Comparison of fidaxomicin, thuricin CD, vancomycin and nisin highlights the narrow spectrum nature of thuricin CD.

Vancomycin and metronidazole are commonly used treatments for Clostridioides difficile infection (CDI). However, these antibiotics have been associated with high levels of relapse in patients. Fidaxomicin is a new treatment for CDI that is described as a narrow spectrum antibiotic that is minimally active on the commensal bacteria of the gut microbiome. The aim of this study was to compare the effect of fidaxomicin on the human gut microbiome with a number of narrow (thuricin CD) and broad spectrum (vancomycin and nisin) antimicrobials. The spectrum of activity of each antimicrobial was tested against 47 bacterial strains by well-diffusion assay. Minimum inhibitory concentrations (MICs) were calculated against a select number of these strains. Further, a pooled fecal slurry of 6 donors was prepared and incubated for 24 h with 100 µM of each antimicrobial in a mini-fermentation system together with a no-treatment control. Fidaxomicin, vancomycin, and nisin were active against most gram positive bacteria tested in vitro, although fidaxomicin and vancomycin produced larger zones of inhibition compared to nisin. In contrast, the antimicrobial activity of thuricin CD was specific to C. difficile and some Bacillus spp. The MICs showed similar results. Thuricin CD exhibited low MICs (<3.1 µg/mL) for C. difficile and Bacillus firmus, whereas fidaxomicin, vancomycin, and nisin demonstrated lower MICs for all other strains tested when compared to thuricin CD. The narrow spectrum of thuricin CD was also observed in the gut model system. We conclude that the spectrum of activity of fidaxomicin is comparable to that of the broad-spectrum antibiotic vancomycin in vitro and the broad spectrum bacteriocin nisin in a complex community.

Incorporating patient, nursing and environmental factors into antimicrobial stewardship: effects of simplifying treatment from cefuroxime to ceftriaxone.

AIM: Our antimicrobial guidelines (AGs) were changed in 2021 to recommend once-daily ceftriaxone in place of three-times-daily cefuroxime as preferred cephalosporin. This analysis sought to assess the effects of this on incidence of Clostridioides difficile infection (CDI), third-generation cephalosporin-resistant Enterobacterales (3GCR-E) and resource utilisation. METHOD: Before and after analysis of 30-day CDI and 3GCR-E incidence following receipt of cefuroxime/ceftriaxone pre- and post-AG change. Total nursing time and waste production relating to cefuroxime/ceftriaxone delivery were calculated pre- and post-change. RESULTS: CDI incidence was 0.6% pre- and 1.0% post-change (adjusted odds ratio [aOR] 1.44, p=0.07) and 3GCR-E incidence 3.5% and 3.1% (aOR 0.90, p=0.33). Mean per-quarter estimated nursing administration time decreased from 2,065 to 1,163 hours (902 nurse-hour reduction) and antibiotic-related waste generation from 1,131kg to 748kg (383kg reduction). Overall days of therapy per-quarter of cefuroxime/ceftriaxone were unchanged between periods. CONCLUSION: This simplification of our AG from a three-times-daily to a once-daily antibiotic resulted in considerable savings for our hospital (roughly 1.7 full-time equivalent nurses and over a tonne of waste yearly), with no significant increases in CDI or 3GCR-E. The impact of dosing schedules on non-antibiotic-spectrum factors, such as nursing time and resource usage, is worthy of consideration when designing AGs.

Efficacy Assessment of the Co-Administration of Vancomycin and Metronidazole in Clostridioides difficile-Infected Mice Based on Changes in Intestinal Ecology.

