiss Centre for Antibiotic Resistance (ANRESIS), laboratory surveillance enables the automatic import of C. difficile infection laboratory data and is fully operational. However, the very limited number of participating laboratories impedes the generation of representative results. To address this gap, Swissnoso introduced patient-related surveillance, with a questionnaire-based survey used across Swiss acute care hospitals.

RESULTS

This survey revealed an incidence of 3.8 (Poisson 95% CI: 3.2-4.5) C. difficile infection episodes per 10,000 patient-days, just above the mean rate reported by the European Centre for Disease Prevention and Control (ECDC). Additionally, we report substantial heterogeneity in laboratory tests, diagnostic criteria and infection control practices among Swiss hospitals.

CONCLUSION

This study underscores the importance of a joint effort towards standardized surveillance practices in providing comprehensive insights into C. difficile infection epidemiology and effective prevention strategies in Swiss healthcare settings. The patient-related approach remains the gold standard for C. difficile infection surveillance, although it demands substantial resources and provides results only annually. The proposed implementation of nationwide automated laboratory-based surveillance would be pragmatic and efficient, empowering authorities and hospitals to detect outbreaks promptly and to correlate infection rates with antibiotic consumption.

Impact of doxycycline on Clostridioides difficile infection in patients hospitalized with community-acquired pneumonia

BACKGROUND

Antibiotic use is a significant risk factor associated with Clostridioides difficile (C difficile) infection (CDI). Community-acquired pneumonia (CAP) is a common infection leading to hospital admission and the use of antibiotics that are highly associated with CDI. It has been proposed that doxycycline, a tetracycline antibiotic, may be protective against CDI.

METHODS

A retrospective analysis was conducted in hospitalized patients in Veterans Affairs Hospitals across the United States to determine if doxycycline was associated with a decreased risk of CDI. The primary outcome was the development of CDI within 30 days of initiation of doxycycline or azithromycin, as part of a standard pneumonia regimen.

RESULTS

Approximately 156,107 hospitalized patients who received care at a Veterans Affairs Hospital and were diagnosed with CAP during the study timeframe were included. A 17% decreased risk of CDI was identified with doxycycline compared to azithromycin when used with ceftriaxone for the treatment of pneumonia (P = .03). In patients who had a prior history of CDI, doxycycline decreased the incidence of CDI by 45% (odds ratio 0.55; P = .02).

CONCLUSIONS

Doxycycline is associated with a lower risk of CDI compared to azithromycin when used for atypical coverage in CAP. Thus, patients who are at such risk may benefit from doxycycline as a first-line agent for atypical coverage, rather than the use of a macrolide antibiotic, if Legionella is not of concern.

Fight or flee, a vital choice for Clostridioides difficile

Clostridioides difficile is a leading cause of healthcare-associated infections, causing billions of economic losses every year. Its symptoms range from mild diarrhea to life-threatening damage to the colon. Transmission and recurrence of C. difficile infection (CDI) are mediated by the metabolically dormant spores, while the virulence of C. difficile is mainly due to the two large clostridial toxins, TcdA and TcdB. Producing toxins or forming spores are two different strategies for C. difficile to cope with harsh environmental conditions. It is of great significance to understand the molecular mechanisms for C. difficile to skew to either of the cellular processes. Here, we summarize the current understanding of the regulation and connections between toxin production and sporulation in C. difficile and further discuss the potential solutions for yet-to-be-answered questions.

Host-defense piscidin peptides as antibiotic adjuvants against Clostridioides difficile

