Introduction to the Special Issue on Clostridioides difficile

The Gram-positive, anaerobic bacterium Clostridioides difficile (CD) represents the most common cause of nosocomial diarrhea worldwide and is responsible for increased morbidity and mortality, and prolonged hospital stays [...]

Probiotics in Pediatrics. A Review and Practical Guide

The potential benefit of the administration of probiotics in children has been studied in many settings globally. Probiotics products contain viable micro-organisms that confer a health benefit on the host. Beneficial effects of selected probiotic strains for the management or prevention of selected pediatric conditions have been demonstrated. The purpose of this paper is to provide an overview of current available evidence on the efficacy of specific probiotics in selected conditions to guide pediatricians in decision-making on the therapeutic or prophylactic use of probiotic strains in children. Evidence to support the use of certain probiotics in selected pediatric conditions is often available. In addition, the administration of probiotics is associated with a low risk of adverse events and is generally well tolerated. The best documented efficacy of certain probiotics is for treatment of infectious gastroenteritis, and prevention of antibiotic-associated, Clostridioides difficile-associated and nosocomial diarrhea. Unfortunately, due to study heterogeneity and in some cases high risk of bias in published studies, a broad consensus is lacking for specific probiotic strains, doses and treatment regimens for some pediatric indications. The current available evidence thus limits the systematic administration of probiotics. The most recent meta-analyses and reviews highlight the need for more well-designed, properly powered, strain-specific and dedicated-dose response studies.

Protection from Lethal Clostridioides difficile Infection via Intraspecies Competition for Cogerminant

ABSTRACT Clostridioides difficile, a Gram-positive, spore-forming bacterium, is the primary cause of infectious nosocomial diarrhea. Antibiotics are a major risk factor for C. difficile infection (CDI), as they disrupt the gut microbial community, enabling increased germination of spores and growth of vegetative C. difficile. To date, the only single-species bacterial preparation that has demonstrated efficacy in reducing recurrent CDI in humans is nontoxigenic C. difficile. Using multiple infection models, we determined that precolonization with a less virulent strain is sufficient to protect from challenge with a lethal strain of C. difficile, surprisingly even in the absence of adaptive immunity. Additionally, we showed that protection is dependent on high levels of colonization by the less virulent strain and that it is mediated by exclusion of the invading strain. Our results suggest that reduction of amino acids, specifically glycine following colonization by the first strain of C. difficile, is sufficient to decrease germination of the second strain, thereby limiting colonization by the lethal strain. IMPORTANCE Antibiotic-associated colitis is often caused by infection with the bacterium Clostridioides difficile. In this study, we found that reduction of the amino acid glycine by precolonization with a less virulent strain of C. difficile is sufficient to decrease germination of a second strain. This finding demonstrates that the axis of competition for nutrients can include multiple life stages. This work is important, as it is the first to identify a possible mechanism through which precolonization with C. difficile, a current clinical therapy, provides protection from reinfection. Furthermore, our work suggests that targeting nutrients utilized by all life stages could be an improved strategy for bacterial therapeutics that aim to restore colonization resistance in the gut.

Protection from lethal Clostridioides difficile infection via intraspecies competition for co-germinant

Clostridioides difficile, a Gram-positive, spore-forming bacterium, is the primary cause of infectious nosocomial diarrhea. Antibiotics are a major risk factor for C. difficile infection (CDI) as they disrupt the gut microbial community, enabling increased germination of spores and growth of vegetative C. difficile. To date the only single-species bacterial preparation that has demonstrated efficacy in reducing recurrent CDI in humans is non-toxigenic C. difficile. Using multiple infection models we determined that pre-colonization with a less virulent strain is sufficient to protect from challenge with a lethal strain of C. difficile, surprisingly even in the absence of adaptive immunity. Additionally, we showed that protection is dependent on high levels of colonization by the less virulent strain and that it is mediated by exclusion of the invading strain. Our results suggest that reduction of amino acids, specifically glycine following colonization by the first strain of C. difficile is sufficient to decrease germination of the second strain thereby limiting colonization by the lethal strain.

