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Biofilm formation and toxin production are some of the virulence factors of Clostridioides difficile (C. difficile), which causes hospital-acquired C. difficile infection (HA-CDI). This work investigated the prevalence and distribution of different strains recovered from HA-CDI patients hospitalized in 4 medical centres across Israel, and characterized strains' virulence factors and antibiotic susceptibility. One-hundred and eighty-eight faecal samples were collected. C. difficile 's toxins were detected by the CerTest Clostridium difficile GDH + Toxin A + B combo card test kit. Toxin loci PaLoc and PaCdt were detected by whole-genome sequencing (WGS). Multi-locus sequence typing (MLST) was performed to classify strains. Biofilm production was assessed by crystal violet. Antibiotic susceptibility was determined using Etest. Fidaxomicin susceptibility was tested via agar dilution. Sequence type (ST) 42 was the most (13.8%) common strain. All strains harboured the 2 toxins genes; 6.9% had the binary toxin. Most isolates were susceptible to metronidazole (98.9%) and vancomycin (99.5%). Eleven (5.85%) isolates were fidaxomicin-resistant. Biofilm production capacity was associated with ST (p < 0.001). In conclusion, a broad variety of C. difficile strains circulate in Israel's medical centres. Further studies are needed to explore the differences and their contribution to HA-CDI epidemiology.
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Antibacterianos , Biopelículas , Clostridioides difficile , Infecciones por Clostridium , Infección Hospitalaria , Pruebas de Sensibilidad Microbiana , Factores de Virulencia , Clostridioides difficile/genética , Clostridioides difficile/efectos de los fármacos , Clostridioides difficile/aislamiento & purificación , Clostridioides difficile/patogenicidad , Humanos , Israel/epidemiología , Infecciones por Clostridium/microbiología , Infecciones por Clostridium/epidemiología , Antibacterianos/farmacología , Factores de Virulencia/genética , Masculino , Femenino , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Infección Hospitalaria/microbiología , Infección Hospitalaria/epidemiología , Anciano , Persona de Mediana Edad , Tipificación de Secuencias Multilocus , Adulto , Anciano de 80 o más Años , Secuenciación Completa del Genoma , Heces/microbiologíaRESUMEN
BACKGROUND: Clostridioides difficile infection (CDI) causes substantial mortality and healthcare burden. We assessed the detoxified toxin-A/B PF-06425090 vaccine for primary CDI prevention. METHODS: This phase 3 observer-blinded study randomized (1:1) ≥50-year-olds at increased CDI risk (N=17,535) to receive 3 PF-06425090 or placebo doses (0,1,6-months). Primary endpoints were first CDI episode (≥3 unformed stools within 24 hours; central laboratory-confirmed toxin A/B positive) ≥14 days post-dose 3 (PD3; first primary) and post-dose 2 (PD2; second primary). CDI duration, need for CDI-related medical attention (secondary endpoints), and antibiotic use (post hoc analysis) PD3 were evaluated. Tolerability/safety was assessed. RESULTS: The primary endpoint was not met (17 PF-06425090 and 25 placebo recipients had first CDI episode ≥14 days PD3 [vaccine efficacy (VE)=31.0% (96.4%CI: -38.7%-66.6%)]; 24 PF-06425090 and 34 placebo recipients had first CDI episode ≥14 days PD2 [VE=28.6% (-28.4%-61.0%)]). Median CDI duration was lower with PF-06425090 (1 day) versus placebo (4 days; 2-sided nominal P=0.02). Of participants with first CDI episode, 0 PF-06425090 and 11 placebo recipients sought CDI-related medical attention (post hoc analysis estimated VE=100% [95%CI: 59.6%-100.0%]) and 0 PF-06425090 and 10 placebo recipients required antibiotic treatment (VE=100% [54.8%-100.0%]). Local reactions were more frequent in PF-06425090 recipients and systemic events were generally similar between groups; most were mild-to-moderate. AE rates were similar between groups. CONCLUSIONS: Three PF-06425090 doses were safe and well-tolerated. Although the primary endpoint was not met, PF-06425090 reduced symptom duration, CDI requiring medical attention, and CDI-directed antibiotic treatment, highlighting its potential to reduce CDI-associated healthcare burden. NCT03090191.