The spore-forming intestinal pathogen Clostridioides difficile causes multidrug resistant infection with a high rate of recurrence after treatment. Piscidins 1 (p1) and 3 (p3), cationic host defense peptides with micromolar cytotoxicity against C. difficile, sensitize C. difficile to clinically relevant antibiotics tested at sublethal concentrations. Both peptides bind to Cu2+ using an amino terminal copper and nickel binding motif. Here, we investigate the two peptides in the apo and holo states as antibiotic adjuvants against an epidemic strain of C. difficile. We find that the presence of the peptides leads to lower doses of metronidazole, vancomycin, and fidaxomicin to kill C. difficile. The activity of metronidazole, which targets DNA, is enhanced by a factor of 32 when combined with p3, previously shown to bind and condense DNA. Conversely, the activity of vancomycin, which acts at bacterial cell walls, is enhanced 64-fold when combined with membrane-active p1-Cu2+. As shown through microscopy monitoring the permeabilization of membranes of C. difficile cells and vesicle mimics of their membranes, the adjuvant effect of p1 and p3 in the apo and holo states is consistent with a mechanism of action where the peptides enable greater antibiotic penetration through the cell membrane to increase their bioavailability. The variations in effects obtained with the different forms of the peptides reveal that while all piscidins generally sensitize C. difficile to antibiotics, co-treatments can be optimized in accordance with the underlying mechanism of action of the peptides and antibiotics. Overall, this study highlights the potential of antimicrobial peptides as antibiotic adjuvants to increase the lethality of currently approved antibiotic dosages, reducing the risk of incomplete treatments and ensuing drug resistance.

Pro-Inflammatory Cytokines Enhanced In Vitro Cytotoxic Activity of Clostridioides difficile Toxin B in Enteric Glial Cells: The Achilles Heel of Clostridioides difficile Infection?

Bacterial infections are characterized by an inflammatory response, which is essential for infection containment but is also responsible for negative effects on the host. The pathogen itself may have evolved molecular mechanisms to antagonize the antimicrobial effects of an inflammatory response and to enhance its pathogenicity using inflammatory response mediators, such as cytokines. Clostridioides difficile (C. difficile) infection (CDI) causes gastrointestinal diseases with markedly increasing global incidence and mortality rates. The main C. difficile virulence factors, toxin A and B (TcdA/TcdB), cause cytopathic/cytotoxic effects and inflammation. We previously demonstrated that TcdB induces enteric glial cell (EGC) apoptosis, which is enhanced by the pro-inflammatory cytokine tumor necrosis factor alpha plus interferon gamma (CKs). However, it is unknown whether CKs-enhanced TcdB cytotoxicity (apoptosis/necrosis) is affected by the timing of the appearance of the CKs. Thus, we simulated in vitro, in our experimental model with TcdB and EGCs, three main situations of possible interactions between TcdB and the timing of CK stimulation: before TcdB infection, concomitantly with infection, or at different times after infection and persisting over time. In these experimental conditions, which all represent situations of possible interactions between C. difficile and the timing of CK stimulation, we evaluated apoptosis, necrosis, and cell cycle phases. The CKs, in all of these conditions, enhanced TcdB cytotoxicity, which from apoptosis became necrosis when CK stimulation persisted over time, and was most relevant after 48 h of TcdB:EGCs interaction. Particularly, the enhancement of apoptosis by CKs was dependent on the TcdB dose and in a less relevant manner on the CK stimulation time, while the enhancement of necrosis occurred always independently of the TcdB dose and CK stimulation time. However, since in all conditions stimulation with CKs strongly enhanced the TcdB cytotoxicity, it always had a negative impact on C. difficile pathogenicity. This study might have important implications for the treatment of CDI.

Efficacy and Health-Related Quality of Life Impact of Fecal Microbiota, Live-jslm: A Post Hoc Analysis of PUNCH CD3 Patients at First Recurrence of Clostridioides difficile Infection

INTRODUCTION

Clostridioides difficile infection (CDI) causes symptoms of varying severity and negatively impacts patients' health-related quality of life (HRQL). Despite antibiotic treatment, recurrence of CDI (rCDI) is common and imposes clinical and economic burdens on patients. Fecal microbiota, live-jslm (REBYOTA [RBL]) is newly approved in the USA for prevention of rCDI following antibiotic treatments. We analyzed efficacy and HRQL impact of RBL vs. placebo in patients at first rCDI using data from the phase 3 randomized, double-blind placebo-controlled clinical trial, PUNCH CD3.

METHODS

This post hoc analysis included patients at first rCDI fromPUNCH CD3. Treatment success (i.e., absence of diarrhea within 8 weeks post-treatment) was analyzed adjusting for baseline patient characteristics. HRQL was measured using the Clostridioides difficile Quality of Life Survey (Cdiff32); absolute scores and change from baseline in total and domain (physical, mental, and social) scores were summarized and compared between arms. Analyses were conducted for the trial's blinded phase only.