Vancomycin (VAN) and metronidazole (MTR) remain the current drugs of choice for the treatment of non-severe Clostridioides difficile infection (CDI); however, while their co-administration has appeared in clinical treatment, the efficacy varies greatly and the mechanism is unknown. In this study, a CDI mouse model was constructed to evaluate the therapeutic effects of VAN and MTR alone or in combination. For a perspective on the intestinal ecology, 16S rRNA amplicon sequencing and non-targeted metabolomics techniques were used to investigate changes in the fecal microbiota and metabolome of mice under the co-administration treatment. As a result, the survival rate of mice under co-administration was not dramatically different compared to that of single antibiotics, and the former caused intestinal tissue hyperplasia and edema. Co-administration also significantly enhanced the activity of amino acid metabolic pathways represented by phenylalanine, arginine, proline, and histidine, decreased the level of deoxycholic acid (DCA), and downregulated the abundance of beneficial microbes, such as Bifidobacterium and Akkermansia. VAN plays a dominant role in microbiota regulation in co-administration. In addition, co-administration reduced or increased the relative abundance of antibiotic-sensitive bacteria, including beneficial and harmful microbes, without a difference. Taken together, there are some risks associated with the co-administration of VAN and MTR, and this combination mode should be used with caution in CDI treatment.

Clinical outcomes and treatment necessity in patients with toxin-negative Clostridioides difficile stool samples.

PURPOSE: The clinical significance of negative toxin enzyme immunoassays (EIA) for Clostridioides difficile infections (CDIs) is unclear. Our study aimed to investigate the significance of toxin EIA-negative in the diagnosis and prognosis of CDI. METHODS: All stool specimens submitted for C. difficile toxin EIA testing were cultured to isolate C. difficile. In-house PCR for tcdA, tcdB, cdtA, and cdtB genes were performed using C. difficile isolates. Stool specimens were tested with C. difficile toxins A and B using EIA kit (RIDASCREEN Clostridium difficile toxin A/B, R-Biopharm AG, Darmstadt, Germany). Characteristics and subsequent CDI episodes of toxin EIA-negative and -positive patients were compared. RESULTS: Among 190 C. difficile PCR-positive patients, 83 (43.7%) were toxin EIA-negative. Multivariate analysis revealed independent associations toxin EIA-negative results and shorter hospital stays (OR = 0.98, 95% CI 0.96-0.99, p = 0.013) and less high-risk antibiotic exposure in the preceding month (OR = 0.38, 95% CI 0.16-0.94, p = 0.035). Toxin EIA-negative patients displayed a significantly lower white blood cell count rate (11.0 vs. 35.4%, p < 0.001). Among the 54 patients who were toxin EIA-negative and did not receive CDI treatment, three (5.6%) were diagnosed with CDI after 7-21 days without complication. CONCLUSION: Our study demonstrates that toxin EIA-negative patients had milder laboratory findings and no complications, despite not receiving treatment. Prolonged hospitalisation and exposure to high-risk antibiotics could potentially serve as markers for the development of toxin EIA-positive CDI.

New treatment approaches for Clostridioides difficile infections: alternatives to antibiotics and fecal microbiota transplantation.

Clostridioides difficile causes a range of debilitating intestinal symptoms that may be fatal. It is particularly problematic as a hospital-acquired infection, causing significant costs to the health care system. Antibiotics, such as vancomycin and fidaxomicin, are still the drugs of choice for C. difficile infections, but their effectiveness is limited, and microbial interventions are emerging as a new treatment option. This paper focuses on alternative treatment approaches, which are currently in various stages of development and can be divided into four therapeutic strategies. Direct killing of C. difficile (i) includes beside established antibiotics, less studied bacteriophages, and their derivatives, such as endolysins and tailocins. Restoration of microbiota composition and function (ii) is achieved with fecal microbiota transplantation, which has recently been approved, with standardized defined microbial mixtures, and with probiotics, which have been administered with moderate success. Prevention of deleterious effects of antibiotics on microbiota is achieved with agents for the neutralization of antibiotics that act in the gut and are nearing regulatory approval. Neutralization of C. difficile toxins (iii) which are crucial virulence factors is achieved with antibodies/antibody fragments or alternative binding proteins. Of these, the monoclonal antibody bezlotoxumab is already in clinical use. Immunomodulation (iv) can help eliminate or prevent C. difficile infection by interfering with cytokine signaling. Small-molecule agents without bacteriolytic activity are usually selected by drug repurposing and can act via a variety of mechanisms. The multiple treatment options described in this article provide optimism for the future treatment of C. difficile infection.

