Clostridioides difficile: achados epidemiológicos em animais domésticos em um Hospital Veterinário Universitário em ­ Teresina, PI / Clostridioides difficile: epidemiological findings in domestic animals in a University Veterinary Hospital in Teresina, PI

O objetivo deste estudo foi analisar a prevalência de Clostridioides difficile e suas toxinas (A/B) nas fezes de animais domésticos de um Hospital Veterinário Universitário de Teresina - PI. A detecção de C. difficile e suas toxinas foi realizada por meio de um ensaio imunoenzimático, denominado C. Diff Quik Chek Complete® (TECHLAB), capaz de detectar antígeno Glutamato Desidrogenase (GDH) e as toxinas A/B produzidas pelo bacilo, realizado em amostras fecais de cães (C. lupus) e e gatos (Felis catus) coletadas entre agosto de 2019 a setembro de 2020. Um total de 54 amostras fecais foram analisadas, das quais 16 foram positivas para C. difficile (29,63%). 68,75% (11/16) pertenciam a caninos, enquanto 31,25% (5/16) a felinos. Amostras diarreicas e não diarreicas foram utilizadas para o estudo e uma maior prevalência do bacilo pôde ser identificada em amostras diarreicas (33%). Nenhuma das amostras apresentou toxinas do patógeno. Os achados deste estudo evidenciam que C.difficile está presente no estado do Piauí. Foi possível identificá-lo em todas as espécies e em amostras diarreicas ou não, demonstrando que essa infecção pode se manifestar de formasintomática e assintomática, levantando a possibilidade de infecção cruzada entre o animal e seu tutor.

The aim of this study was to analyze the prevalence of Clostridioides difficile and its toxins (A/B) in the feces of domestic animals at a University Veterinary Hospital in Teresina - PI. The detection of C. difficile and its toxins was performed by an immunogenic enzyme, called C. Diff Quik Chek Complete® (TECHLAB), capable of detecting antigen glutamate dehydrogenase (GDH) and A/B toxins produced by this bacillus, performed in fecal samples of dogs (C. lupus) and cats (Felis catus) collected between August 2019 and September 2020.:54 stools were analyzed, of which 16 were positive for C. difficile (29.63%). 68.75% (11/16) belonged to canines, while 3.25% (5/16) to felines. Diarrheal and non-diarrheal diseases are used for the study and a higher prevalence of bacillus can be identified in diarrheal diseases (33%). None of the samples present pathogen toxins. The results of this study show that C. difficile is present in the state of Piauí. It can be identified in all species and in diarrheal or non-diarrheic samples, demonstrating that this infection can be symptomatic and asymptomatic, giving the possibility of cross-infection between the animal and its owner.

Fecal Microbiota Transplantation Increases Colonic IL-25 and Dampens Tissue Inflammation in Patients with Recurrent Clostridioides difficile.

Clostridioides difficile infection (CDI) is the most common hospital-acquired infection in the United States. Antibiotic-induced dysbiosis is the primary cause of susceptibility, and fecal microbiota transplantation (FMT) has emerged as an effective therapy for recurrence. We previously demonstrated in the mouse model of CDI that antibiotic-induced dysbiosis reduced colonic expression of interleukin 25 (IL-25) and that FMT protected in part by restoring IL-25 signaling. Here, we conducted a prospective study in humans to test if FMT induced IL-25 expression in the colons of patients with recurrent CDI (rCDI). Colonic biopsy specimens and blood were collected at the time of FMT and 60 days later. Colon biopsy specimens were analyzed for IL-25 protein levels, total tissue transcriptome, and epithelium-associated microbiota before and after FMT, and peripheral immune cells were immunophenotyped. FMT increased alpha diversity of the colonic microbiota and levels of IL-25 in colonic tissue. In addition, FMT increased expression of homeostatic genes and repressed inflammatory genes. Finally, circulating Th17 cells were decreased post-FMT. The increase in levels of the cytokine IL-25 accompanied by decreased inflammation is consistent with FMT acting in part to protect from recurrent CDI via restoration of commensal activation of type 2 immunity. IMPORTANCE Fecal microbiota transplantation (FMT) is an effective treatment for C. difficile infection for most patients; however, introducing a complex mixture of microbes also has had unintended consequences for some patients. Attempts to create a standardized probiotic therapeutic that recapitulates the efficacy of FMT have been unsuccessful to date. We sought to understand what immune markers are changed in patients undergoing FMT to treat recurrent C. difficile infection and identified an immune signaling molecule, IL-25, that was restored by FMT. This finding indicates that adjunctive therapy with IL-25 could be useful in treating C. difficile infection.