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Glycogen plays a vital role as an energy reserve in various bacterial and fungal species. Clostridioides difficile possesses a glycogen metabolism operon that contains genes for both glycogen synthesis and utilization. In our investigation, we focused on understanding the significance of glycogen metabolism in the physiology and pathogenesis of C. difficile. To explore this, we engineered a C. difficile JIR8094 strain lacking glycogen synthesis capability by introducing a group II intron into the glgC gene, the operon's first component. Quantification of intracellular glycogen levels validated the impact of this modification. Interestingly, the mutant strain exhibited a 1.5-fold increase in toxin production compared with the parental strain, without significant changes in the sporulation rate. Our analysis also revealed that wild-type C. difficile spores contained glycogen, whereas spores from the mutant strain lacking stored glycogen showed increased sensitivity to physical and chemical treatments and had a shorter storage life. By suppressing glgP expression, the gene coding for glycogen-phosphorylase, via CRISPRi, we demonstrated that glycogen accumulation but not the utilization is needed for spore resilience in C. difficile. Transmission electron microscopy analysis revealed a significantly lower core/cortex ratio in glgC mutant strain spores. In hamster challenge experiments, both the parental and glgC mutant strains colonized hosts similarly; however, the mutant strain failed to induce infection relapse after antibiotic treatment cessation. These findings highlight the importance of glycogen metabolism in C. difficile spore resilience and suggest its role in disease relapse.IMPORTANCEThis study on the role of glycogen metabolism in Clostridioides difficile highlights its critical involvement in the pathogen's energy management, its pathogenicity, and its resilience. Our results also revealed that glycogen presence in spores is pivotal for their structural integrity and resistance to adverse conditions, which is essential for their longevity and infectivity. Importantly, the inability of the mutant strain to cause infection relapse in hamsters post-antibiotic treatment pinpoints a potential target for therapeutic interventions, highlighting the importance of glycogen in disease dynamics. This research thus significantly advances our understanding of C. difficile physiology and pathogenesis, offering new avenues for combating its persistence and recurrence.
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Most bacteria are surrounded by a cell wall that contains peptidoglycan (PG), a large polymer composed of glycan strands held together by short peptide cross-links. There are two major types of cross-links, termed 4-3 and 3-3 based on the amino acids involved. 4-3 cross-links are created by penicillin-binding proteins, while 3-3 cross-links are created by L,D-transpeptidases (LDTs). In most bacteria, the predominant mode of cross-linking is 4-3, and these cross-links are essential for viability, while 3-3 cross-links comprise only a minor fraction and are not essential. However, in the opportunistic intestinal pathogen Clostridioides difficile, about 70% of the cross-links are 3-3. We show here that 3-3 cross-links and LDTs are essential for viability in C. difficile. We also show that C. difficile has five LDTs, three with a YkuD catalytic domain as in all previously known LDTs and two with a VanW catalytic domain, whose function was until now unknown. The five LDTs exhibit extensive functional redundancy. VanW domain proteins are found in many gram-positive bacteria but scarce in other lineages. We tested seven non-C. difficile VanW domain proteins and confirmed LDT activity in three cases. In summary, our findings uncover a previously unrecognized family of PG cross-linking enzymes, assign a catalytic function to VanW domains, and demonstrate that 3-3 cross-linking is essential for viability in C. difficile, the first time this has been shown in any bacterial species. The essentiality of LDTs in C. difficile makes them potential targets for antibiotics that kill C. difficile selectively.
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Proteínas Bacterianas , Pared Celular , Clostridioides difficile , Peptidoglicano , Clostridioides difficile/enzimología , Clostridioides difficile/metabolismo , Peptidoglicano/metabolismo , Pared Celular/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Peptidoglicano Glicosiltransferasa/metabolismo , Peptidoglicano Glicosiltransferasa/química , Peptidoglicano Glicosiltransferasa/genéticaRESUMEN
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.
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Clostridioides difficile is an emerging pathogen of One Health significance. Its highly variable genome contains mobile genetic elements (MGEs) such as transposons and prophages that influence its biology. Systematic deletion of each genetic element is required to determine their precise role in C. difficile biology and contribution to the wider mobilome. Here, Tn5397 (21 kb) and Ï027 (56 kb) were deleted from C. difficile 630 and R20291, respectively, using allele replacement facilitated by CRISPR-Cas9. The 630 Tn5397 deletant transferred PaLoc at the same frequency (1 × 10-7) as 630 harboring Tn5397, indicating that Tn5397 alone did not mediate conjugative transfer of PaLoc. The R20291 Ï027 deletant was sensitive to Ï027 infection, and contained two unexpected features, a 2.7 kb remnant of the mutagenesis plasmid, and a putative catalase gene adjacent to the deleted prophage was also deleted. Growth kinetics of R20291 Ï027 deletant was similar to wild type (WT) in rich medium but marginally reduced compared with WT in minimal medium. This work indicates the commonly used pMTL8000 plasmid series works well for CRISPR-Cas9-mediated gene deletion, resulting in the largest deleted locus (56.8 kb) described in C. difficile. Removal of MGEs was achieved by targeting conjugative/integrative regions to promote excision and permanent loss. The deletants created will be useful strains for investigating Tn5397 or Ï027 prophage contribution to host virulence, fitness, and physiology, and a platform for other mutagenesis studies aimed at functional gene analysis without native transposon or phage interference in C. difficile 630 and R20291.