[Fulminant Clostridioides difficile infection during treatment with FLT3 inhibitor for acute myeloid leukemia].

An 80-year-old man with FLT3-TKD mutation-positive acute myeloid leukemia (AML) relapsed during consolidation therapy with venetoclax/azacitidine and was started on gilteritinib as salvage therapy. On the day after treatment initiation, febrile neutropenia was observed, but the fever resolved promptly after initiation of antimicrobial therapy. On the fifth day after completion of antimicrobial therapy, the patient experienced fever and watery diarrhea over 10 times a day, and a diagnosis of Clostridioides difficile infection (CDI) was made based on stool examination. The patient was treated with intravenous metronidazole, but renal dysfunction, hypotension, and hypoxemia developed, and a CT scan showed pleural and intraperitoneal effusion, significant intestinal wall thickening, and intestinal dilatation. Fidaxomicin was started under general monitoring in the intensive care unit and response was achieved. The patient was discharged from the intensive care unit on the 18th day after the onset of CDI. We report this case not only due to the rarity of fulminant CDI during AML treatment, but also because it is a valuable example of effective treatment of fulminant CDI with fidaxomicin.

SER-109 (VOWST™): A Review in the Prevention of Recurrent Clostridioides difficile Infection.

SER-109 (VOWST™; fecal microbiota spores, live-brpk) is a live biotherapeutic product indicated to prevent the recurrence of Clostridioides difficile infection (CDI) in patients 18 years of age and older following standard of care (SOC) antibacterial treatment for recurrent CDI. It is a purified bacterial spore suspension sourced from healthy donors. As the first oral faecal microbiota product approved for prevention of recurrent CDI, SER-109 is administered as four capsules once daily for three consecutive days. In a well-designed, placebo-controlled, phase III trial (ECOSPOR III), SER-109 significantly reduced the risk of recurrent CDI at 8 weeks post-treatment, with a durable response seen at 6 months post-treatment. Treatment with SER-109 was also associated with rapid and steady improvement in health-related quality of life compared with placebo. SER-109 was generally well tolerated, with a safety profile similar to that of placebo. The most common adverse events were of mild to moderate severity and generally gastrointestinal in nature. Thus, with the convenience of oral administration and lack of necessity for cold storage, SER-109 is a valuable option for preventing further CDI recurrence in adults following antibacterial treatment for recurrent CDI.

Clostridioides difficile is a type of bacteria that can produce toxins leading to infection of the large intestine. Symptoms of C. difficile infection (CDI) range from mild diarrhoea to severe life-threatening sepsis. Treatment is usually antibiotics to kill the toxin-producing bacteria and resolve symptoms. However, antibiotics can disrupt the gut microbiota and leave individuals at risk of CDI recurrence. SER-109 (VOWST^™; fecal microbiota spores, live-brpk) is a microbiome therapy containing purified live bacterial spores extracted from donated human faecal matter intended to repair the microbiome. It is given as four oral capsules per day over three consecutive days to prevent the recurrence of CDI in adults following standard antibiotic treatment. In a phase III clinical trial, patients with recurrent CDI who received SER-109 had a significantly lower rate of CDI recurrence at 8 weeks than those who received placebo, and this response was sustained through 6 months. SER-109 was generally well tolerated, and most adverse events were mild or moderate in severity. With the convenience of oral administration and no refrigeration requirements, SER-109 is a valuable option for preventing further CDI recurrence in adults who have received antibiotics for recurrent CDI.

Epidemiological and clinical burden of Clostridioides difficile infections and recurrences between 2015 - 2019: the RECUR Germany study.