RESULTS

Among 86 eligible patients (32.8% of the overall trial population, RBL 53 [61.6%], placebo 33 [38.4%]), RBL-treated patients had significantly lower odds of recurrence (i.e., greater probability of treatment success) at week 8 vs. placebo (odds ratio 0.35 [95% confidence interval 0.13, 0.98]). Probability of treatment success at week 8 was 81% for RBL and 60% for placebo, representing 21% absolute and 35% relative increases for RBL (crude proportions 79.2% vs. 60.6%; relative risk 0.53, p = 0.06). Additionally, RBL was associated with significantly higher Cdiff32 total (change score difference 13.5 [standard deviation 5.7], p < 0.05) and mental domain (16.2 [6.0], p < 0.01) scores vs. placebo from baseline to week 8.

CONCLUSION

Compared to placebo, RBL demonstrated a significantly higher treatment success in preventing further rCDI and enhanced HRQL among patients at first recurrence, establishing RBL as an effective treatment to prevent further recurrences in these patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT03244644.

Robust and Transparent Silver Oxide Coating Fabricated at Room Temperature Kills Clostridioides difficile Spores, MRSA, and Pseudomonas aeruginosa

Antimicrobial coatings can inhibit the transmission of infectious diseases when they provide a quick kill that is achieved long after the coating application. Here, we describe the fabrication and testing of a glass coating containing Ag2O microparticles that was prepared from sodium silicate at room temperature. The half-lives of both methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa on this coating are only 2-4 min. The half-life of Clostridioides difficile spores is about 9-12 min, which is extremely short for a spore. Additional tests on MRSA demonstrate that the coating retains its antimicrobial activity after abrasion and that an increased loading of Ag2O leads to a shorter half-life. This coating combines the properties of optical transparency, robustness, fast kill, and room temperature preparation that are highly desirable for an antimicrobial coating.

One size does not fit all - Trehalose metabolism by Clostridioides difficile is variable across the five phylogenetic lineages

Clostridioides difficile, the leading cause of antibiotic-associated diarrhoea worldwide, is a genetically diverse species which can metabolise a number of nutrient sources upon colonising a dysbiotic gut environment. Trehalose, a disaccharide sugar consisting of two glucose molecules bonded by an α 1,1-glycosidic bond, has been hypothesised to be involved in the emergence of C. difficile hypervirulence due to its increased utilisation by the RT027 and RT078 strains. Here, growth in trehalose as the sole carbon source was shown to be non-uniform across representative C. difficile strains, even though the genes for its metabolism were induced. Growth in trehalose reduced the expression of genes associated with toxin production and sporulation in the C. difficile R20291 (RT027) and M120 (RT078) strains in vitro, suggesting an inhibitory effect on virulence factors. Interestingly, the R20291 TreR transcriptional regulatory protein appeared to possess an activator function as its DNA-binding ability was increased in the presence of its effector, trehalose-6-phosphate. Using RNA-sequencing analysis, we report the identification of a putative trehalose metabolism pathway which is induced during growth in trehalose: this has not been previously described within the C. difficile species. These data demonstrate the metabolic diversity exhibited by C. difficile which warrants further investigation to elucidate the molecular basis of trehalose metabolism within this important gut pathogen.

Genomic Analysis of Clostridioides difficile Recovered from Horses in Western Australia

