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Ramos CP, Siqueira WF, Viana LA, Cunha JLR, Fujiwara RT, Amarante VS, Souza TGV, Silva ROS. Development of two recombinant vaccines against Clostridioides difficile infection and immunogenicity in pregnant sows and neonatal piglets. Anaerobe 2024; 89:102896. [PMID: 39127403 DOI: 10.1016/j.anaerobe.2024.102896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 06/11/2024] [Accepted: 08/06/2024] [Indexed: 08/12/2024]
Abstract
INTRODUCTION Clostridioides difficile is the main cause of antibiotic-associated diarrhea in humans and is a major enteropathogen in several animal species. In newborn piglets, colonic lesions caused by C. difficile A and B toxins (TcdA and TcdB, respectively) cause diarrhea and significant production losses. OBJECTIVE The present study aimed to develop two recombinant vaccines from immunogenic C-terminal fragments of TcdA and TcdB and evaluate the immune response in rabbits and in breeding sows. Two vaccines were produced: bivalent (rAB), consisting of recombinant fragments of TcdA and TcdB, and chimeric (rQAB), corresponding to the synthesis of the same fragments in a single protein. Groups of rabbits were inoculated with 10 or 50 μg of proteins adjuvanted with aluminum or 0.85 % sterile saline in a final volume of 1 mL/dose. Anti-TcdA and anti-TcdB IgG antibodies were detected in rabbits and sows immunized with both rAB and rQAB vaccines by ELISA. The vaccinated sows were inoculated intramuscularly with 20 μg/dose using a prime-boost approach. RESULTS Different antibody titers (p ≤ 0.05) were observed among the vaccinated groups of sows (rAB and rQAB) and control. Additionally, newborn piglets from vaccinated sows were also positive for anti-TcdA and anti-TcdB IgGs, in contrast to control piglets (p ≤ 0.05). Immunization of sows with the rQAB vaccine conferred higher anti-TcdA and anti-TcdB responses in piglets, suggesting the superiority of this compound over rAB. CONCLUSION The synthesized recombinant proteins were capable of inducing antibody titers against C. difficile toxins A and B in sows, and were passively transferred to piglets through colostrum.
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Affiliation(s)
- Carolina P Ramos
- Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Williane F Siqueira
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Laila A Viana
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - João L R Cunha
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | - Ricardo T Fujiwara
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Victor S Amarante
- Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Thayanne G V Souza
- Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Rodrigo O S Silva
- Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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Norman KM, Lang GA, Shadid TM, Honold ST, Reel JM, Cox MA, Ballard JD, Lang ML. Clostridioides difficile toxin B subverts germinal center and antibody recall responses by stimulating a drug-treatable CXCR4-dependent mechanism. Cell Rep 2024; 43:114245. [PMID: 38761377 PMCID: PMC11210377 DOI: 10.1016/j.celrep.2024.114245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 04/04/2024] [Accepted: 05/02/2024] [Indexed: 05/20/2024] Open
Abstract
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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Affiliation(s)
- Kaylee M Norman
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Gillian A Lang
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Tyler M Shadid
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Sydney T Honold
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Jessica M Reel
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Maureen A Cox
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Jimmy D Ballard
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA
| | - Mark L Lang
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences, Oklahoma City, OK 73104, USA.
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3
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Tornel W, Sharma I, Osmani H, Moonah S. Prosurvival Pathway Protects From Clostridioides difficile Toxin-Mediated Cell Death. J Infect Dis 2024; 229:1519-1522. [PMID: 37972231 PMCID: PMC11095527 DOI: 10.1093/infdis/jiad481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 08/31/2023] [Accepted: 10/26/2023] [Indexed: 11/19/2023] Open
Abstract
There is an urgent need for new nonantibiotic-based treatment strategies for Clostridioides difficile infection. C. difficile toxin B (TcdB) is a virulent factor that is essential for causing disease. Here, we investigated whether a survival-signaling pathway could protect against TcdB. We found significant increase in caspase-3 apoptotic activity in intestinal epithelial cells of mice exposed to TcdB. Subsequently, activation of the MIF-CD74-Akt prosurvival signaling pathway blocked TcdB-induced caspase-3 activity and intestinal epithelial cell death. This brief report provides proof-of-concept that targeting prosurvival pathways may represent a unique antibiotic-independent strategy for protecting against C. difficile toxin-mediated cell death.
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Affiliation(s)
- William Tornel
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Ishrya Sharma
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Hiba Osmani
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Shannon Moonah
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia Health System, Charlottesville, Virginia, USA
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Karnchanapandh K, Hanpaibool C, Sanachai K, Rungrotmongkol T. Elucidation of bezlotoxumab binding specificity to toxin B in Clostridioides difficile. J Biomol Struct Dyn 2024; 42:1617-1628. [PMID: 37098802 DOI: 10.1080/07391102.2023.2201360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 04/05/2023] [Indexed: 04/27/2023]
Abstract
C. difficile or Clostridioides difficile infection (CDI) is currently one of the major causes of epidemics worldwide. Toxin B from Clostridioides difficile toxin B (TcdB) infection is the main target protein inhibiting CDI recurrence. Clinical research suggested that bezlotoxumab's (Bez) efficiency is significantly reduced in neutralizing the B2 strain compared to the B1 strain. The monoclonal antibody (mAb) functions by binding to the epitope 1 and 2 regions in the combined repetitive oligopeptide (CROP) domain. Some binding residues are distinctively different between B1 and B2 strains. In this work, we aimed to elucidate and compare insights into the interaction of toxins B1 and B2 in complex with Bez by using all-atom molecular dynamics (MD) simulations and binding free energy calculations. The predicted ΔGbinding values suggested that the antibody (Ab) could bind to toxin B1 significantly better than B2, supported by higher salt bridge and hydrogen bonding (H-bonding) interactions, as well as the number of contact residues between the two focused proteins. The toxin B1 residues important for binding with Bez were E1878, T1901, E1902, F1905, N1941, V1946, N2031, T2032, E2033, V2076, V2077, and E2092. The lower susceptibility of Bez towards toxin B2 was primarily due to a change of residue E2033 from glutamate to alanine (A2033) and the loss of E1878 and E1902 contributions, as determined by the intermolecular interaction changes from the dynamic residue interaction network (dRIN) analysis. The obtained data strengthen our understanding of Bez/toxin B binding.