Toxigenic Clostridium difficile-mediated diarrhoea in hematopoietic stem cell transplantation in-patients: rapid diagnosis and efficient treatment.

Allogenic hematopoietic stem cell transplant (HSCT) recipients are susceptible to any kind of infectious agents including Clostridium difficile. We studied 86 allogenic-HSCT patients who faced diarrhoea while receiving antibiotics. DNA from stool samples were explored for the presence of C. difficile toxin genes (tcdA; tcdB) by multiplex real-time PCR. Results showed nine toxigenic C. difficile amongst which seven were positive for both toxins and two were positive for tcdB. Six of toxigenic C. difficile organisms harbouring both toxin genes were also isolated by toxigenic culture. Clostridium difficile infection was controlled successfully with oral Metronidazole and Vancomycin in the confirmed infected patients.

Epidemiologic and Clinical Characteristics of Clostridioides difficile Infections in Hospitalized and Outpatient Pediatric Oncology and Hematopoietic Stem Cell Transplant Patients.

BACKGROUND: The epidemiology and clinical course of Clostridioides difficile infection (CDI) in children, especially with cancer, are poorly defined. We aim to describe the epidemiology, clinical features and outcomes of CDI and to identify risk factors for recurrence in a pediatric oncology center. METHODS: This is a retrospective cohort study of CDI in pediatric oncology and hematopoietic stem cell transplant (HSCT) patients in 2016 and 2017. CDI cases were identified by positive C. difficile test in symptomatic patients. CDI episodes were classified as incident, duplicate or recurrent and community-onset, hospital-onset or community-onset healthcare facility-associated. Data about clinical course and outcomes were abstracted. Risk factors for CDI recurrence were assessed by logistic regression. RESULTS: One hundred seventy-eight patients 1 year of age and older developed 291 CDI episodes; 78% were incident and 22% recurrent. Underlying diagnoses were leukemia/lymphoma (57%) and solid/brain tumors (41%); 30% were HSCT recipients. Antibiotics, chemotherapy, antacids, steroids and laxatives were received by 96%, 82%, 70%, 47% and 15%, respectively. Half of the patients were neutropenic. Twenty-two percent of outpatients with CDI required hospitalization. Chemotherapy was delayed in 25%. There were no intensive care unit admissions nor deaths due to CDI. Exposure to H2-antagonists was identified as an independent risk factor for CDI recurrence. CONCLUSIONS: Although CDI in pediatric oncology and HSCT patients was associated with chemotherapy delay and hospitalization in approximately a quarter of patients, it was not associated with morbidity or mortality because patients had no attributable intensive care unit admission nor death. H2-antagonists are independent risk factors for CDI recurrence.

Fecal Microbiota Transplantation Influences Procarcinogenic Escherichia coli in Recipient Recurrent Clostridioides difficile Patients.