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Fecal microbiota transplantation is an evidence-based therapeutic option for recurrent Clostridium difficile infection, involving the transfer of healthy donor fecal material to restore gut microbial balance. Despite meticulous donor screening, Campylobacter jejuni, a prevalent cause of bacterial gastroenteritis, is not routinely tested, potentially impacting fecal microbiota transplant safety. We present a case of a female with recurrent C. difficile infection treated with fecal microbiota transplantation, complicated by a subsequent C. jejuni infection. The emergence of Campylobacter post fecal microbiota transplantation underscores the importance of comprehensive donor screening protocols. Our case prompts a reevaluation of fecal microbiota transplantation safety measures and advocates for inclusive screening to enhance patient outcomes.
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Background: Hematopoietic cell transplantation (HCT) recipients are at increased risk of developing primary and recurrent Clostridioides difficile infection (CDI). The objective of our study was to characterize the risk factors for primary and recurrent CDI in a large cohort of patients hospitalized for HCT. Methods: We conducted a retrospective cohort study of adults who underwent HCT from 2010-2023 to analyze the epidemiology, timing, and risk factors for CDI. We compared patients who developed CDI with those who did not, controlling for patient demographics, comorbidities, transplant factors, medications, and laboratory values. Results: Of the 2,725 adults who underwent HCT, 252 (9.3%) developed primary CDI within one-year of transplantation. The incidence was higher among allogenic HCT recipients (17.8%) compared to autologous recipients (4.1%). Independent risk factors for primary CDI included receipt of penicillin antibiotics, prior chemotherapy, and umbilical cord stem cells. Receipt of macrolide antibiotics was an independent risk factor for recurrent CDI, while receipt of autologous HCT was associated with a reduced risk of both primary and recurrent CDI. Conclusions: CDI presents an early complication after HCT, particularly in allogenic recipients who experience higher incidence rates and severe complications. Early recognition and management of these risk factors are essential to prevent these adverse outcomes.
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There is an unmet need for effective treatments of Clostridioides difficile infection, an emerging health crisis in the United States. The management of C. difficile infection should include treatment of active infection and a strategy to prevent recurrence. Current gold standard therapy includes oral antibiotics which predispose patients to gut dysbiosis and increase the risk of recurrent infection. Addressing dysbiosis via fecal microbiota transplantation is an active and promising area of research, but studies have lacked standardization which makes outcome and safety data difficult to interpret. Rebyota™, formerly known as RBX2660, is a live biotherapeutic product designed using a standardized protocol and manufacturing process that has been shown to be effective for preventing recurrent C. difficile infection.
Clostridioides difficile infection is becoming more common in the USA and causes profuse diarrhea that can be deadly. Treatment with antibiotics causes dysregulation of the bacteria in the gut putting patients at a higher risk of reinfection. Fecal microbiota live jslm is a new therapy approved by the US FDA that uses stool from healthy donors to return gut bacteria levels to normal after treatment for a C. diff infection.
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Food and Drug Administration approval of the first microbiome therapies represents a true expansion the treatment paradigm for Clostridioides difficile but raises new questions about the future role of fecal microbiota transplantation. The authors outline the advances in microbiome therapeutic development that have addressed fecal microbiota transplantation's (FMT's) inherent limitations of safety and scalability. The authors also suggest that as microbiome therapeutic development continues for other indications, FMT will likely remain a necessary model of human microbiota dynamics for translational research.
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Clostridioides difficile , Infecciones por Clostridium , Trasplante de Microbiota Fecal , Microbioma Gastrointestinal , Humanos , Trasplante de Microbiota Fecal/métodos , Infecciones por Clostridium/terapia , Infecciones por Clostridium/microbiología , Estados Unidos , Microbiota , United States Food and Drug AdministrationRESUMEN
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.
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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.