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Affiliation(s)
- Kun Karnchanapandh
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok, Thailand
| | - Chonnikan Hanpaibool
- Center of Excellence in Biocatalyst and Sustainable Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Kamonpan Sanachai
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Thanyada Rungrotmongkol
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok, Thailand
- Center of Excellence in Biocatalyst and Sustainable Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
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Liu J, Zhu W, Lessing DJ, Chu W. Synthetic microbial consortia for the treatment of Clostridioides difficile infection in mice model. Microb Biotechnol 2023; 16:1985-2006. [PMID: 37602713 PMCID: PMC10527189 DOI: 10.1111/1751-7915.14333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/01/2023] [Accepted: 08/08/2023] [Indexed: 08/22/2023] Open
Abstract
Clostridioides difficile infection (CDI) as of recent has become a great concern to the impact on human health due to its high hazardous risk and rate of recurrence. Live bacterial therapeutics is a promising method to treat or prevent CDI. Here, a synthetic microbial consortia (SMC) B10 was constructed using probiotic strains with antibacterial and anti-quorum sensing activities, and the therapeutic effect of SMC B10 against C. difficile infection was evaluated in vitro. Compared to the model group, the treatment of SMC B10 significantly increased the survival rate. The clinical signs of mice were significantly ameliorated, especially the cecum injury, while the secretion of pro-inflammatory associated cytokines such as IL-1α, IL-6, IL-17A and TNF-α was reduced, the expression of TLR4 was inhibited, which alleviated the inflammatory response, and the expression of the tight junction protein Claudin-1 was increased, ultimately promoting the recovery of host health. The treatment of B10 restored gut microbiota dysbiosis and led to a healthy intestinal microbiota structure, significantly improved alpha diversity, suppressing potentially harmful bacteria and restoring other core bacterial species. In conclusion, SMC B10 can effectively treat CDI through modulate gut microbiota and attenuate the inflammatory response.
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Affiliation(s)
- Jinqiu Liu
- Department of Pharmaceutical Microbiology, School of Life Science and TechnologyChina Pharmaceutical UniversityNanjingChina
| | - Wei Zhu
- Department of Pharmaceutical Microbiology, School of Life Science and TechnologyChina Pharmaceutical UniversityNanjingChina
| | - Duncan James Lessing
- Department of Pharmaceutical Microbiology, School of Life Science and TechnologyChina Pharmaceutical UniversityNanjingChina
| | - Weihua Chu
- Department of Pharmaceutical Microbiology, School of Life Science and TechnologyChina Pharmaceutical UniversityNanjingChina
- State Key Laboratory of Natural MedicinesChina Pharmaceutical UniversityNanjingChina
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Dicks LMT. Biofilm Formation of Clostridioides difficile, Toxin Production and Alternatives to Conventional Antibiotics in the Treatment of CDI. Microorganisms 2023; 11:2161. [PMID: 37764005 PMCID: PMC10534356 DOI: 10.3390/microorganisms11092161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/16/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023] Open
Abstract
Clostridioides difficile is considered a nosocomial pathogen that flares up in patients exposed to antibiotic treatment. However, four out of ten patients diagnosed with C. difficile infection (CDI) acquired the infection from non-hospitalized individuals, many of whom have not been treated with antibiotics. Treatment of recurrent CDI (rCDI) with antibiotics, especially vancomycin (VAN) and metronidazole (MNZ), increases the risk of experiencing a relapse by as much as 70%. Fidaxomicin, on the other hand, proved more effective than VAN and MNZ by preventing the initial transcription of RNA toxin genes. Alternative forms of treatment include quorum quenching (QQ) that blocks toxin synthesis, binding of small anion molecules such as tolevamer to toxins, monoclonal antibodies, such as bezlotoxumab and actoxumab, bacteriophage therapy, probiotics, and fecal microbial transplants (FMTs). This review summarizes factors that affect the colonization of C. difficile and the pathogenicity of toxins TcdA and TcdB. The different approaches experimented with in the destruction of C. difficile and treatment of CDI are evaluated.
