scholarly journals EPIDEMIC RIBOTYPES OF CLOSTRIDIUM (NOW CLOSTRIDIOIDES) DIFFICILE ARE LIKELY TO BE MORE VIRULENT THAN NON-EPIDEMIC RIBOTYPES IN ANIMAL MODELS

2020 ◽  
Author(s):  
John C. Vitucci ◽  
Mark Pulse ◽  
Leslie Tabor-Simecka ◽  
Jerry W. Simecka
Keyword(s):  
Animal Models ◽  
Toxin Production ◽  
Intestinal Epithelial ◽  
Toxin B ◽  
Golden Syrian Hamster ◽  
Clostridioides Difficile ◽  
Conflicting Evidence ◽  
Epithelial Cell Lines

Abstract Background . Clostridioides difficile infections have become more frequently diagnosed and associated with greater disease severity, which has resulted in an increase burden on the healthcare system. These increases are attributed to the increased prevalence of hypervirulent strains encompassing select ribotypes. These epidemic ribotypes were characterized as hypervirulent due to higher in vitro spore and toxin production, as well as increased incidence, severity and mortality within patients. However, it is unclear whether epidemic ribotypes are truly more virulent than non-epidemic ribotypes in vivo. Furthermore, there is conflicting evidence about the ability of a strain’s in vitro phenotype to be predictive of their in vivo virulence. The goals of the current studies were to determine if epidemic ribotypes are more virulent than other ribotypes in animal models, and whether the in vitro virulence phenotype of an isolate or ribotype predict in vivo virulence. Results. To determine if epidemic strains were truly more virulent than other non-epidemic strains, the in vivo virulence of thirteen C. difficile isolates (7 non-epidemic and 6 epidemic ribotype isolates) were determined in murine (C57BL/6 mice) and hamster (golden Syrian hamster) models of C. difficile infections. The isolates of epidemic ribotype of C. difficile were found to be more virulent in both the murine and hamster models than non-epidemic isolates. In particular, the group of epidemic ribotypes of C. difficile had lower LD 50 values in hamsters. The increased severity of disease was associated with higher levels of Toxin A and Toxin B production found in fecal samples, but not numbers of organisms recovered. The isolates were further characterized for their in vitro virulence phenotypes, e.g. toxin production, growth rates, spore formation and adherence of spores to intestinal epithelial cell lines. Although there were higher levels of toxins produced and greater adherence for the group of epidemic ribotypes, the in vitro profiles of individual isolates were not always predictive of their in vivo virulence. Conclusions. Overall, the group of epidemic ribotypes of C. difficile were more virulent in vivo despite individual isolates having similar phenotypes to the non-epidemic isolates in vitro .

scholarly journals Epidemic Ribotypes Of Clostridium (Now Clostridioides) Difficile Are Likely To Be More Virulent Than Non-Epidemic Ribotypes In Animal Models

2019 ◽  
Author(s):  
John C. Vitucci ◽  
Mark Pulse ◽  
Leslie Tabor-Simecka ◽  
Jerry W. Simecka
Keyword(s):  
Animal Models ◽  
Toxin Production ◽  
Intestinal Epithelial ◽  
Toxin B ◽  
Golden Syrian Hamster ◽  
Clostridioides Difficile ◽  
Conflicting Evidence ◽  
Epithelial Cell Lines