BACKGROUND & AIMS: Patients with multiple recurrent Clostridioides difficile infection (rCDI) have a disturbed gut microbiota that can be restored by fecal microbiota transplantation (FMT). Despite extensive screening, healthy feces donors may carry bacteria in their intestinal tract that could have long-term health effects, such as potentially procarcinogenic polyketide synthase-positive (pks+) Escherichia coli. Here, we aim to determine whether the pks abundance and persistence of pks+E coli is influenced by pks status of the donor feces. METHODS: In a cohort of 49 patients with rCDI treated with FMT and matching donor samples-the largest cohort of its kind, to our knowledge-we retrospectively screened fecal metagenomes for pks+E coli and compared the presence of pks in patients before and after treatment and to their respective donors. RESULTS: The pks island was more prevalent (P = .026) and abundant (P < .001) in patients with rCDI (pre-FMT, 27 of 49 [55%]; median, 0.46 reads per kilobase per million [RPKM] pks) than in healthy donors (3 of 8 donors [37.5%], 11 of 38 samples [29%]; median, 0.01 RPKM pks). The pks status of patients post-FMT depended on the pks status of the donor suspension with which the patient was treated (P = .046). Particularly, persistence (8 of 9 cases) or clearance (13 of 18) of pks+E coli in pks+ patients was correlated to pks in the donor (P = .004). CONCLUSIONS: We conclude that FMT contributes to pks+E coli persistence or eradication in patients with rCDI but that donor-to-patient transmission of pks+E coli is unlikely.

Identification of linear epitopes on the flagellar proteins of Clostridioides difficile.

Clostridioides difficile (C. difficile) is an opportunistic anaerobic bacterium that causes severe diseases of the digestive tract of humans and animals. One of the possible methods of preventing C. difficile infection is to develop a vaccine. The most promising candidates for vaccine antigens are the proteins involved in the adhesion phenomena. Among them, the FliC and FliD are considered to be suitable candidates. In this paper, the FliC and FliD protein polypeptide epitopes were mapped in silico and by using PEPSCAN procedure. We identified four promising epitopes: 117QRMRTLS123, 205MSKAG209 of FliC and 226NKVAS230, 306TTKKPKD312 of FliD protein. We showed that 117QRMRTLS123 sequence is not only located in TLR5-binding and activating region, as previously shown, but forms an epitope recognized by C. difficile-infected patients' antibodies. 205MSKAG209 is a C. difficile-unique, immunogenic sequence that forms an exposed epitope on the polymerized flagella structure which makes it a suitable vaccine antigen. 226NKVAS230 and 306TTKKPKD312 are well exposed and possess potential protective properties according to VaxiJen analysis. Our results open the possibility to use these epitopes as suitable anti-C. difficile vaccine antigens.

Clostridioides difficile toxins enhanced the in vitro production of CXC chemokine ligand 2 and tumor necrosis factor-α via Toll-like receptors in macrophages.

Introduction. Clostridioides difficile infection (CDI) causes toxin-mediated enteropathy, such as antibiotic-associated diarrhoea and pseudomembranous colitis. Rho-glucosylating toxin A (TcdA) and toxin B (TcdB) have been clearly implicated in pathogenesis, whereas the virulence of binary toxin (CDT) is still debated.Hypothesis statement. We hypothesized that CDT is involved in the host immune response and plays a pivotal role in establishing virulence by modulating pro-inflammatory cytokine production; this is achieved through the integral Toll-like receptor (TLR) signalling pathways.Aim. The aim of the present study was to determine whether and how CDT impacts macrophages compared to TcdA or TcdB by examining the induction of CXC chemokine ligand 2 (CXCL2) and tumour necrosis factor-α (TNF-α), both of which are crucial in mediating local and systematic inflammatory responses.Methodology. RAW264.7 cells or transfected human embryonic kidney (HEK) 293 T cells were incubated with TcdA, TcdB, or CDT. In some experiments, a neutralizing antibody against TLR2 or TLR4, or myeloid differentiation 88 inhibitory peptide were added. The amount of CXCL2 and TNF-α secreted was then measured.Results. In RAW264.7 macrophages, CXCL2 and TNF-α were produced via the Toll-like receptor 2 (TLR2) or Toll-like receptor 4 (TLR4) pathway in a TcdA, TcdB, or CDT dose-dependent manner. Interleukin-8 secretion was induced in TLR4/MD2/CD14-transfected, but not in TLR2-transfected, HEK 293 T cells following TcdB or CDT exposure.Conclusion. Our results showed that C. difficile toxins, including CDT, enhanced macrophage-mediated CXCL2 and TNF-α production via TLR2 and TLR4, indicating that CDT affects host immune responses.