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Affiliation(s)
- Leon M T Dicks
- Department of Microbiology, Stellenbosch University, Stellenbosch 7600, South Africa
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Murphy CK, O’Donnell MM, Hegarty JW, Schulz S, Hill C, Ross RP, Rea MC, Farquhar R, Chesnel L. Novel, non-colonizing, single-strain live biotherapeutic product ADS024 protects against Clostridioides difficile infection challenge in vivo. World J Gastrointest Pathophysiol 2023; 14:71-85. [PMID: 37727283 PMCID: PMC10505952 DOI: 10.4291/wjgp.v14.i4.71] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/02/2023] [Accepted: 08/07/2023] [Indexed: 08/24/2023] Open
Abstract
BACKGROUND The Centers for Disease Control and Prevention estimate that Clostridioides difficile (C. difficile) causes half a million infections (CDI) annually and is a major cause of total infectious disease death in the United States, causing inflammation of the colon and potentially deadly diarrhea. We recently reported the isolation of ADS024, a Bacillus velezensis (B. velezensis) strain, which demonstrated direct in vitro bactericidal activity against C. difficile, with minimal collateral impact on other members of the gut microbiota. In this study, we hypothesized that in vitro activities of ADS024 will translate in vivo to protect against CDI challenge in mouse models. AIM To investigate the in vivo efficacy of B. velezensis ADS024 in protecting against CDI challenge in mouse models. METHODS To mimic disruption of the gut microbiota, the mice were exposed to vancomycin prior to dosing with ADS024. For the mouse single-dose study, the recovery of ADS024 was assessed via microbiological analysis of intestinal and fecal samples at 4 h, 8 h, and 24 h after a single oral dose of 5 × 108 colony-forming units (CFU)/mouse of freshly grown ADS024. The single-dose study in miniature swine included groups that had been pre-dosed with vancomycin and that had been exposed to a dose range of ADS024, and a group that was not pre-dosed with vancomycin and received a single dose of ADS024. The ADS024 colonies [assessed by quantitative polymerase chain reaction (qPCR) using ADS024-specific primers] were counted on agar plates. For the 28-d miniature swine study, qPCR was used to measure ADS024 levels from fecal samples after oral administration of ADS024 capsules containing 5 × 109 CFU for 28 consecutive days, followed by MiSeq compositional sequencing and bioinformatic analyses to measure the impact of ADS024 on microbiota. Two studies were performed to determine the efficacy of ADS024 in a mouse model of CDI: Study 1 to determine the effects of fresh ADS024 culture and ADS024 spore preparations on the clinical manifestations of CDI in mice, and Study 2 to compare the efficacy of single daily doses vs dosing 3 times per day with fresh ADS024. C. difficile challenge was performed 24 h after the start of ADS024 exposure. To model the human distal colon, an anerobic fecal fermentation system was used. MiSeq compositional sequencing and bioinformatic analyses were performed to measure microbiota diversity changes following ADS024 treatment. To assess the potential of ADS024 to be a source of antibiotic resistance, its susceptibility to 18 different antibiotics was tested. RESULTS In a mouse model of CDI challenge, single daily doses of ADS024 were as efficacious as multiple daily doses in protecting against subsequent challenge by C. difficile pathogen-induced disease. ADS024 showed no evidence of colonization based on the observation that the ADS024 colonies were not recovered 24 h after single doses in mice or 72 h after single doses in miniature swine. In a 28-d repeat-dose study in miniature swine, ADS024 was not detected in fecal samples using plating and qPCR methods. Phylogenetic analysis performed in the human distal colon model showed that ADS024 had a selective impact on the healthy human colonic microbiota, similarly to the in vivo studies performed in miniature swine. Safety assessments indicated that ADS024 was susceptible to all the antibiotics tested, while in silico testing revealed a low potential for off-target activity or virulence and antibiotic-resistance mechanisms. CONCLUSION Our findings, demonstrating in vivo efficacy of ADS024 in protecting against CDI challenge in mouse models, support the use of ADS024 in preventing recurrent CDI following standard antibiotic treatment.
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Affiliation(s)
- Christopher K Murphy
- Research and Development, Adiso Therapeutics Inc., Concord, MA 01742, United States
| | | | - James W Hegarty
- Teagasc Food Research Centre, Moorepark Fermoy, Cork P61 C996, Ireland
| | - Sarah Schulz
- APC Microbiome Ireland, University College Cork, Cork T12 K8AF, Ireland
| | - Colin Hill
- APC Microbiome Ireland, University College Cork, Cork T12 K8AF, Ireland
| | - R Paul Ross
- APC Microbiome Ireland, University College Cork, Cork T12 K8AF, Ireland
| | - Mary C Rea
- Teagasc Food Research Centre, Moorepark Fermoy, Cork P61 C996, Ireland
| | - Ronald Farquhar
- Executive Leadership Team, Adiso Therapeutics Inc., Concord, MA 01742, United States
| | - Laurent Chesnel
- Research and Development, Adiso Therapeutics Inc., Concord, MA 01742, United States
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Grześkowiak Ł, Saliu EM, Wessels AG, Martínez-Vallespín B, Männer K, Cerón JJ, Vahjen W, Zentek J. Clostridioides difficile-mesocolonic oedema in neonatal suckling piglets develops regardless of the fibre composition in sow's diets. Animal 2023; 17:100697. [PMID: 36621110 DOI: 10.1016/j.animal.2022.100697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 12/06/2022] [Accepted: 12/06/2022] [Indexed: 12/15/2022] Open
Abstract
Maternal dietary factors have been reported to influence Clostridioides difficile colonisation in the offspring. Twenty suckling piglets from sows fed diets supplemented with high-fermentable sugar beet pulp (SBP) or low-fermentable lignocellulose (LNC) fibres during gestation and lactation were dissected in the first week after birth. Postmortem analysis included clinical mesocolon and faecal scoring, concentration of C. difficile and respective toxins in colon digesta and faeces, immunoglobulins in serum and inflammatory markers in serum and colon tissues. Sow colostrum was assessed for nutrients, immunoglobulins and biogenic amines. Toxin-neutralising IgG antibodies were measured in colostrum and serum of the sows, and in colon digesta and serum of the piglets. Mesocolonic oedema of different severity was present in most of the piglets from both sows' feeding groups. Concentrations of C. difficile, toxins and calprotectin in colon digesta and faecal contents did not differ between the study piglets. Calprotectin correlated positively with mesocolon score (rho = 413, P = 0.07). Piglets from sows fed LNC vs SBP tended to have higher IgA (P = 0.089), IgG (P = 0.053), total Ig (P = 0.053), albumin (P = 0.075) and total protein content (P = 0.007) in serum. Colon tissues of piglets from the SFB vs LNC had upregulated expression of ZO-1 (P = 0.021), PCNA (P = 0.015) and TGF-β (P = 0.014). Titers of anti-toxin-IgG-antibodies in serum and colostrum and in piglet colon digesta and serum did not differ between sows from both dietary groups, but they all showed strong positive correlations. In conclusion, dietary sugar beet pulp or lignocellulose fed to sows did not influence the concentrations of C. difficile and toxins titers in colon digesta and faeces of neonatal piglets.