Abstract Background: Clostridioides difficile infections have become more frequently diagnosed and associated with greater disease severity, which has resulted in an increase burden on the healthcare system. These increases are attributed to the increased prevalence of hypervirulent strains encompassing select ribotypes. These epidemic ribotypes were characterized as hypervirulent due to higher in vitro spore and toxin production, as well as increased incidence, severity and mortality within patients. However, it is unclear whether epidemic ribotypes are truly more virulent than non-epidemic ribotypes in vivo. Furthermore, there is conflicting evidence about the ability of a strain’s in vitro phenotype to be predictive of their in vivo virulence. The goals of the current studies were to determine if epidemic ribotypes are more virulent than other ribotypes in animal models, and whether the in vitro virulence phenotype of an isolate or ribotype predict in vivo virulence. Results. To determine if epidemic strains were truly more virulent than other non-epidemic strains, the in vivo virulence of thirteen C. difficile isolates (7 non-epidemic and 6 epidemic ribotype isolates) were determined in murine (C57BL/6 mice) and hamster (golden Syrian hamster) models of C. difficile infections. The isolates of epidemic ribotype of C. difficile were found to be more virulent in both the murine and hamster models than non-epidemic isolates. In particular, the group of epidemic ribotypes of C. difficile had lower LD 50 values in hamsters. The increased severity of disease was associated with higher levels of Toxin A and Toxin B production found in fecal samples, but not numbers of organisms recovered. The isolates were further characterized for their in vitro virulence phenotypes, e.g. toxin production, growth rates, spore formation and adherence of spores to intestinal epithelial cell lines. Although there were higher levels of toxins produced and greater adherence for the group of epidemic ribotypes, the in vitro profiles of individual isolates were not always predictive of their in vivo virulence. Conclusions. Overall, the group of epidemic ribotypes of C. difficile were more virulent in vivo despite individual isolates having similar phenotypes to the non-epidemic isolates in vitro .

scholarly journals Epidemic Ribotypes Of Clostridium (Now Clostridioides) Difficile Are Likely To Be More Virulent Than Non-epidemic Ribotypes In Animal Models

2019 ◽  
Author(s):  
John C. Vitucci ◽  
Mark Pulse ◽  
Leslie Tabor-Simecka ◽  
Jerry W. Simecka
Keyword(s):  
Animal Models ◽  
Toxin Production ◽  
Intestinal Epithelial ◽  
Toxin B ◽  
Golden Syrian Hamster ◽  
Clostridioides Difficile ◽  
Conflicting Evidence ◽  
Epithelial Cell Lines

Abstract Background. Clostridium difficile infections have become more frequently diagnosed and associated with greater disease severity, which has resulted in an increase burden on the healthcare system. These increases are attributed to the increased prevalence of hypervirulent strains encompassing select ribotypes. These epidemic ribotypes were characterized as hypervirulent due to higher in vitro spore and toxin production, as well as increased incidence, severity and mortality within patients. However, it is unclear whether epidemic ribotypes are truly more virulent than non-epidemic ribotypes in vivo. Furthermore, there is conflicting evidence about the ability of a strain’s in vitro phenotype to be predictive of their in vivo virulence. The goals of the current studies were to determine if epidemic ribotypes are more virulent than other ribotypes in animal models, and whether the in vitro virulence phenotype of an isolate or ribotype predict in vivo virulence. Results. To determine if epidemic strains were truly more virulent than other non-epidemic strains, the in vivo virulence of thirteen C. difficile isolates (7 non-epidemic and 6 epidemic ribotype isolates) were determined in murine (C57BL/6 mice) and hamster (golden Syrian hamster) models of C. difficile infections. The isolates of epidemic ribotype of C. difficile were found to be more virulent in both the murine and hamster models than non-epidemic isolates. In particular, the group of epidemic ribotypes of C. difficile had lower LD50 values in hamsters. The increased severity of disease was associated with higher levels of Toxin A and Toxin B production found in fecal samples, but not numbers of organisms recovered. The isolates were further characterized for their in vitro virulence phenotypes, e.g. toxin production, growth rates, spore formation and adherence of spores to intestinal epithelial cell lines. Although there were higher levels of toxins produced and greater adherence for the group of epidemic ribotypes, the in vitro profiles of individual isolates were not always predictive of their in vivo virulence. Conclusions. Overall, the group of epidemic ribotypes of C. difficile were more virulent in vivo despite individual isolates having similar phenotypes to the non-epidemic isolates in vitro.

scholarly journals Toxin A–Predominant Pathogenic Clostridioides difficile: A Novel Clinical Phenotype

2019 ◽  
Vol 70 (12) ◽  
pp. 2628-2633 ◽  
Author(s):  
Qianyun Lin ◽  
Nira R Pollock ◽  
Alice Banz ◽  
Aude Lantz ◽  
Hua Xu ◽  
...  
Keyword(s):  
Vaccine Development ◽  
Toxin Production ◽  
Toxin A ◽  
Toxin B ◽  
Clostridioides Difficile ◽  
Quantitative Immunoassay ◽  
Clinical Detection ◽  
Stool Samples