Simultaneous detection and ribotyping of Clostridioides difficile, and toxin gene detection directly on fecal samples

Background: Clostridioides difficile is the most common cause of nosocomial diarrhea. Ribotyping of cultured strains by a PCR-based test is used to study potential transmission between patients. We aimed to develop a rapid test that can be applied directly on fecal samples for simultaneous detection and ribotyping of C. difficile, as well as detection of toxin genes.Methods: We developed a highly specific and sensitive primer set for simultaneous detection and ribotyping of C. difficile directly on total fecal DNA. Toxin genes were detected with primers adapted from Persson et al. (CMI, 2008). Our study set comprised 130 fecal samples: 65 samples with positive qPCR for C. difficile toxin A/B genes and 65 C. difficile qPCR negative samples. PCR products were analyzed by capillary gel electrophoresis. Results: Ribosomal DNA fragment peak profiles and toxin genes were detected in all 65 C. difficile positive fecal samples and in none of the 65 C. difficile negative samples. The 65 samples were assigned to 27 ribotypes by the Dutch reference laboratory. Our peak profiles corresponded to these ribotypes, except for two samples. During a C. difficile outbreak, patients were correctly allocated to the outbreak-cluster based on the results of direct fecal ribotyping, before C. difficile isolates were cultured and conventionally typed.Conclusion: C. difficile ribotyping directly on fecal DNA is feasible, with sensitivity and specificity comparable to that of diagnostic toxin gene qPCR and with ribotype assignment similar to that obtained by conventional typing on DNA from cultured isolates. This supports simultaneous diagnosis and typing to recognize an outbreak.

Initial vancomycin versus metronidazole for the treatment of first-episode non-severe Clostridioides difficile infection

Objective: Clostridioides difficile infection (CDI) is the leading cause of infectious nosocomial diarrhea. Although initial fidaxomicin or vancomycin treatment is recommended by most major guidelines to treat severe CDI, there exists varied recommendations for first-episode non-severe CDI. Given the discrepancy in current treatment guidelines, we sought to evaluate the use of initial vancomycin versus metronidazole for first-episode non-severe CDI. Methods: We conducted a retrospective cohort study of all adult inpatients with first-episode CDI at our institution from January 2013 to May 2018. The initial vancomycin versus initial metronidazole cohorts were examined using a multivariate logistic regression model. Results: The study cohort of 737 patients had a median age of 72.3 years, and 357 of these patients (48.4%) had hospital-acquired infection. Among 326 patients with non-severe CDI, recurrence, new incident infection, and 30-day mortality rates were 16.2%, 10.9%, and 5.3%, respectively, when treated with initial metronidazole, compared to 20.0%, 1.4%, and 10.0%, respectively, when treated with initial vancomycin. In an adjusted multivariable analysis, the use of initial vancomycin for the treatment of non-severe CDI was associated with a reduction in new incident infection (adjusted odds ratio [ORadj], 0.11; 95% confidence interval [CI], 0.02–0.86; P = .035), compared to initial metronidazole. Conclusions: Initial vancomycin was associated with a reduced rate of new incident infection in the treatment of adult inpatients with first-episode non-severe CDI. These findings support the use of initial vancomycin for all inpatients with CDI, when fidaxomicin is unavailable.

Antibiotic Susceptibility Profile of Clostridium Difficile Bacteria Isolated from Older Residents of a Nursing Home in Iran

Objectives: Clostridium difficile (C. diff) is a gram-positive anaerobic bacterium knwon as the most common cause of nosocomial diarrhea in nursing homes. The antibiotic susceptibility profile is the basic way for successful treatment due to antimicrobial resistance. This present study aims to assess the antibiotic susceptibility profile of C. diff isolated from older residents of a nursing home in Tehran, Iran. Methods & Materials: Forty-two isolates of C. diff were used in this study collected from 289 residents of Kahrizak Nursing Home. Antibiotic susceptibility testing was conducted by using disk-diffusion method, agar dilution method, and Epsilometer test (E-test). Results: All C. diff strains were susceptible to Metronidazole, Vancomycin, Rifampicin, Linezolid and Tigecycline. By using the disk-diffusion method, the highest rate of resistance was related to Clindamycin (100%), Levofloxacin (96.2%), Imipenem (81%), Azithromycin (61%) and Erythromycin (54.8%). All C. diff strains were susceptible to Metronidazole under E-test. Furthermore, 100% and 59.5% of strains were susceptible to Vancomycin and Erythromycin, respectively under agar dilution test. Conclusion: C. diff strains are sensitive to Vancomycin and Metronidazole. These two antibiotics can be used to treat C. diff infections in older adults. The disk diffusion method can be used as a screening test to determine antibiotic resistance.