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Affiliation(s)
- Łukasz Grześkowiak
- Institute of Animal Nutrition, Freie Universität Berlin, Berlin 14195 Germany.
| | - Eva-Maria Saliu
- Institute of Animal Nutrition, Freie Universität Berlin, Berlin 14195 Germany
| | - Anna Grete Wessels
- Institute of Animal Nutrition, Freie Universität Berlin, Berlin 14195 Germany
| | | | - Klaus Männer
- Institute of Animal Nutrition, Freie Universität Berlin, Berlin 14195 Germany
| | - José Joaquín Cerón
- Interdisciplinary Laboratory of Clinical Pathology, Interlab-UMU, University of Murcia, 30100 Murcia, Spain
| | - Wilfried Vahjen
- Institute of Animal Nutrition, Freie Universität Berlin, Berlin 14195 Germany
| | - Jürgen Zentek
- Institute of Animal Nutrition, Freie Universität Berlin, Berlin 14195 Germany
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Make It Less difficile: Understanding Genetic Evolution and Global Spread of Clostridioides difficile. Genes (Basel) 2022; 13:genes13122200. [PMID: 36553467 PMCID: PMC9778335 DOI: 10.3390/genes13122200] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/14/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022] Open
Abstract
Clostridioides difficile is an obligate anaerobic pathogen among the most common causes of healthcare-associated infections. It poses a global threat due to the clinical outcomes of infection and resistance to antibiotics recommended by international guidelines for its eradication. In particular, C. difficile infection can lead to fulminant colitis associated with shock, hypotension, megacolon, and, in severe cases, death. It is therefore of the utmost urgency to fully characterize this pathogen and better understand its spread, in order to reduce infection rates and improve therapy success. This review aims to provide a state-of-the-art overview of the genetic variation of C. difficile, with particular regard to pathogenic genes and the correlation with clinical issues of its infection. We also summarize the current typing techniques and, based on them, the global distribution of the most common ribotypes. Finally, we discuss genomic surveillance actions and new genetic engineering strategies as future perspectives to make it less difficile.
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Mileto SJ, Hutton ML, Walton SL, Das A, Ioannidis LJ, Ketagoda D, Quinn KM, Denton KM, Hansen DS, Lyras D. Bezlotoxumab prevents extraintestinal organ damage induced by Clostridioides difficile infection. Gut Microbes 2022; 14:2117504. [PMID: 36045589 PMCID: PMC9450906 DOI: 10.1080/19490976.2022.2117504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Clostridioides difficile is the most common cause of infectious antibiotic-associated diarrhea, with disease mediated by two major toxins TcdA and TcdB. In severe cases, systemic disease complications may arise, resulting in fatal disease. Systemic disease in animal models has been described, with thymic damage an observable consequence of severe disease in mice. Using a mouse model of C. difficile infection, we examined this disease phenotype, focussing on the thymus and serum markers of systemic disease. The efficacy of bezlotoxumab, a monoclonal TcdB therapeutic, to prevent toxin mediated systemic disease complications was also examined. C. difficile infection causes toxin-dependent thymic damage and CD4+CD8+ thymocyte depletion in mice. These systemic complications coincide with changes in biochemical markers of liver and kidney function, including increased serum urea and creatinine, and hypoglycemia. Administration of bezlotoxumab during C. difficile infection prevents systemic disease and thymic atrophy, without blocking gut damage, suggesting the leakage of gut contents into circulation may influence systemic disease. As the thymus has such a crucial role in T cell production and immune system development, these findings may have important implications in relapse of C. difficile disease and impaired immunity during C. difficile infection. The prevention of thymic atrophy and reduced systemic response following bezlotoxumab treatment, without altering colonic damage, highlights the importance of systemic disease in C. difficile infection, and provides new insights into the mechanism of action for this therapeutic.Abbreviations: Acute kidney injury (AKI); Alanine Transaminase (ALT); Aspartate Aminotransferase (AST); C. difficile infection (CDI); chronic kidney disease (CKD); combined repetitive oligo-peptides (CROPS); cardiovascular disease (CVD); Double positive (DP); hematoxylin and eosin (H&E); immunohistochemical (IHC); multiple organ dysfunction syndrome (MODS); phosphate buffered saline (PBS); standard error of the mean (SEM); surface layer proteins (SLP); Single positive (SP); wild-type (WT).