Abstract Background Most Clostridioides difficile toxinogenic strains produce both toxins A and B (A+B+), but toxin A–negative, toxin B–positive (A−B+) variants also cause disease. We report the identification of a series of pathogenic clinical C. difficile isolates that produce high amounts of toxin A with low or nondetectable toxin B. Methods An ultrasensitive, quantitative immunoassay was used to measure toxins A and B in stool samples from 187 C. difficile infection (CDI) patients and 44 carriers. Isolates were cultured and assessed for in vitro toxin production and in vivo phenotypes (mouse CDI model). Results There were 7 CDI patients and 6 carriers who had stools with detectable toxin A (TcdA, range 23–17 422 pg/mL; 5.6% of samples overall) but toxin B (TcdB) below the clinical detection limit (<20 pg/mL; median TcdA:B ratio 17.93). Concentrations of toxin A far exceeded B in in vitro cultures of all 12 recovered isolates (median TcdA:B ratio 26). Of 8 toxin A>>B isolates tested in mice, 4 caused diarrhea, and 3 of those 4 caused lethal disease. Ribotyping demonstrated strain diversity. TcdA-predominant samples were also identified at 2 other centers, with similar frequencies (7.5% and 6.8%). Conclusions We report the discovery of clinical pathogenic C. difficile strains that produce high levels of toxin A but minimal or no toxin B. This pattern of toxin production is not rare (>5% of isolates) and is consistently observed in vitro and in vivo in humans and mice. Our study highlights the significance of toxin A in human CDI pathogenesis and has important implications for CDI diagnosis, treatment, and vaccine development.

scholarly journals Alimentary and Pharmaceutical Approach to Natural Antimicrobials against Clostridioides difficile Gastrointestinal Infection

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1124
Author(s):  
Miguel Tortajada-Girbés ◽  
Alejandro Rivas ◽  
Manuel Hernández ◽  
Ana González ◽  
Maria A. Ferrús ◽  
...  
Keyword(s):  
Toxin Production ◽  
Gastrointestinal Infection ◽  
Natural Antimicrobials ◽  
Gastrointestinal Microbiome ◽  
Clostridioides Difficile ◽  
Clostridioides Difficile Infection ◽  
Successful Control ◽  
Marine Bioactives

Incidence of Clostridioides difficile infection (CDI) has been increasing in recent decades due to different factors, namely (i) extended use of broad-spectrum antibiotics, (ii) transmission within asymptomatic and susceptible patients, and (iii) unbalanced gastrointestinal microbiome and collateral diseases that favor C. difficile gastrointestinal domination and toxin production. Although antibiotic therapies have resulted in successful control of CDI in the last 20 years, the development of novel strategies is urged in order to combat the capability of C. difficile to generate and acquire resistance to conventional treatments and its consequent proliferation. In this regard, vegetable and marine bioactives have emerged as alternative and effective molecules to fight against this concerning pathogen. The present review examines the effectiveness of natural antimicrobials from vegetable and algae origin that have been used experimentally in in vitro and in vivo settings to prevent and combat CDI. The aim of the present work is to contribute to accurately describe the prospective use of emerging antimicrobials as future nutraceuticals and preventive therapies, namely (i) as dietary supplement to prevent CDI and reduce CDI recurrence by means of microbiota modulation and (ii) administering them complementarily to other treatments requiring antibiotics to prevent C. difficile gut invasion and infection progression.

scholarly journals Flagellum and toxin phase variation impacts intestinal colonization and disease development in a mouse model of Clostridioides difficile infection

2021 ◽  
Author(s):  
Dominika Trzilova ◽  
Mercedes A. H. Warren ◽  
Nicole C. Gadda ◽  
Caitlin L. Williams ◽  
Rita Tamayo
Keyword(s):  
Mouse Model ◽  
Dna Recombination ◽  
Phase Variation ◽  
Toxin Production ◽  
Disease Development ◽  
Hamster Model ◽  
Clostridioides Difficile ◽  
The Right