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Clostridioides difficile, a Gram-positive anaerobic bacterium, is the leading cause of hospital-acquired antibiotic-associated diarrhea worldwide. The severity of C. difficile infection (CDI) varies, ranging from mild diarrhea to life-threatening conditions such as pseudomembranous colitis and toxic megacolon. Central to the pathogenesis of the infection are toxins produced by C. difficile, with toxin A (TcdA) and toxin B (TcdB) as the main virulence factors. Additionally, some strains produce a third toxin known as C. difficile transferase (CDT). Toxins damage the colonic epithelium, initiating a cascade of cellular events that lead to inflammation, fluid secretion, and further tissue damage within the colon. Mechanistically, the toxins bind to cell surface receptors, internalize, and then inactivate GTPase proteins, disrupting the organization of the cytoskeleton and affecting various Rho-dependent cellular processes. This results in a loss of epithelial barrier functions and the induction of cell death. The third toxin, CDT, however, functions as a binary actin-ADP-ribosylating toxin, causing actin depolymerization and inducing the formation of microtubule-based protrusions. In this review, we summarize our current understanding of the interaction between C. difficile toxins and host cells, elucidating the functional consequences of their actions. Furthermore, we will outline how this knowledge forms the basis for developing innovative, toxin-based strategies for treating and preventing CDI.
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Toxinas Bacterianas , Clostridioides difficile , Interacciones Microbiota-Huesped , Clostridioides difficile/genética , Clostridioides difficile/patogenicidad , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Toxinas Bacterianas/inmunología , Infecciones por Clostridium/tratamiento farmacológico , Infecciones por Clostridium/microbiología , Infecciones por Clostridium/patología , Orden Génico , Inflamación/patología , Humanos , AnimalesRESUMEN
Gut microbiota dysbiosis increases the susceptibility to Clostridioides difficile infection (CDI). In this study, we monitored C. difficile colonization (CDC) patients from no CDC status (CDN) to CDC status (CDCp) and CDI patients from asymptomatic status before CDI (PRECDI), CDI status (ONCDI), to asymptomatic status after CDI (POSTCDI). Based on metagenomic sequencing, we aimed to investigate the interaction pattern between gut microbiota and C. difficile. There was no significant difference of microbiota diversity between CDN and CDCp. In CDCp, Bacteroidetes and short-chain fatty acid (SCFA)-producing bacteria increased, with a positive correlation between SCFA-producing bacteria and C. difficile colonization. Compared with PRECDI, ONCDI and POSTCDI showed a significant decrease in microbiota diversity, particularly in Bacteroidetes and SCFA-producing bacteria, with a positive correlation between opportunistic pathogen and C. difficile. Fatty acid metabolism, and amino acid biosynthesis were enriched in CDN, CDCp, and PRECDI, while bile secretion was enriched in ONCDI and POSTCDI. Microbiota and metabolic pathways interaction networks in CDN and CDCp were more complex, particularly pathways in fatty acid and bile acid metabolism. Increasing of Bacteroidetes and SCFA-producing bacteria, affecting amino acid and fatty acid metabolism, is associated with colonization resistance to C. difficile and inhibiting the development of CDI.
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BACKGROUND: C. difficile has been increasingly reported as a cause of gastrointestinal disease in children, ranging from mild self-limiting diarrhea to severe conditions such as pseudomembranous colitis and toxic megacolon. Only two pediatric research groups reported the presence of C. difficile infection in Brazilian children, but no previous research has examined C. difficile infection among children in northeastern Brazil. This prospective cross-sectional study investigated the molecular epidemiology and antimicrobial resistance of C. difficile strains isolated from children and adolescents with diarrhea referred to a tertiary pediatric hospital in Brazil while exploring the associated risk factors. RESULTS: Toxin positivity or C. difficile isolation was found in 30.4 % (17/56) samples. C. difficile was isolated from 35 % (6/17) samples. Four toxigenic strains were identified (tpi+, tcdA+, tcdB+, cdtB-, without tcdC deletions) belonging to PCR ribotypes and PFGE-pulsotypes: 046 (new pulsotype 1174), 106 (NAP11), 002 (new pulsotype 1274), 012 (new pulsotype NML-1235). Two of the six isolates belonging to ribotypes 143 and 133 were non-toxigenic. All toxigenic strains were sensitive to metronidazole and vancomycin. Regarding the clinical manifestation, diarrhea lasted an average of 11 days, ranging from 3 to 50 days and was often associated with mucus and/or blood. All six patients from whom the C. difficile was isolated had a chronic disease diagnosis, with these comorbidities as the main risk factors. CONCLUSION: Our study enhances our understanding of the present epidemiological landscape of C. difficile-associated diarrhea (CDI) among children in northeastern Brazil, reveling a substantial CDI frequency of 30.4 %, with toxigenic strains detected in 76.4 % of cases, highlighting a higher prevalence compared to earlier Brazilian studies. In the globalized world, an understanding of disease-generating strains, the associated risk factors, clinical manifestation, and antimicrobial sensitivity has fundamental epidemiological importance and draws attention to preventive measures, allowing for more decisive action.