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Affiliation(s)
- Steven J. Mileto
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
| | - Melanie L. Hutton
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
| | - Sarah L. Walton
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| | - Antariksh Das
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
| | - Lisa J. Ioannidis
- Walter and Eliza Hall Insitiute, Infectious Diseases and Immune Defence Division, Parkville, Australia,Department of Medical Biology, the University of Melbourne, Parkville, Australia
| | - Don Ketagoda
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
| | - Kylie M. Quinn
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia,RMIT University School of Biomedical and Health Sciences, Chronic Inflammatory and Infectious Diseases Program, Bundoora, Australia
| | - Kate M. Denton
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| | - Diana S. Hansen
- Walter and Eliza Hall Insitiute, Infectious Diseases and Immune Defence Division, Parkville, Australia,Department of Medical Biology, the University of Melbourne, Parkville, Australia
| | - Dena Lyras
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia,CONTACT Dena Lyras Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria3800, Australia
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Gu W, Li W, Jia S, Zhou Y, Yin J, Wu Y, Fu X. Antibiotic resistance and genomic features of Clostridioides difficile in southwest China. PeerJ 2022; 10:e14016. [PMID: 36093337 PMCID: PMC9454788 DOI: 10.7717/peerj.14016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/15/2022] [Indexed: 01/19/2023] Open
Abstract
Background Clostridioides difficile infection (CDI) caused by toxigenic strains leads to antibiotic-related diarrhea, colitis, or even fatal pseudomembranous enteritis. Previously, we conducted a cross-sectional study on prevalence of CDI in southwest China. However, the antibiotics resistance and characteristics of genomes of these isolates are still unknown. Methods Antibiotic susceptibility testing with E-test strips and whole genome sequence analysis were used to characterize the features of these C. difficile isolates. Results Forty-nine strains of C. difficile were used in this study. Five isolates were non-toxigenic and the rest carried toxigenic genes. We have previously reported that ST35/RT046, ST3/RT001 and ST3/RT009 were the mostly distributed genotypes of strains in the children group. In this study, all the C. difficile isolates were sensitive to metronidazole, meropenem, amoxicillin/clavulanic acid and vancomycin. Most of the strains were resistant to erythromycin, gentamicin and clindamycin. The annotated resistant genes, such as macB, vanRA, vanRG, vanRM, arlR, and efrB were mostly identified related to macrolide, glycopeptide, and fluoroquinolone resistance. Interestingly, 77.55% of the strains were considered as multi-drug resistant (MDR). Phylogenetic analysis based on core genome of bacteria revealed all the strains were divided into clade 1 and clade 4. The characteristics of genome diversity for clade 1 could be found. None of the isolates showed 18-bp deletion of tcdC as RT027 strain as described before, and polymorphism of tcdB showed a high degree of conservation than tcdA gene. Conclusions Most of the C. difficile isolates in this study were resistant to macrolide and aminoglycoside antibiotics. Moreover, the MDR strains were commonly found. All the isolates belonged to clade 1 and clade 4 according to phylogenetic analysis of bacterial genome, and highly genomic diversity of clade 1 was identified for these strains.
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Affiliation(s)
- Wenpeng Gu
- Department of Acute Infectious Diseases Control and Prevention, Yunnan Provincial Centre for Disease Control and Prevention, Kunming, China
| | - Wenge Li
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Senquan Jia
- Department of Acute Infectious Diseases Control and Prevention, Yunnan Provincial Centre for Disease Control and Prevention, Kunming, China
| | - Yongming Zhou
- Department of Acute Infectious Diseases Control and Prevention, Yunnan Provincial Centre for Disease Control and Prevention, Kunming, China
| | - Jianwen Yin
- Department of Acute Infectious Diseases Control and Prevention, Yunnan Provincial Centre for Disease Control and Prevention, Kunming, China
| | - Yuan Wu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Beijing, China
| | - Xiaoqing Fu
- Department of Acute Infectious Diseases Control and Prevention, Yunnan Provincial Centre for Disease Control and Prevention, Kunming, China
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12
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Raeisi H, Azimirad M, Nabavi-Rad A, Asadzadeh Aghdaei H, Yadegar A, Zali MR. Application of recombinant antibodies for treatment of Clostridioides difficile infection: Current status and future perspective. Front Immunol 2022; 13:972930. [PMID: 36081500 PMCID: PMC9445313 DOI: 10.3389/fimmu.2022.972930] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 08/03/2022] [Indexed: 11/13/2022] Open
Abstract
Clostridioides difficile (C. difficile), known as the major cause of antibiotic-associated diarrhea, is regarded as one of the most common healthcare-associated bacterial infections worldwide. Due to the emergence of hypervirulent strains, development of new therapeutic methods for C. difficile infection (CDI) has become crucially important. In this context, antibodies have been introduced as valuable tools in the research and clinical environments, as far as the effectiveness of antibody therapy for CDI was reported in several clinical investigations. Hence, production of high-performance antibodies for treatment of CDI would be precious. Traditional approaches of antibody generation are based on hybridoma technology. Today, application of in vitro technologies for generating recombinant antibodies, like phage display, is considered as an appropriate alternative to hybridoma technology. These techniques can circumvent the limitations of the immune system and they can be exploited for production of antibodies against different types of biomolecules in particular active toxins. Additionally, DNA encoding antibodies is directly accessible in in vitro technologies, which enables the application of antibody engineering in order to increase their sensitivity and specificity. Here, we review the application of antibodies for CDI treatment with an emphasis on recombinant fragment antibodies. Also, this review highlights the current and future prospects of the aforementioned approaches for antibody-mediated therapy of CDI.