AbstractClostridioides difficile is a major nosocomial pathogen that can cause severe, toxin-mediated diarrhea and pseudomembranous colitis. Recent work has shown that C. difficile exhibits heterogeneity in swimming motility and toxin production in vitro through phase variation by site-specific DNA recombination. The recombinase RecV reversibly inverts the flagellar switch sequence upstream of the flgB operon, leading to the ON/OFF expression of flagellum and toxin genes. How this phenomenon impacts C. difficile virulence in vivo remains unknown. We identified mutations in the right inverted repeat that reduced or prevented flagellar switch inversion by RecV. We introduced these mutations into C. difficile R20291 to create strains with the flagellar switch “locked” in either the ON or OFF orientation. These mutants exhibited a loss of flagellum and toxin phase variation during growth in vitro, yielding precisely modified mutants suitable for assessing virulence in vivo. In a hamster model of acute C. difficile infection, the phase-locked ON mutant caused greater toxin accumulation than the phase locked OFF mutant but did not differ significantly in the ability to cause acute disease symptoms. In contrast, in a mouse model, preventing flagellum and toxin phase variation affected the ability of C. difficile to colonize the intestinal tract and to elicit weight loss, which is attributable to differences in toxin production during infection. These results show that the ability of C. difficile to phase vary flagella and toxins influences colonization and disease development and suggest that the phenotypic variants generated by flagellar switch inversion have distinct capacities for causing disease.

scholarly journals Selection of Bifidobacteria Based on Adhesion and Anti-Inflammatory Capacity In Vitro for Amelioration of Murine Colitis

2010 ◽  
Vol 76 (9) ◽  
pp. 3048-3051 ◽  
Author(s):  
Julia Preising ◽  
David Philippe ◽  
Marita Gleinser ◽  
Hua Wei ◽  
Stephanie Blum ◽  
...  
Keyword(s):  
Intestinal Epithelial Cell ◽  
Bifidobacterium Bifidum ◽  
Intestinal Epithelial ◽  
Murine Models ◽  
Murine Colitis ◽  
Epithelial Cell Lines ◽  
Anti Inflammatory ◽  
Selection Of

ABSTRACT Adhesion and anti-inflammatory properties of eight strains of bifidobacteria were tested using the intestinal epithelial cell lines Caco-2, T84, and HT29. Two strains were selected for further assessment of their anti-inflammatory capacity in two murine models of colitis. In vivo results confirmed the high anti-inflammatory capacity of a Bifidobacterium bifidum strain.

Repurposing auranofin as a Clostridioides difficile therapeutic

2019 ◽  
Author(s):  
Melanie L Hutton ◽  
Havva Pehlivanoglu ◽  
Callum J Vidor ◽  
Meagan L James ◽  
Melanie J Thomson ◽  
...  
Keyword(s):  
Therapeutic Option ◽  
Survival Rates ◽  
Treatment Strategies ◽  
Toxin Production ◽  
Spore Production ◽  
Clostridioides Difficile ◽  
New Treatment ◽  
Gut Damage

Abstract Background Clostridioides difficile (previously Clostridium difficile) is the leading cause of nosocomial, antibiotic-associated diarrhoea worldwide. Currently, the gold standard of treatment for C. difficile infection (CDI) is vancomycin or metronidazole, although these antibiotics also perturb the protective resident microbiota, often resulting in disease relapse. Thus, an urgent need remains for the development of new treatment strategies. Auranofin is an FDA-approved oral antirheumatic drug that was previously shown to inhibit C. difficile vegetative cell growth, toxin production and spore production in vitro. Objectives To determine the efficacy of auranofin as a CDI therapeutic by examining the effect of treatment on toxin and spore production in vitro and in vivo, and on disease outcomes in mice. Methods C. difficile cultures were treated with auranofin and examined for effects on sporulation and toxin production by sporulation assay and ELISA, respectively. Mice were pretreated with auranofin prior to infection with C. difficile and monitored for physiological conditions, survival and gut damage compared with control animals. Faeces from mice were analysed to determine whether auranofin reduces sporulation and toxin production in vivo. Results Auranofin significantly reduces sporulation and toxin production under in vitro conditions and in infected mice in vivo. Mice treated with auranofin lost less weight, displayed a significant increase in survival rates and had significantly less toxin-mediated damage in their colon and caecum compared with control mice. Conclusions Auranofin shows promise as a prospective therapeutic option for C. difficile infections.