BACKGROUND: This real-world study assessed the epidemiology and clinical complications of Clostridioides difficile infections (CDIs) and recurrences (rCDIs) in hospital and community settings in Germany from 2015 - 2019. METHODS: An observational retrospective cohort study was conducted among adult patients diagnosed with CDI in hospital and community settings using statutory health insurance claims data from the BKK database. A cross-sectional approach was used to estimate the annual incidence rate of CDI and rCDI episodes per 100,000 insurants. Patients' demographic and clinical characteristics were described at the time of first CDI episode. Kaplan-Meier method was used to estimate the time to rCDIs and time to complications (colonic perforation, colectomy, loop ileostomy, toxic megacolon, ulcerative colitis, peritonitis, and sepsis). A Cox model was used to assess the risk of developing complications, with the number of rCDIs as a time-dependent covariate. RESULTS: A total of 15,402 CDI episodes were recorded among 11,884 patients. The overall incidence of CDI episodes declined by 38% from 2015 to 2019. Most patients (77%) were aged ≥ 65 years. Around 19% of CDI patients experienced at least one rCDI. The median time between index CDI episode to a rCDI was 20 days. The most frequent complication within 12-months of follow-up after the index CDI episode was sepsis (7.57%), followed by colectomy (3.20%). The rate of complications increased with the number of rCDIs. The risk of any complication increased by 31% with each subsequent rCDI (adjusted hazard ratio [HR]: 1.31, 95% confidence interval: 1.17;1.46). CONCLUSIONS: CDI remains a public health concern in Germany despite a decline in the incidence over recent years. A substantial proportion of CDI patients experience rCDIs, which increase the risk of severe clinical complications. The results highlight an increasing need of improved therapeutic management of CDI, particularly efforts to prevent rCDI.

The Role of Probiotics in the Prevention of Clostridioides difficile Infection in Patients with Chronic Kidney Disease.

In patients suffering from chronic kidney disease (CKD), substantial unfavourable alterations in the intestinal microbiota composition, i.e., dysbiosis, have been noted. The main causes of such dysbiosis among others are insufficient dietary fibre content in the diet, fluid restrictions, medications used, and physical activity limitation. One clinically important consequence of dysbiosis in CKD patients is high risk of Clostridioides difficile infection (CDI). In observational studies, it was found that CDI is more frequent in CKD patients than in the general population. This appears to be related to high hospitalization rate and more often antibiotic therapy use, leading up to the occurrence of dysbiosis. Therefore, the use of probiotics in CKD patients may avert changes in the intestinal microbiota, which is the major risk factor of CDI. The aim of this review paper is to summarize the actual knowledge concerning the use of probiotics in CDI prevention in CKD patients in the context of CDI prevention in the general population.

Effective treatment of Clostridioides difficile infection improves survival and affects graft-versus-host disease: a multicenter study by the Polish Adult Leukemia Group.

Clostridioides difficile infection (CDI) is the most common cause of infectious diarrhea after allogeneic hematopoietic cell transplantation (allo-HCT). The impact of CDI and its treatment on allo-HCT outcomes and graft-versus-host disease (GVHD), including gastrointestinal GVHD (GI-GVHD) is not well established. This multicenter study assessed real-life data on the first-line treatment of CDI and its impact on allo-HCT outcomes. Retrospective and prospective data of patients with CDI after allo-HCT were assessed. We noted statistically significant increase in the incidence of acute GVHD and acute GI-GVHD after CDI (P = 0.005 and P = 0.016, respectively). The first-line treatment for CDI included metronidazole in 34 patients, vancomycin in 64, and combination therapy in 10. Treatment failure was more common with metronidazole than vancomycin (38.2% vs. 6.2%; P < 0.001). The need to administer second-line treatment was associated with the occurrence or exacerbation of GVHD (P < 0.05) and GI-GVHD (P < 0.001) and reduced overall survival (P < 0.05). In the multivariate analysis, the risk of death was associated with acute GVHD presence before CDI (hazard ratio [HR], 3.19; P = 0.009) and the need to switch to second-line treatment (HR, 4.83; P < 0.001). The efficacy of the initial CDI treatment affects survival and occurrence of immune-mediated GI-GVHD after allo-HCT. Therefore, agents with higher efficacy than metronidazole (vancomycin or fidaxomicin) should be administered as the first-line treatment.

Review article: The epidemiology and management of Clostridioides difficile infection-A clinical update.