The Importance of Therapeutically Targeting the Binary Toxin from Clostridioides difficile.

Novel therapeutics are needed to treat pathologies associated with the Clostridioides difficile binary toxin (CDT), particularly when C. difficile infection (CDI) occurs in the elderly or in hospitalized patients having illnesses, in addition to CDI, such as cancer. While therapies are available to block toxicities associated with the large clostridial toxins (TcdA and TcdB) in this nosocomial disease, nothing is available yet to treat toxicities arising from strains of CDI having the binary toxin. Like other binary toxins, the active CDTa catalytic subunit of CDT is delivered into host cells together with an oligomeric assembly of CDTb subunits via host cell receptor-mediated endocytosis. Once CDT arrives in the host cell's cytoplasm, CDTa catalyzes the ADP-ribosylation of G-actin leading to degradation of the cytoskeleton and rapid cell death. Although a detailed molecular mechanism for CDT entry and host cell toxicity is not yet fully established, structural and functional resemblances to other binary toxins are described. Additionally, unique conformational assemblies of individual CDT components are highlighted herein to refine our mechanistic understanding of this deadly toxin as is needed to develop effective new therapeutic strategies for treating some of the most hypervirulent and lethal strains of CDT-containing strains of CDI.

World Society of Emergency Surgery-American Association for the Surgery of Trauma Guidelines for management of Clostridioides (Clostridium) difficile infection in surgical patients: An executive summary.

ABSTRACT: In the last three decades, the dramatic worldwide increase in incidence and severity of Clostridioides difficile infection (CDI) (formerly Clostridium difficile infection) has made CDI a global public health challenge. Surgery is a known risk factor for development of CDI yet surgery is also a treatment option in severe cases of CDI. The World Society of Emergency Surgery guidelines for management of CDI in surgical patients were published in 2015. In 2019, the guidelines were revised and updated according to the grading of recommendations assessment, development and evaluation methodology. This executive summary is intended to consolidate knowledge on the management of CDI focusing on aspects that a general and emergency surgeon should know about the prevention and the management of CDI, by providing a practical and concise version of the original guidelines.

Impact of synbiotics on gut microbiota during early life: a randomized, double-blind study.

Human milk is considered the optimal nutrition for infants and found to contain significant numbers of viable bacteria. The aim of the study was to assess the effects of a specific synbiotic combination at doses closer to the bacterial cells present in human milk, on intestinal bifidobacteria proportions (relative abundance), reduction of potential pathogens and gut physiological conditions. A clinical study was conducted in 290 healthy infants aged from 6 to 19 weeks. Infants received either a control infant formula or one of the two investigational infant formulas (control formula with 0.8 g/100 ml scGOS/lcFOS and Bifidobacterium breve M-16V at either 1 × 104 cfu/ml or 1 × 106 cfu/ml). Exclusively breastfed infants were included as a reference. Analyses were performed on intention-to-treat groups and all-subjects-treated groups. After 6 weeks of intervention, the synbiotics at two different doses significantly increased the bifidobacteria proportions in healthy infants. The synbiotic supplementation also decreased the prevalence (infants with detectable levels) and the abundance of C. difficile. Closer to the levels in the breastfed reference group, fecal pH was significantly lower while L-lactate concentrations and acetate proportions were significantly higher in the synbiotic groups. All formulas were well tolerated and all groups showed a comparable safety profile based on the number and severity of adverse events and growth. In healthy infants, supplementation of infant-type bifidobacterial strain B. breve M-16V, at a dose close to bacterial numbers found in human milk, with scGOS/lcFOS (9:1) created a gut environment closer to the breastfed reference group. This specific synbiotic mixture may also support gut microbiota resilience during early life.Clinical Trial Registration This clinical study named Color Synbiotics Study, was registered in ClinicalTrials.gov on 18 March 2013. Registration number is NCT01813175. https://clinicaltrials.gov/ct2/show/NCT01813175 .