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Affiliation(s)
- Hamideh Raeisi
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Masoumeh Azimirad
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Nabavi-Rad
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hamid Asadzadeh Aghdaei
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Yadegar
- Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- *Correspondence: Abbas Yadegar, ;
| | - Mohammad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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13
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Kunishima H, Ohge H, Suzuki H, Nakamura A, Matsumoto K, Mikamo H, Mori N, Morinaga Y, Yanagihara K, Yamagishi Y, Yoshizawa S. Japanese Clinical Practice Guidelines for Management of Clostridioides (Clostridium) difficile infection. J Infect Chemother 2022; 28:1045-1083. [PMID: 35618618 DOI: 10.1016/j.jiac.2021.12.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/16/2021] [Accepted: 12/13/2021] [Indexed: 12/19/2022]
Affiliation(s)
- Hiroyuki Kunishima
- Department of Infectious Diseases, St. Marianna University School of Medicine, Japan.
| | - Hiroki Ohge
- Department of Infectious Diseases, Hiroshima University Hospital, Japan
| | - Hiromichi Suzuki
- Division of Infectious Diseases, Department of Medicine, Tsukuba Medical Center Hospital, Japan
| | - Atsushi Nakamura
- Division of Infection Control and Prevention, Nagoya City University Hospital, Japan
| | - Kazuaki Matsumoto
- Division of Pharmacodynamics, Faculty of Pharmacy, Keio University, Japan
| | - Hiroshige Mikamo
- Clinical Infectious Diseases, Graduate School of Medicine, Aichi Medical University, Japan
| | - Nobuaki Mori
- Division of General Internal Medicine and Infectious Diseases, National Hospital Organization Tokyo Medical Center, Japan
| | - Yoshitomo Morinaga
- Department of Microbiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan
| | - Katsunori Yanagihara
- Department of Laboratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Japan
| | - Yuka Yamagishi
- Clinical Infectious Diseases, Graduate School of Medicine, Aichi Medical University, Japan
| | - Sadako Yoshizawa
- Department of Clinical Laboratory/Department of Microbiology and Infectious Diseases, Toho University School of Medicine, Japan
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14
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Lang GA, Norman K, Amadou Amani S, Shadid TM, Ballard JD, Lang ML. Use of a Clostridioides difficile Murine Immunization and Challenge Model to Evaluate Single and Combination Vaccine Adjuvants Consisting of Alum and NKT Cell-Activating Ligands. Front Immunol 2022; 12:818734. [PMID: 35095921 PMCID: PMC8794951 DOI: 10.3389/fimmu.2021.818734] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/27/2021] [Indexed: 01/14/2023] Open
Abstract
Adjuvant combinations may enhance or broaden the expression of immune responses to vaccine antigens. Information on whether established Alum type adjuvants can be combined with experimental CD1d ligand adjuvants is currently lacking. In this study, we used a murine Clostridioides difficile immunization and challenge model to evaluate Alum (Alhydrogel™), α-galactosylceramide (α-GC), and one of its analogs 7DW8-5 singly and in combination as vaccine adjuvants. We observed that the Alum/α-GC combination caused modest enhancement of vaccine antigen-specific IgG1 and IgG2b responses, and a broadening to include IgG2c that did not significantly impact overall protection. Similar observations were made using the Alum/7DW8-5 combination. Examination of the impact of adjuvants on NKT cells revealed expansion of invariant NKT (iNKT) cells with modest expansion of their iNKTfh subset and little effect on diverse NKT (dNKT) cells. Side effects of the adjuvants was determined and revealed transient hepatotoxicity when Alum/α-GC was used in combination but not singly. In summary these results showed that the Alum/α-GC or the Alum/7DW8-5 combination could exert distinct effects on the NKT cell compartment and on isotype switch to produce Th1-driven IgG subclasses in addition to Alum/Th2-driven subclasses. While Alum alone was efficacious in stimulating IgG-mediated protection, and α-GC offered no apparent additional benefit in the C. difficile challenge model, the work herein reveals immune response features that could be optimized and harnessed in other vaccine contexts.
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15
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Kociolek LK, Zackular JP, Savidge T. Translational Aspects of the Immunology of Clostridioides difficile Infection: Implications for Pediatric Populations. J Pediatric Infect Dis Soc 2021; 10:S8-S15. [PMID: 34791392 PMCID: PMC8600028 DOI: 10.1093/jpids/piab089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Clostridioides difficile has become the most common healthcare-associated pathogen in the United States, leading the US Centers for Disease Control and Prevention (CDC) to classify C. difficile as an "urgent" public health threat that requires "urgent and aggressive action." This call to action has led to new discoveries that have advanced our understanding of Clostridioides difficile infection (CDI) immunology and clinical development of immunologic-based therapies for CDI prevention. However, CDI immunology research has been limited in pediatric populations, and several unanswered questions remain regarding the function of host immune response in pediatric CDI pathogenesis and the potential role of immunologic-based therapies in children. This review summarizes the innate and adaptive immune responses previously characterized in animals and humans and provides a current update on clinical development of immunologic-based therapies for CDI prevention in adults and children. These data inform the future research needs for children.