BACKGROUND: Clostridioides difficile is the most common cause of healthcare-associated infection, and severe cases can result in significant complications. While anti-microbial therapy is central to infection management, adjunctive therapies may be utilised as preventative strategies. AIM: This article aims to review updates in the epidemiology, diagnosis, and management, including treatment and prevention, of C. difficile infections. METHODS: A narrative review was performed to evaluate the current literature between 1986 and 2023. RESULTS: The incidence of C. difficile infection remains significantly high in both hospital and community settings, though with an overall decline in recent years and similar surveillance estimates globally. Vancomycin and fidaxomicin remain the first line antibiotics for treatment of non-severe C. difficile infection, though due to lower recurrence rates, infectious disease society guidelines now favour use of fidaxomicin. Faecal microbiota transplantation should still be considered to prevent recurrent C. difficile infection. However, in the past year the field has had a significant advancement with the approval of the first two live biotherapeutic products-faecal microbiota spores-live brpk, an oral capsule preparation, and faecal microbiota live-jslm-both indicated for the prevention of recurrent C. difficile infection, with additional therapies on the horizon. CONCLUSION: Although the prevalence of C. difficile infection remains high, there have been significant advances in the development of novel therapeutics and preventative measures following changes in recent practice guidelines, and will continue to evolve in the future.

Antibacterial activity of ibezapolstat against antimicrobial-resistant clinical strains of Clostridioides difficile.

Antimicrobial resistance is emerging in clinical strains of Clostridioides difficile. Ibezapolstat (IBZ) is a DNA polymerase IIIC inhibitor that has completed phase II clinical trials. IBZ has potent in vitro activity against wild-type, susceptible strains but its effect on C. difficile strains with reduced susceptibility to metronidazole (MTZ), vancomycin (VAN), or fidaxomicin (FDX) has not been tested. The primary objective of this study was to test the antibacterial properties of IBZ against multidrug-resistant C. difficile strains. The in vitro activity, bactericidal, and time-kill activity of IBZ versus comparators were evaluated against 100 clinical strains of which 59 had reduced susceptibility to other C. difficile antibiotics. Morphologic changes against a multidrug resistance strain were visualized by light and scanning electron microscopy. The overall IBZ MIC50/90 values (µg/mL) for evaluated C. difficile strains were 4/8, compared with 2/4 for VAN, 0.5/1 for FDX, and 0.25/4 for MTZ. IBZ MIC50/90 values did not differ based on non-susceptibility to antibiotic class or number of classes to which strains were non-susceptible. IBZ bactericidal activity was similar to the minimum inhibitory concentration (MIC) and maintained in wild-type and non-susceptible strains. Time-kill assays against two laboratory wild-type and two clinical non-susceptible strains demonstrated sustained IBZ activity despite reduced killing by comparator antibiotics for IBZ and VAN non-susceptible strains. Microscopy visualized increased cell lengthening and cellular damage in multidrug-resistant strains exposed to IBZ sub-MIC concentrations. This study demonstrated the potent antibacterial activity of IBZ against a large collection of C. difficile strains including multidrug-resistant strains. This study highlights the therapeutic potential of IBZ against multidrug-resistant strains of C. difficile.

AGA Clinical Practice Guideline on Fecal Microbiota-Based Therapies for Select Gastrointestinal Diseases.