Transplantation of Adipose-derived Cells for Periodontal Regeneration: A Systematic Review

2019 ◽  
Vol 14 (6) ◽  
pp. 504-518 ◽  
Author(s):  
Dilcele Silva Moreira Dziedzic ◽  
Bassam Felipe Mogharbel ◽  
Priscila Elias Ferreira ◽  
Ana Carolina Irioda ◽  
Katherine Athayde Teixeira de Carvalho
Keyword(s):  
Systematic Review ◽  
Animal Models ◽  
Platelet Rich Plasma ◽  
Periodontal Regeneration ◽  
In Vitro Studies ◽  
In Vivo Studies ◽  
Cell Sources ◽  
Study Designs

This systematic review evaluated the transplantation of cells derived from adipose tissue for applications in dentistry. SCOPUS, PUBMED and LILACS databases were searched for in vitro studies and pre-clinical animal model studies using the keywords “ADIPOSE”, “CELLS”, and “PERIODONTAL”, with the Boolean operator “AND”. A total of 160 titles and abstracts were identified, and 29 publications met the inclusion criteria, 14 in vitro and 15 in vivo studies. In vitro studies demonstrated that adipose- derived cells stimulate neovascularization, have osteogenic and odontogenic potential; besides adhesion, proliferation and differentiation on probable cell carriers. Preclinical studies described improvement of bone and periodontal healing with the association of adipose-derived cells and the carrier materials tested: Platelet Rich Plasma, Fibrin, Collagen and Synthetic polymer. There is evidence from the current in vitro and in vivo data indicating that adipose-derived cells may contribute to bone and periodontal regeneration. The small quantity of studies and the large variation on study designs, from animal models, cell sources and defect morphology, did not favor a meta-analysis. Additional studies need to be conducted to investigate the regeneration variability and the mechanisms of cell participation in the processes. An overview of animal models, cell sources, and scaffolds, as well as new perspectives are provided for future bone and periodontal regeneration study designs.

scholarly journals Heme Oxygenase-1 Deficiency and Oxidative Stress: A Review of 9 Independent Human Cases and Animal Models

2021 ◽  
Vol 22 (4) ◽  
pp. 1514 ◽  
Author(s):  
Akihiro Yachie
Keyword(s):  
Oxidative Stress ◽  
Animal Models ◽  
Heme Oxygenase ◽  
Inflammatory Diseases ◽  
Cell Types ◽  
Pharmacological Intervention ◽  
Heme Oxygenase 1 ◽  
Inflammatory Reactions

Since Yachie et al. reported the first description of human heme oxygenase (HO)-1 deficiency more than 20 years ago, few additional human cases have been reported in the literature. A detailed analysis of the first human case of HO-1 deficiency revealed that HO-1 is involved in the protection of multiple tissues and organs from oxidative stress and excessive inflammatory reactions, through the release of multiple molecules with anti-oxidative stress and anti-inflammatory functions. HO-1 production is induced in vivo within selected cell types, including renal tubular epithelium, hepatic Kupffer cells, vascular endothelium, and monocytes/macrophages, suggesting that HO-1 plays critical roles in these cells. In vivo and in vitro studies have indicated that impaired HO-1 production results in progressive monocyte dysfunction, unregulated macrophage activation and endothelial cell dysfunction, leading to catastrophic systemic inflammatory response syndrome. Data from reported human cases of HO-1 deficiency and numerous studies using animal models suggest that HO-1 plays critical roles in various clinical settings involving excessive oxidative stress and inflammation. In this regard, therapy to induce HO-1 production by pharmacological intervention represents a promising novel strategy to control inflammatory diseases.

scholarly journals Preclinical characterization of dostarlimab, a therapeutic anti-PD-1 antibody with potent activity to enhance immune function in in vitro cellular assays and in vivo animal models

mAbs ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 1954136
Author(s):  
Sujatha Kumar ◽  
Srimoyee Ghosh ◽  
Geeta Sharma ◽  
Zebin Wang ◽  
Marilyn R. Kehry ◽  
...  
Keyword(s):  
Animal Models ◽  
Immune Function ◽  
Cellular Assays ◽  
In Vivo Animal Models
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