A contemporary review of Clostridioides difficile infections in patients with haematologic diseases.

Clostridioides (Clostridium) difficile (C. difficile) infection is one of the most common causes of increased morbidity and mortality. Approximately 500 000 C. difficile infections (CDIs) occur each year in the United States, and they result in more than 29 000 deaths. Patients with haematologic diseases are at a higher risk for this infection due to frequent hospitalization and exposure to treatment-associated risk factors. Whilst several currently available antimicrobial agents offer resolution, recurrence of infection remains a major concern. Recent advancement in deciphering C. difficile virulence mechanisms and identification of its allies in contributing to the infection has led to the development of alternative treatment strategies. Here, we will provide a contemporary discussion of how major risk factors in haematologic diseases, such as immunosuppression, chemoradiation, use of antibiotic, proton pump inhibitor and opioid, and deficiency in butyrate and antimicrobial peptides contribute to C. difficile infection. Next, we will highlight different approaches to control and mitigate this infection such as antibiotic stewardship and faecal microbiota transplantation. Finally, we will explore several emerging treatments such as use of pre- and probiotics, immunotherapy and microbiome-sparing agents.

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

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.

Diarrea clostridial. Un patógeno nosocomial a tener en cuenta / Clostridial diarrhea. A nosocomial pathogen to take into account

La diarrea clostridial es una enfermedad aguda con compromiso colónico que puede poner en riesgo la vida de un paciente. Su agente etiológico es el Clostridium difficile y se ha asociado al uso indiscriminado y por largo plazo de antibióticos de amplio espectro. Su cuadro clínico es variable, puede ir desde un cuadro de diarrea hasta la perforación colónica, que puede determinar la realización de una colectomía de urgencia o incluso provocar la muerte del enfermo. El diagnóstico de certeza se realiza mediante la detección de la toxina clostridial en materia fecal, por técnicas de inmunoensayo enzimático. La terapéutica se realiza con metronidazol o vancomicina por vía oral. El tratamiento quirúrgico está indicado ante la presencia de megacolon tóxico o perforación intestinal, y en aquellos pacientes con toxicidad sistémica con fracaso de la terapéutica médica. (AU)

Clostridial diarrhea is an acute disease with colonic involvement that can be life-threatening for a patient. Its etiologic agent is the Clostridium difficile and it has been associated with the indiscriminate and long-term use of broad-spectrum antibiotics. Its clinical picture varies from a picture of diarrhea to colonic perforation that can determine the performance of an emergency colectomy or even the death of the patient. The certainty diagnosis is carried out by detecting clostridial toxin in fecal matter by enzyme immunoassay techniques. The therapy is carried out with metronidazole or vancomycin orally. Surgical treatment is indicated in the presence of toxic mega colon, intestinal perforation or in those patients with systemic toxicity with failure of medical therapy. (AU)

Spatial organization of Clostridium difficile S-layer biogenesis.

Surface layers (S-layers) are protective protein coats which form around all archaea and most bacterial cells. Clostridium difficile is a Gram-positive bacterium with an S-layer covering its peptidoglycan cell wall. The S-layer in C. difficile is constructed mainly of S-layer protein A (SlpA), which is a key virulence factor and an absolute requirement for disease. S-layer biogenesis is a complex multi-step process, disruption of which has severe consequences for the bacterium. We examined the subcellular localization of SlpA secretion and S-layer growth; observing formation of S-layer at specific sites that coincide with cell wall synthesis, while the secretion of SlpA from the cell is relatively delocalized. We conclude that this delocalized secretion of SlpA leads to a pool of precursor in the cell wall which is available to repair openings in the S-layer formed during cell growth or following damage.

Reuterin disrupts Clostridioides difficile metabolism and pathogenicity through reactive oxygen species generation.