BACKGROUND & AIMS: Fecal microbiota-based therapies include conventional fecal microbiota transplant and US Food and Drug Administration-approved therapies, fecal microbiota live-jslm and fecal microbiota spores live-brpk. The American Gastroenterological Association (AGA) developed this guideline to provide recommendations on the use of fecal microbiota-based therapies in adults with recurrent Clostridioides difficile infection; severe to fulminant C difficile infection; inflammatory bowel diseases, including pouchitis; and irritable bowel syndrome. METHODS: The guideline was developed using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) framework to prioritize clinical questions, identify patient-centered outcomes, and conduct an evidence synthesis. The guideline panel used the Evidence-to-Decision framework to develop recommendations for the use of fecal microbiota-based therapies in the specified gastrointestinal conditions and provided implementation considerations for clinical practice. RESULTS: The guideline panel made 7 recommendations. In immunocompetent adults with recurrent C difficile infection, the AGA suggests select use of fecal microbiota-based therapies on completion of standard of care antibiotics to prevent recurrence. In mildly or moderately immunocompromised adults with recurrent C difficile infection, the AGA suggests select use of conventional fecal microbiota transplant. In severely immunocompromised adults, the AGA suggests against the use of any fecal microbiota-based therapies to prevent recurrent C difficile. In adults hospitalized with severe or fulminant C difficile not responding to standard of care antibiotics, the AGA suggests select use of conventional fecal microbiota transplant. The AGA suggests against the use of conventional fecal microbiota transplant as treatment for inflammatory bowel diseases or irritable bowel syndrome, except in the context of clinical trials. CONCLUSIONS: Fecal microbiota-based therapies are effective therapy to prevent recurrent C difficile in select patients. Conventional fecal microbiota transplant is an adjuvant treatment for select adults hospitalized with severe or fulminant C difficile infection not responding to standard of care antibiotics. Fecal microbiota transplant cannot yet be recommended in other gastrointestinal conditions.

Primary clostridium difficile infection in patients with ulcerative colitis: Case report and literature review.

RATIONALE: Inflammatory bowel disease (IBD), including Crohn disease (CD) and ulcerative colitis (UC), is a chronic immune-mediated disorder characterized by inflammation of the gastrointestinal tract. Patients with IBD are susceptible to various complications, including the coexistence of Clostridioides difficile infection (CDI). The incidence of IBD combined with difficile infection is higher in patients with compromised immune function, which can lead to increased mortality. PATIENT CONCERNS: A 43-year-old male presented with recurrent episodes of mucus and bloody stools persisting for more than a month without any identifiable triggering factors. Initially, the stool consistency was normal, but it progressively shifted to a loose and watery texture, with up to 8 occurrences daily. DIAGNOSES: This case underscores the diagnosis of severe UC through colonoscopy and colonic biopsy, along with the supplementary identification of a positive result for Clostridioides difficile in the fecal sample. INTERVENTIONS: The patient initiated infliximab therapy alongside a full vancomycin course, demonstrating the potential effectiveness of this intervention in managing early-stage ulcerative colitis with concurrent Clostridioides difficile infection. OUTCOMES: Following the completion of a full vancomycin course, the patient initiated infliximab therapy. The patient was free from significant discomfort, exhibited no fever, and had no mucopurulent bloody stools. A follow-up blood test indicated reduced inflammatory markers compared to the preoperative period, and the stools were normal. LESSONS: We illustrate the potential effectiveness of this medication by presenting an in-depth case report of a patient with early-stage UC. The report outlines the patient inclusion of infliximab to better manage UC inflammation alongside an adjunct vancomycin regimen, given the ineffectiveness of mesalazine therapy and the concurrent presence of Clostridium difficile infection. This case prompts consideration of therapeutic approaches for complex UC and contributes to advancing both research and clinical practice. Nonetheless, we should remain attentive to the variations and potential risks unique to each patient in order to formulate personalized treatment strategies.

Epidemiology of Clostridioides difficile infection at a tertiary care facility in Saudi Arabia: Results of prospective surveillance.

OBJECTIVES: To determine the incidence of Clostridioides difficile infection (CDI) and the frequency of known risk factors. METHODS: A prospective hospital-based surveillance for CDI, according to the Centers for Disease Control and Prevention criteria, was carried out from July 2019 to March 2022 for all inpatients aged more than one year in Prince Sultan Military Medical City, Riyadh, Saudi Arabia. RESULTS: A total of 139 cases of CDI were identified during the survey among 130 patients admitted in the hospital. Most cases were incident (n=130; 93.5%), and almost three-quarters (n=102; 73.4%) were hospital-onset (HO) CDI, with an incidence rate of 1.62 per 10,000 patient days (PD). The highest rates were noted in intensive care units with an incidence rate of 3 per 10,000 PD and wards for immunocompromised patients with an incidence rate of 2.72 per 10,000 PD. The most prevalent risk factor for CDI was acid-reducing drugs (72.6%). Vancomycin (48%) and ciprofloxacin (25%) were the most frequently prescribed antibiotics for patients with CDI. Clostridioides difficile infection complications were identified in 5.7% of the cases, with a reported 28-day mortality rate of 3.8%. CONCLUSION: In our hospital, HO-CDI incidence rate is lower than that in high-income countries. National multicenter surveillance is needed to evaluate the actual burden of CDI in Saudi Arabia.