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Affiliation(s)
- Larry K Kociolek
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA,Division of Infectious Diseases, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, Illinois, USA,Corresponding Author: Larry K. Kociolek, MD, MSCI, Division of Pediatric Infectious Diseases, Ann & Robert H. Lurie Children’s Hospital of Chicago, 225 E. Chicago Ave, Box 20, Chicago, IL 60611, USA. E-mail:
| | - Joseph P Zackular
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA,Division of Protective Immunity, Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA,Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Tor Savidge
- Department of Pathology & Immunology, Baylor College of Medicine & Texas Children’s Hospital, Houston, Texas, USA
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16
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Chen K, Zhu Y, Zhang Y, Hamza T, Yu H, Saint Fleur A, Galen J, Yang Z, Feng H. A probiotic yeast-based immunotherapy against Clostridioides difficile infection. Sci Transl Med 2021; 12:12/567/eaax4905. [PMID: 33115949 DOI: 10.1126/scitranslmed.aax4905] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 02/12/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022]
Abstract
Antibiotic-resistant Clostridioides difficile is an anaerobic Gram-positive bacterium that colonizes the colon and is responsible for more than 29,000 deaths in the United States each year. Hence, C. difficile infection (CDI) poses an urgent threat to public health. Antibody-mediated neutralization of TcdA and TcdB toxins, the major virulence factors of CDI, represents an effective strategy to combat the disease without invoking antibiotic resistance. However, current antitoxin approaches are mostly based on parenteral infusion of monoclonal antibodies that are costly, narrow spectrum, and not optimized against the intestinal disease. Here, we engineered probiotic Saccharomyces boulardii to constitutively secrete a single tetra-specific antibody that potently and broadly neutralized both toxins and demonstrated protection against primary and recurrent CDI in both prophylactic and therapeutic mouse models of disease. This yeast immunotherapy is orally administered, can be used concurrently with antibiotics, and may have potential as a prophylactic against CDI risk and as a therapeutic for patients with CDI.
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Affiliation(s)
- Kevin Chen
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Yixuan Zhu
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Yongrong Zhang
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Therwa Hamza
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - Hua Yu
- FZata Inc., Halethorpe, MD 21227, USA
| | - Ashley Saint Fleur
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA
| | - James Galen
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | | | - Hanping Feng
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
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17
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AAV-mediated delivery of actoxumab and bezlotoxumab results in serum and mucosal antibody concentrations that provide protection from C. difficile toxin challenge. Gene Ther 2021; 30:455-462. [PMID: 33608675 DOI: 10.1038/s41434-021-00236-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/16/2021] [Accepted: 01/29/2021] [Indexed: 12/15/2022]
Abstract
Clostridium difficile is the leading cause of antibiotic-associated nosocomial diarrhea in the developed world. When the host-associated colon microbiome is disrupted by the ingestion of antibiotics, C. difficile spores can germinate, resulting in infection. C. difficile secretes enterotoxin A (TcdA) and cytotoxin B (TcdB) that are responsible for disease pathology. Treatment options are limited as the bacterium demonstrates resistance to many antibiotics, and even with antibacterial therapies, recurrences of C. difficile are common. Actotoxumab and bezlotoxumab are human monoclonal antibodies that bind and neutralize TcdA and TcdB, respectively. In 2016, the US food and drug administration (FDA) approved bezlotoxumab for use in the prevention of C. difficile infection recurrence. To ensure the long-term expression of antibodies, gene therapy can be used. Here, adeno-associated virus (AAV)6.2FF, a novel triple mutant of AAV6, was engineered to express either actotoxumab or bezlotoxumab in mice and hamsters. Both antibodies expressed at greater than 90 μg/mL in the serum and were detected at mucosal surfaces in both models. Hundred percent of mice given AAV6.2FF-actoxumab survived a lethal dose of TcdA. This proof of concept study demonstrates that AAV-mediated expression of C. difficile toxin antibodies is a viable approach for the prevention of recurrent C. difficile infections.
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18
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Editorial for the Special Issue: Clostridium difficile. Microorganisms 2021; 9:microorganisms9020368. [PMID: 33673344 PMCID: PMC7918445 DOI: 10.3390/microorganisms9020368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/09/2021] [Accepted: 02/12/2021] [Indexed: 11/16/2022] Open
Abstract
Clostridium difficile (reclassified as Clostridioides difficile [...].
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19
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Phylogenomics of 8,839 Clostridioides difficile genomes reveals recombination-driven evolution and diversification of toxin A and B. PLoS Pathog 2020; 16:e1009181. [PMID: 33370413 PMCID: PMC7853461 DOI: 10.1371/journal.ppat.1009181] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 02/02/2021] [Accepted: 11/23/2020] [Indexed: 12/15/2022] Open
Abstract
Clostridioides difficile is the major worldwide cause of antibiotic-associated gastrointestinal infection. A pathogenicity locus (PaLoc) encoding one or two homologous toxins, toxin A (TcdA) and toxin B (TcdB), is essential for C. difficile pathogenicity. However, toxin sequence variation poses major challenges for the development of diagnostic assays, therapeutics, and vaccines. Here, we present a comprehensive phylogenomic analysis of 8,839 C. difficile strains and their toxins including 6,492 genomes that we assembled from the NCBI short read archive. A total of 5,175 tcdA and 8,022 tcdB genes clustered into 7 (A1-A7) and 12 (B1-B12) distinct subtypes, which form the basis of a new method for toxin-based subtyping of C. difficile. We developed a haplotype coloring algorithm to visualize amino acid variation across all toxin sequences, which revealed that TcdB has diversified through extensive homologous recombination throughout its entire sequence, and formed new subtypes through distinct recombination events. In contrast, TcdA varies mainly in the number of repeats in its C-terminal repetitive region, suggesting that recombination-mediated diversification of TcdB provides a selective advantage in C. difficile evolution. The application of toxin subtyping is then validated by classifying 351 C. difficile clinical isolates from Brigham and Women's Hospital in Boston, demonstrating its clinical utility. Subtyping partitions TcdB into binary functional and antigenic groups generated by intragenic recombinations, including two distinct cell-rounding phenotypes, whether recognizing frizzled proteins as receptors, and whether it can be efficiently neutralized by monoclonal antibody bezlotoxumab, the only FDA-approved therapeutic antibody. Our analysis also identifies eight universally conserved surface patches across the TcdB structure, representing ideal targets for developing broad-spectrum therapeutics. Finally, we established an open online database (DiffBase) as a central hub for collection and classification of C. difficile toxins, which will help clinicians decide on therapeutic strategies targeting specific toxin variants, and allow researchers to monitor the ongoing evolution and diversification of C. difficile.