Antibiotic resistance is one of the world's greatest public health challenges and adjunct probiotic therapies are strategies that could lessen this burden. Clostridioides difficile infection (CDI) is a prime example where adjunct probiotic therapies could decrease disease incidence through prevention. Human-derived Lactobacillus reuteri is a probiotic that produces the antimicrobial compound reuterin known to prevent C. difficile colonization of antibiotic-treated fecal microbial communities. However, the mechanism of inhibition is unclear. We show that reuterin inhibits C. difficile outgrowth from spores and vegetative cell growth, however, no effect on C. difficile germination or sporulation was observed. Consistent with published studies, we found that exposure to reuterin stimulated reactive oxygen species (ROS) in C. difficile, resulting in a concentration-dependent reduction in cell viability that was rescued by the antioxidant glutathione. Sublethal concentrations of reuterin enhanced the susceptibility of vegetative C. difficile to vancomycin and metronidazole treatment and reduced toxin synthesis by C. difficile. We also demonstrate that reuterin is protective against C. difficile toxin-mediated cellular damage in the human intestinal enteroid model. Overall, our results indicate that ROS are essential mediators of reuterin activity and show that reuterin production by L. reuteri is compatible as a therapeutic in a clinically relevant model.

[Infection rate and clinical characteristics of toxigenic Clostridium difficile in children with inflammatory bowel disease].

Objective: To explore the infection rate and clinical characteristics of toxigenic Clostridium difficile in children with inflammatory bowel disease (IBD). Methods: From July 2015 to October 2016, the fecal samples and clinical data of 30 IBD children admitted to Department of Gastroenterology, Beijing Children's Hospital, Capital Medical University, as well as the specimens and data of 30 healthy children were collected in the meantime. The toxin gene of Clostridium difficile was detected and clinical characteristics of children with positive toxin gene were analyzed retrospectively. χ(2) test was used to compare the variables between groups. Results: Among the 30 IBD patients, 15 were in ulcerative colitis (UC) group and 15 in Crohn's disease (CD) group. In the IBD group, 6 (3 in UC and 3 in CD group) had positive result of toxigenic Clostridium difficile (20%), among whom 5 were toxin Clostridium difficile A (tcdA) +toxin Clostridium difficile B (tcdB) -, and 1 was tcdA+tcdB+. In the healthy group, only one had positive result of toxigenic Clostridium difficile (3%), which was tcdA+tcdB-. Binary toxin gene was negative in both groups. The infection rate of toxigenic Clostridium difficile in IBD group was significantly higher than that in healthy control group (χ(2)=4.043, P=0.044). In UC group, no Clostridium difficile toxin gene was detected during the remission period (0/1), one case was positive for toxin gene (1/11) during mild active period, and 2 cases were (2/3) during moderately active period. There were significant differences in the infection rate of toxigenic Clostridium difficile between patients in different active period (χ(2)=4.000, P=0.046). The main manifestations of the 6 cases were diarrhea, abdominal pain and bloody stool, and the relapsed case was characterized by sudden aggravation. TcdA was detected in all toxin gene positive samples, and 1 case combined with tcdB had more serious bloody mucopurulent stool. Five cases had colonoscopy, but there was no obvious characteristics of toxigenic Clostridium difficile colitis such as yellow white plaques or pseudomembranous spot. Three cases had antibiotic exposure history. All 6 cases were sensitive to metronidazole treatment, and stable without relapse during the 3-month follow-up. Conclusions: The infection rate of toxigenic Clostridium difficile in children with IBD is higher than that in healthy children. The patients with both tcdA and tcdB could have more serious clinical symptoms, although there may not be specific pathological changes of toxigenic Clostridium difficile colitis. The recognition of toxigenic Clostridium difficile infection in IBD children should be strengthened in clinical work.

The cytotoxic synergy between Clostridioides difficile toxin B and proinflammatory cytokines: an unholy alliance favoring the onset of Clostridioides difficile infection and relapses.