Probiotics for Prevention and Treatment of Clostridium difficile Infection.

Probiotics have been claimed as a valuable tool to restore the balance in the intestinal microbiota following a dysbiosis caused by, among other factors, antibiotic therapy. This perturbed environment could favor the overgrowth of Clostridium difficile, and in fact, the occurrence of C. difficile-associated infections (CDI) is increasing in recent years. In spite of the high number of probiotics able to in vitro inhibit the growth and/or toxicity of this pathogen, its application for treatment or prevention of CDI is still scarce since there are not enough well-defined clinical studies supporting efficacy. Only a few strains, such as Lactobacillus rhamnosus GG and Saccharomyces boulardii, have been studied in more extent. The increasing knowledge about the probiotic mechanisms of action against C. difficile, some of them reviewed here, makes promising the application of these live biotherapeutic agents against CDI. Nevertheless, more effort must be paid to standardize the clinical studies conducted to evaluate probiotic products, in combination with antibiotics, in order to select the best candidate for C. difficile infections.

European Practice for CDI Treatment.

Clostridioides difficile infection (CDI) remains a significant cause of morbidity and mortality worldwide. Historically, two antibiotics (metronidazole and vancomycin) and a recent third (fidaxomicin) have been used for CDI treatment; convincing data are now available showing that metronidazole is the least efficacious agent. The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) management guidance for CDI were updated in 2021. This guidance document outlines the treatment options for a variety of CDI clinical scenarios and for non-antimicrobial management (e.g., faecal microbiota transplantation, FMT). One of the main changes is that metronidazole is no longer recommended as first-line CDI treatment. Rather, fidaxomicin is preferred on the basis of reduced recurrence rates with vancomycin as an acceptable alternative. Recommended options for recurrent CDI now include bezlotoxumab as well as FMT.A 2017 survey of 20 European countries highlighted variation internationally in CDI management strategies. A variety of restrictions were in place in 65% countries prior to use of new anti-CDI treatments, including committee/infection specialist approval or economic review/restrictions. This survey was repeated in November 2022 to assess the current landscape of CDI management practices in Europe. Of 64 respondents from 17 countries, national CDI guidelines existed in 14 countries, and 11 have already/plan to incorporate the ESCMID 2021 CDI guidance, though implementation has not been surveyed in 6. Vancomycin is the most commonly used first-line agent for the treatment of CDI (n = 42, 66%), followed by fidaxomicin (n = 30, 47%). Six (9%) respondents use metronidazole as first-line agent for CDI treatment, whereas 22 (34%) only in selected low-risk patient groups. Fidaxomicin is more likely to be used in high-risk patient groups. Availability of anti-CDI therapy influenced prescribing in six respondents (9%). Approval pre-prescription was required before vancomycin (n = 3, 5%), fidaxomicin (n = 10, 6%), bezlotoxumab (n = 11, 17%) and FMT (n = 10, 6%). Implementation of CDI guidelines is rarely audited.Novel anti-CDI agents are being evaluated; it is not yet clear what will be the roles of these agents. The treatment of recurrent CDI is particularly troublesome, and several different live biotherapeutics are being developed, in addition to FMT.

Clostridioides difficile Biofilm.