The knowledge of nurses about prevention of infections caused by the bacteria Clostridium difficile

Introduction. Clostridium difficile is the leading cause of nosocomial diarrhea, associated with the use of antibiotics. The most common ways of transmitting the infection in hospitals are contaminated surfaces of the premises and the hands of medical staff. Methods. The study involved 68 nurses/technicians employed at the University Hospital Foca in the departments of surgery and internal medicine. As a research instrument, we used a specially designed questionnaire, created by the authors for the purpose of this research. Results. The research showed that 61.8% of respondents knew that hand washing with warm water and soap was considered the most effective prevention of the spread of infections, and 55.88% meant that they used chlorine-based preparations and hydrogen peroxide as the only effective disinfectant. Nurses with a work experience of less than 5 years showed better knowledge than other groups. Conclusion. The knowledge of nurses about the prevention of C. difficile infection is not at a satisfactory level, which indicates the growing need for education of nurses.

Initial vancomycin for first episode non-severe Clostridium difficile infection

BackgroundClostridium difficile infection (CDI) is an important cause of nosocomial diarrhea. Given the discrepancy in current treatment guidelines for mild CDI, we sought to evaluate the use of first-line vancomycin for the treatment of non-severe infection.MethodsWe conducted a retrospective cohort study of all adult inpatients with first episode CDI at our institution from January 2013 to May 2018. CDI was defined as a positive C. difficile loop-mediated isothermal amplification assay, in conjunction with ≥3 type 5–7 stools on the Bristol stool scale. To evaluate the impact of first-line vancomycin treatment on adverse clinical outcomes in patients with first episode non-severe CDI, the initial vancomycin vs. initial metronidazole cohorts were first examined in an unadjusted logistic regression analysis for any combination of relapse, recurrence, and all-cause 30-day mortality, followed by an adjusted multivariable analysis.ResultsA total of 737 cases were included. Patients had a median age of 72.3 years (Q1: 61.2, Q3: 83.3) and 628 (85.2%) were classified as non-severe CDI. Among patients with non-severe CDI (n = 628), relapse, recurrence, and mortality rates were 17.4%, 7.0%, and 11.4%, respectively, when treated with initial metronidazole, compared to 18.6%, 3.1%, and 7.8%, respectively, when treated with initial vancomycin. In an adjusted multivariable analysis, the use of first-line vancomycin for the treatment of non-severe CDI was associated with a reduction in recurrence or 30-day mortality (ORadj: 0.51; 95%CI: 0.28–0.94; P=0.03).ConclusionsInitial vancomycin was associated with reduced recurrence or all-cause 30-day mortality in the treatment of adult inpatients with first episode non-severe CDI. Our findings support the use of initial vancomycin for all C. difficile inpatients, irrespective of disease severity, as recommended by Infectious Diseases Society of America guidelines.

The Clostridioides difficile Cysteine-Rich Exosporium Morphogenetic Protein, CdeC, Exhibits Self-Assembly Properties That Lead to Organized Inclusion Bodies in Escherichia coli

ABSTRACT Clostridioides difficile is an obligately anaerobic, spore-forming, Gram-positive pathogenic bacterium that is considered the leading cause of nosocomial diarrhea worldwide. Recent studies have attempted to understand the biology of the outermost layer of C. difficile spores, the exosporium, which is believed to contribute to early interactions with the host. The fundamental role of the cysteine-rich proteins CdeC and CdeM has been described. However, the molecular details behind the mechanism of exosporium assembly are missing. The underlying mechanisms that govern exosporium assembly in C. difficile remain poorly studied, in part due to difficulties in obtaining pure soluble recombinant proteins of the C. difficile exosporium. In this work, we observed that CdeC was able to form organized inclusion bodies (IBs) in Escherichia coli filled with lamella-like structures separated by an interspace of 5 to 15 nm; however, CdeC expression in an E. coli strain with a more oxidative environment led to the loss of the lamella-like organization of CdeC IBs. Additionally, dithiothreitol (DTT) treatment of CdeC inclusion bodies released monomeric soluble forms of CdeC. Deletions in different portions of CdeC did not affect CdeC’s ability to aggregate and form oligomers stable under denaturation conditions but affected CdeC’s self-assembly properties. Overall, these observations have important implications in further studies elucidating the role of CdeC in the exosporium assembly of C. difficile spores. IMPORTANCE The endospore of Clostridioides difficile is the vehicle for transmission and persistence of the pathogen, and, specifically, the exosporium is the first contact between the host and the spore. The underlying mechanisms that govern exosporium assembly in C. difficile remain understudied, in part due to difficulties in obtaining pure soluble recombinant proteins of the C. difficile exosporium. Understanding the exosporium assembly’s molecular bases may be essential to developing new therapies against C. difficile infection.