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Antibacterianos , Clostridioides difficile , Infecciones por Clostridium , Hospitales Pediátricos , Pruebas de Sensibilidad Microbiana , Centros de Atención Terciaria , Humanos , Clostridioides difficile/genética , Clostridioides difficile/efectos de los fármacos , Clostridioides difficile/aislamiento & purificación , Niño , Adolescente , Femenino , Masculino , Brasil/epidemiología , Estudios Transversales , Estudios Prospectivos , Centros de Atención Terciaria/estadística & datos numéricos , Preescolar , Antibacterianos/farmacología , Infecciones por Clostridium/epidemiología , Infecciones por Clostridium/microbiología , Factores de Riesgo , Lactante , Epidemiología Molecular , Diarrea/microbiología , Diarrea/epidemiología , Ribotipificación , Farmacorresistencia Bacteriana/genéticaRESUMEN
Recurrent Clostridioides difficile infection (CDI) results in significant morbidity and mortality. We previously established that CDI in mice does not protect against reinfection and is associated with poor pathogen-specific B cell memory (Bmem), recapitulating our observations with human Bmem. Here, we demonstrate that the secreted toxin TcdB2 is responsible for subversion of Bmem responses. TcdB2 from an endemic C. difficile strain delayed immunoglobulin G (IgG) class switch following vaccination, attenuated IgG recall to a vaccine booster, and prevented germinal center formation. The mechanism of TcdB2 action included increased B cell CXCR4 expression and responsiveness to its ligand CXCL12, accounting for altered cell migration and a failure of germinal center-dependent Bmem. These results were reproduced in a C. difficile infection model, and a US Food and Drug Administration (FDA)-approved CXCR4-blocking drug rescued germinal center formation. We therefore provide mechanistic insights into C. difficile-associated pathogenesis and illuminate a target for clinical intervention to limit recurrent disease.
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Proteínas Bacterianas , Toxinas Bacterianas , Clostridioides difficile , Centro Germinal , Receptores CXCR4 , Animales , Receptores CXCR4/metabolismo , Receptores CXCR4/inmunología , Centro Germinal/inmunología , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/inmunología , Toxinas Bacterianas/inmunología , Toxinas Bacterianas/metabolismo , Clostridioides difficile/inmunología , Clostridioides difficile/patogenicidad , Ratones , Ratones Endogámicos C57BL , Linfocitos B/inmunología , Linfocitos B/metabolismo , Quimiocina CXCL12/metabolismo , Infecciones por Clostridium/inmunología , Infecciones por Clostridium/microbiología , Humanos , Inmunoglobulina G/inmunología , Inmunoglobulina G/metabolismo , Memoria Inmunológica , Femenino , Formación de Anticuerpos/inmunologíaRESUMEN
BACKGROUND: Antibiotics are a strong risk factor for Clostridioides difficile infection (CDI), and CDI incidence is often measured as an important outcome metric for antimicrobial stewardship interventions aiming to reduce antibiotic use. However, risk of CDI from antibiotics varies by agent and dependent on the intensity (i.e., spectrum and duration) of antibiotic therapy. Thus, the impact of stewardship interventions on CDI incidence is variable, and understanding this risk requires a more granular measure of intensity of therapy than traditionally used measures like days of therapy (DOT). METHODS: We performed a retrospective cohort study to measure the independent association between intensity of antibiotic therapy, as measured by the antibiotic spectrum index (ASI), and hospital-associated CDI (HA-CDI) at a large academic medical center between January 2018 and March 2020. We constructed a marginal Poisson regression model to generate adjusted relative risks for a unit increase in ASI per antibiotic day. RESULTS: We included 35,457 inpatient encounters in our cohort. Sixty-eight percent of patients received at least one antibiotic. We identified 128 HA-CDI cases, which corresponds to an incidence rate of 4.1 cases per 10,000 patient-days. After adjusting for known confounders, each additional unit increase in ASI per antibiotic day is associated with 1.09 times the risk of HA-CDI (Relative Risk = 1.09, 95% Confidence Interval: 1.06 to 1.13). CONCLUSIONS: ASI was strongly associated with HA-CDI and could be a useful tool in evaluating the impact of antibiotic stewardship on HA-CDI rates, providing more granular information than the more commonly used days of therapy.