Clostridioides difficile infection (CDI), previously Clostridium difficile infection, is a symptomatic infection of the large intestine caused by the spore-forming anaerobic, gram-positive bacterium Clostridioides difficile. CDI is an important healthcare-associated disease worldwide, characterized by high levels of recurrence, morbidity, and mortality. CDI is observed at a higher rate in immunocompromised patients after antimicrobial therapy, with antibiotics disrupting the commensal microbiota and promoting C. difficile colonization of the gastrointestinal tract.A rise in clinical isolates resistant to multiple antibiotics and the reduced susceptibility to the most commonly used antibiotic molecules have made the treatment of CDI more complicated, allowing the persistence of C. difficile in the intestinal environment.Gut colonization and biofilm formation have been suggested to contribute to the pathogenesis and persistence of C. difficile. In fact, biofilm growth is considered as a serious threat because of the related antimicrobial tolerance that makes antibiotic therapy often ineffective. This is the reason why the involvement of C. difficile biofilm in the pathogenesis and recurrence of CDI is attracting more and more interest, and the mechanisms underlying biofilm formation of C. difficile as well as the role of biofilm in CDI are increasingly being studied by researchers in the field.Findings on C. difficile biofilm, possible implications in CDI pathogenesis and treatment, efficacy of currently available antibiotics in treating biofilm-forming C. difficile strains, and some antimicrobial alternatives under investigation will be discussed here.

In vivo evaluation of Clostridioides difficile enoyl-ACP reductase II (FabK) inhibition by phenylimidazole unveils a promising narrow-spectrum antimicrobial strategy.

Clostridioides difficile infection (CDI) is a leading cause of hospital-acquired diarrhea, which often stems from disruption of the gut microbiota by broad-spectrum antibiotics. The increasing prevalence of antibiotic-resistant C. difficile strains, combined with disappointing clinical trial results for recent antibiotic candidates, underscores the urgent need for novel CDI antibiotics. To this end, we investigated C. difficile enoyl ACP reductase (CdFabK), a crucial enzyme in de novo fatty acid synthesis, as a drug target for microbiome-sparing antibiotics. To test this concept, we evaluated the efficacy and in vivo spectrum of activity of the phenylimidazole analog 296, which is validated to inhibit intracellular CdFabK. Against major CDI-associated ribotypes 296 had an Minimum inhibitory concentration (MIC90) of 2 µg/mL, which was comparable to vancomycin (1 µg/mL), a standard of care antibiotic. In addition, 296 achieved high colonic concentrations and displayed dosed-dependent efficacy in mice with colitis CDI. Mice that were given 296 retained colonization resistance to C. difficile and had microbiomes that resembled the untreated mice. Conversely, both vancomycin and fidaxomicin induced significant changes to mice microbiomes, in a manner consistent with prior reports. CdFabK, therefore, represents a potential target for microbiome-sparing CDI antibiotics, with phenylimidazoles providing a good chemical starting point for designing such agents.

Clostridioides difficile infections, recurrences, and clinical outcomes in real-world settings from 2015 to 2019: The RECUR England study.

OBJECTIVE: To estimate the epidemiological and clinical burden of Clostridioides difficile infections (CDIs) and recurrences (rCDIs) in England. METHODS: This retrospective study included adult patients diagnosed with CDI (community or hospital settings) over 2015-2019 from Clinical Practice Research Datalink and Hospital Episode Statistics databases. Incidences of CDI and rCDI were determined annually. Time to subsequent rCDI was estimated by Kaplan-Meier method. Rates of complications were assessed within 12 months from index episode. Association of risk factors with complications was evaluated using a Cox regression model. RESULTS: A total of 52,443 CDI episodes were recorded among 36,913 patients. Of these, 75% were aged ≥65 years, 59% were women; 73% were treated in community settings. CDI incidence remained stable (111 episodes per 100,000 patients in 2019). Around 21% of patients had ≥1 rCDI. Sepsis (12%) was the most common complication, followed by colectomy and ulcerative colitis. Age, gender, comorbidities, rCDI, preindex medical procedures, hospitalizations and consultations, and CDI treatment in hospital, were found to increase the risk of complication. CONCLUSIONS: CDI remains a concern in England. The study highlights the importance of managing primary and rCDI episodes via effective and improved therapies to prevent fatal complications.