Clostridioides difficile poses an ongoing threat as a cause of gastrointestinal disease in humans and animals. Traditionally considered a human healthcare-related disease, increases in community-associated C. difficile infection (CDI) and growing evidence of inter-species transmission suggest a wider perspective is required for CDI control. In horses, C. difficile is a major cause of diarrhoea and life-threatening colitis. This study aimed to better understand the epidemiology of CDI in Australian horses and provide insights into the relationships between horse, human and environmental strains. A total of 752 faecal samples from 387 Western Australian horses were collected. C. difficile was isolated from 104 (30.9%) horses without gastrointestinal signs and 19 (37.8%) with gastrointestinal signs. Of these, 68 (55.3%) harboured one or more toxigenic strains, including C. difficile PCR ribotypes (RTs) 012 (n = 14), 014/020 (n = 10) and 087 (n = 7), all prominent in human infection. Whole-genome analysis of 45 strains identified a phylogenetic cluster of 10 closely related C. difficile RT 012 strains of equine, human and environmental origin (0-62 SNP differences; average 23), indicating recent shared ancestry. Evidence of possible clonal inter-species transmission or common-source exposure was identified for a subgroup of three horse and one human isolates, highlighting the need for a One Health approach to C. difficile surveillance.

Clostridioides difficile in Pigs and Dairy Cattle in Northern Italy: Prevalence, Characterization and Comparison between Animal and Human Strains

It has been observed that novel strains of Clostridioides difficile can rapidly emerge and move between animal and human hosts. The aim of this study was to investigate the prevalence of C. difficile in pigs and dairy cattle in northern Italy and to characterize and compare C. difficile animal strains with those from patients from the same geographical area. The C. difficile strains were isolated from animals from farms and slaughterhouses (cross-sectional studies) and from neonatal animals with enteric disorders in routine diagnostic investigations (passive surveillance). Samples positive for C. difficile were found in 87% of the pig farms and in 40% of the cattle farms involved in the cross-sectional studies, with a 20% prevalence among suckling piglets and 6.7% prevalence in neonatal calves, with no significant difference between animals with and without diarrheal symptoms. The prevalence of C. difficile in older animal categories was significantly lower. This result suggests that young age is an important risk factor for C. difficile colonization. In cross-sectional studies at slaughterhouses, in both the heavy pigs and dairy cows examined, only 2% of the intestinal content samples were positive for C. difficile and no contamination was found on the surface of the carcasses. Considering passive surveillance, the prevalence rates of positive samples were 29% in piglets and 1.4% in calves. Overall, 267 strains of animal origin and 97 from humans were collected. In total, 39 ribotypes (RTs) were identified, with RT 078 and RT 018 being predominant among animals and humans, respectively. Several RTs overlapped between animals and patients. In particular, RT 569 was identified as an emergent type in our country. Resistance to erythromycin and moxifloxacin was widely diffused among C. difficile strains, regardless of origin. This study supports C. difficile as a pathogen of one-health importance and highlights the need for a collaborative approach between physicians and veterinarians to control and prevent infections that are able to cross species and geographical barriers.

Clostridioides difficile resistance to antibiotics, including post-COVID-19 data

INTRODUCTION

Updating data on Clostridioides difficile antibiotic resistance is important for treatment improvement of C. difficile infections (CDIs).

AREAS COVERED

Results from 20 countries were included. The mean resistance to 2 mg/l vancomycin, 2 mg/l metronidazole, 4 mg/l moxifloxacin, and 4 mg/l clindamycin was 4.7% (0 to ≥ 26% in two studies), 2.6% (0 to ≥ 40% in 3 studies), 34.9% (6.6->80%), and 61.0% (30->90%), respectively. Resistance to erythromycin (>60-88%), rifampin (>23-55.0%), imipenem (0.6 to > 78% in a clone), tigecycline (0-<5.0%), and fidaxomicin (0-2%) was also found. Resistance to ≥ 5 antibiotics of different classes was reported in some countries. High resistance and multidrug resistance were observed in hypervirulent and epidemic strains. Although only 1% of COVID-19 patients had CDIs, the proportion might be underestimated.

EXPERT OPINION

C. difficile antimicrobial susceptibility varied by country/region, study period, and circulating ribotypes. For CDI treatment, fidaxomicin (preferably) or vancomycin is recommended, while metronidazole is suitable for mild infections. New approaches, including biotherapeutics (Rebyota), strains, antibiotics (ridinilazole and ibezapolstat), and monoclonal antibodies/cocktails merit further evaluation. Because of the resistance rate variations, C. difficile antibiotic susceptibility should be regularly monitored. Post-COVID-19 resistance should be separately presented. Some discrepancies between vancomycin and metronidazole results need to be clarified.