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Clostridioides difficile (C. difficile), as the major pathogen of diarrhea in healthcare settings, has become increasingly prevalent within community populations, resulting in significant morbidity and mortality. However, the therapeutic options for Clostridioides difficile infection (CDI) remain limited, and as of now, no authorized vaccine is available to combat this disease. Therefore, the development of a novel vaccine against C. difficile is of paramount importance. In our study, the complete proteome sequences of 118 strains of C. difficile were downloaded and analyzed. We found four antigenic proteins that were highly conserved and can be used for epitope identification. We designed two vaccines, WLcd1 and WLcd2, that contain the ideal T-cell and B-cell epitopes, adjuvants, and the pan HLA DR-binding epitope (PADRE) sequences. The biophysical and chemical assessments of these vaccine candidates indicated that they were suitable for immunogenic applications. Molecular docking analyses revealed that WLcd1 bonded with higher affinity to Toll-like receptors (TLRs) than WLcd2. Furthermore, molecular dynamics (MD) simulations, performed using Gmx_MMPBSA v1.56, confirmed the binding stability of WLcd1 with TLR2 and TLR4. The preliminary findings suggested that this multi-epitope vaccine could be a promising candidate for protection against CDI; however, experimental studies are necessary to confirm these predictions.
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Clostridioides difficile (C. difficile) strains belonging to the epidemic BI/NAP1/027 (RT027) group have been associated with increased transmissibility and disease severity. In addition to the major toxin A and toxin B virulence factors, RT027 strains also encode the CDT binary toxin. Our lab previously identified a toxigenic RT027 isolate, ST1-75, that is avirulent in mice despite densely colonizing the colon. Here, we show that coinfecting mice with the avirulent ST1-75 and virulent R20291 strains protects mice from colitis due to rapid clearance of the virulent strain and persistence of the avirulent strain. Although avirulence of ST1-75 is due to a mutation in the cdtR gene, which encodes a response regulator that modulates the production of all three C. difficile toxins, the ability of ST1-75 to protect against acute colitis is not directly attributable to the cdtR mutation. Metabolomic analyses indicate that the ST1-75 strain depletes amino acids more rapidly than the R20291 strain and supplementation with amino acids ablates ST1-75's competitive advantage, suggesting that the ST1-75 strain limits the growth of virulent R20291 bacteria by amino acid depletion. Since the germination kinetics and sensitivity to the co-germinant glycine are similar for the ST1-75 and R20291 strains, our results identify the rapidity of in vivo nutrient depletion as a mechanism providing strain-specific, virulence-independent competitive advantages to different BI/NAP1/027 strains. They also suggest that the ST1-75 strain may, as a biotherapeutic agent, enhance resistance to CDI in high-risk patients.
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OBJECTIVES: Clostridioides difficile infection (CDI) is the leading hospital-acquired infection in North America. We have previously discovered that antibiotic disruption of the gut microbiota decreases intestinal IL-33 and IL-25 and increases susceptibility to CDI. We further found that IL-33 promotes protection through type 2 Innate Lymphoid Cells (ILC2s), which produce IL-13. However, the contribution of IL-13 to disease has never been explored. METHODS: We used a validated model of CDI in mice, in which we neutralized via blocking antibodies, or administered recombinant protein, IL-13 to assess the role of this cytokine during infection using weight and clinical scores. Fluorescent activated cell sorting (FACS) was used to characterize myeloid cell population changes in response to IL-13 manipulation. RESULTS: We found that administration of IL-13 protected, and anti-IL-13 exacerbated CDI. Additionally, we observed alterations to the monocyte/macrophage cells following neutralization of IL-13 as early as day three post infection. We also observed elevated accumulation of myeloid cells by day four post-infection following IL-13 neutralization. Neutralization of the decoy receptor, IL-13Rα2, resulted in protection from disease, likely through increased available endogenous IL-13. CONCLUSIONS: Our data highlight the protective role of IL-13 in protecting from more severe CDI and the association of poor responses with a dysregulated monocyte-macrophage compartment. These results increase our understanding of type 2 immunity in CDI and may have implications for treating disease in patients.