Clostridioides difficile infection (CDI) represents an important health problem worldwide, with significant morbidity and mortality. This infection has also high recurrence rates, whose pathophysiological grounds are still poorly understood. Based on our experiments in vitro with Clostridioides difficile toxin B and existing experimental and clinical evidence, we propose that primary CDI and relapses might be favored by a mechanism that involves the enhancement of the toxicity of toxin B by proinflammatory cytokines, tumor necrosis factor alpha, and interferon gamma on the enteric glial cells and their network in an environment characterized by a strong dysmicrobism.

Identification of the role of toxin B in the virulence of Clostridioides difficile based on integrated bioinformatics analyses.

PURPOSE: Clostridioides difficile toxin B (TcdB) plays a critical role in C. difficile infection (CDI), a common and costly healthcare-associated disease. The aim of the current study was to explore the intracellular and potent systemic effects of TcdB on human colon epithelial cells utilizing Gene Expression Omnibus and bioinformatic methods. METHODS: Two datasets (GSE63880 and GSE29008) were collected to extract data components of mRNA of TcdB-treated human colon epithelial cells; "limma" package of "R" software was used to screen the differential genes, and "pheatmap" package was applied to construct heat maps for the differential genes; Metascape website was utilized for protein-protein interaction network and Molecular Complex Detection analysis, and Genome Ontology (GO) was used to analyze the selected differential genes. Quantitative real-time PCR (qRT-PCR) and Western blot were performed to validate the expression of hub genes. RESULTS: GO terms involved in DNA replication and cell cycle were identified significantly enriched in TcdB-treated human colon epithelial cells. Moreover, the decreased expression of DNA replication-related genes, MCM complex, and CDC45 in C. difficile (TcdA-/TcdB+)-infected Caco-2 cells were validated via qRT-PCR and Western blot assays. CONCLUSIONS: In conclusion, the integrated analysis of different gene expression datasets allowed us to identify a set of genes and GO terms underlying the mechanisms of CDI induced by TcdB. It would aid in understanding of the molecular mechanisms underlying TcdB-exposed colon epithelial cells and provide the basis for developing diagnosis biomarkers, treatment, and prevention strategies.

Immune Profiling To Predict Outcome of Clostridioides difficile Infection.

There is a pressing need for biomarker-based models to predict mortality from and recurrence of Clostridioides difficile infection (CDI). Risk stratification would enable targeted interventions such as fecal microbiota transplant, antitoxin antibodies, and colectomy for those at highest risk. Because severity of CDI is associated with the immune response, we immune profiled patients at the time of diagnosis. The levels of 17 cytokines in plasma were measured in 341 CDI inpatients. The primary outcome of interest was 90-day mortality. Increased tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), C-C motif chemokine ligand 5 (CCL-5), suppression of tumorigenicity 2 receptor (sST-2), IL-8, and IL-15 predicted mortality by univariate analysis. After adjusting for demographics and clinical characteristics, the mortality risk (as indicated by the hazard ratio [HR]) was higher for patients in the top 25th percentile for TNF-α (HR = 8.35, P = 0.005) and IL-8 (HR = 4.45, P = 0.01) and lower for CCL-5 (HR = 0.18, P ≤ 0.008). A logistic regression risk prediction model was developed and had an area under the receiver operating characteristic curve (AUC) of 0.91 for 90-day mortality and 0.77 for 90-day recurrence. While limited by being single site and retrospective, our work resulted in a model with a substantially greater predictive ability than white blood cell count. In conclusion, immune profiling demonstrated differences between patients in their response to CDI, offering the promise for precision medicine individualized treatment.IMPORTANCEClostridioides difficile infection is the most common health care-associated infection in the United States with more than 20% patients experiencing symptomatic recurrence. The complex nature of host-bacterium interactions makes it difficult to predict the course of the disease based solely on clinical parameters. In the present study, we built a robust prediction model using representative plasma biomarkers and clinical parameters for 90-day all-cause mortality. Risk prediction based on immune biomarkers and clinical variables may contribute to treatment selection for patients as well as provide insight into the role of immune system in C. difficile pathogenesis.