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20
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Principi N, Gnocchi M, Gagliardi M, Argentiero A, Neglia C, Esposito S. Prevention of Clostridium difficile Infection and Associated Diarrhea: An Unsolved Problem. Microorganisms 2020; 8:E1640. [PMID: 33114040 PMCID: PMC7690700 DOI: 10.3390/microorganisms8111640] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/18/2020] [Accepted: 10/19/2020] [Indexed: 02/08/2023] Open
Abstract
For many years, it has been known that Clostridium difficile (CD) is the primary cause of health-care-associated infectious diarrhea, afflicting approximately 1% of hospitalized patients. CD may be simply carried or lead to a mild disease, but in a relevant number of patients, it can cause a very severe, potentially fatal, disease. In this narrative review, the present possibilities of CD infection (CDI) prevention will be discussed. Interventions usually recommended for infection control and prevention can be effective in reducing CDI incidence. However, in order to overcome limitations of these measures and reduce the risk of new CDI episodes, novel strategies have been developed. As most of the cases of CDI follow antibiotic use, attempts to rationalize antibiotic prescriptions have been implemented. Moreover, to reconstitute normal gut microbiota composition and suppress CD colonization in patients given antimicrobial drugs, administration of probiotics has been suggested. Finally, active and passive immunization has been studied. Vaccines containing inactivated CD toxins or components of CD spores have been studied. Passive immunization with monoclonal antibodies against CD toxins or the administration of hyperimmune whey derived from colostrum or breast milk from immunized cows has been tried. However, most advanced methods have significant limitations as they cannot prevent colonization and development of primary CDI. Only the availability of vaccines able to face these problems can allow a resolutive approach to the total burden due to this pathogen.
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Affiliation(s)
| | - Margherita Gnocchi
- Pediatric Clinic, Pietro Barilla Children’s Hospital, University of Parma, 43126 Parma, Italy; (M.G.); (M.G.); (A.A.); (C.N.)
| | - Martina Gagliardi
- Pediatric Clinic, Pietro Barilla Children’s Hospital, University of Parma, 43126 Parma, Italy; (M.G.); (M.G.); (A.A.); (C.N.)
| | - Alberto Argentiero
- Pediatric Clinic, Pietro Barilla Children’s Hospital, University of Parma, 43126 Parma, Italy; (M.G.); (M.G.); (A.A.); (C.N.)
| | - Cosimo Neglia
- Pediatric Clinic, Pietro Barilla Children’s Hospital, University of Parma, 43126 Parma, Italy; (M.G.); (M.G.); (A.A.); (C.N.)
| | - Susanna Esposito
- Pediatric Clinic, Pietro Barilla Children’s Hospital, University of Parma, 43126 Parma, Italy; (M.G.); (M.G.); (A.A.); (C.N.)
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21
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Na’amnih W, Carmeli Y, Asato V, Goren S, Adler A, Cohen D, Muhsen K. Enhanced Humoral Immune Responses against Toxin A and B of Clostridium difficile is Associated with a Milder Disease Manifestation. J Clin Med 2020; 9:jcm9103241. [PMID: 33050453 PMCID: PMC7601293 DOI: 10.3390/jcm9103241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 09/23/2020] [Accepted: 09/30/2020] [Indexed: 01/05/2023] Open
Abstract
The role of the humoral immune response to Clostridium difficile in modulating the severity of C. difficile infection (CDI) is unclear. We compared the levels of serum immunoglobulin G (IgG) and immunoglobulin A (IgA) against toxin A (TcdA) and toxin B (TcdB) of C. difficile between CDI and control patients and according to disease severity. The levels of IgG and IgA antibodies against TcdA and TcdB were measured in sera from patients with CDI (n = 50; 19 had severe CDI) and control patients (n = 52), using ELISA. Patients with CDI had higher levels of IgG antibodies against TcdA and TcdB than controls (p = 0.001 and p = 0.04, respectively). Higher IgG levels against TcdA and TcdB were found in patients with mild vs. severe CDI 7-14 days after the diagnosis (p = 0.004 and 0.036, respectively). A factor analysis included both IgA and IgG levels against both toxins into one composite variable, which was of higher values in patients with mild vs. severe CDI (p = 0.026). In conclusion, the systemic humoral immune responses against TcdA and TcdB might modulate the severity of CDI. These preliminary findings provide a basis for future large-scale studies and support the development and evaluation of active and passive immunotherapies for CDI management.
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Affiliation(s)
- Wasef Na’amnih
- Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6139001, Israel; (V.A.); (S.G.); (A.A.); (D.C.)
- Department of Geriatric Rehabilitation, Tel-Aviv Sourasky medical Center, Tel Aviv 6423906, Israel
- Correspondence: (W.N.); (K.M.); Tel.: +972-3-6405945 (W.N.); Fax: +972-3-6409868 (W.N.)
| | - Yehuda Carmeli
- Division of Epidemiology, and the National Institute for Antibiotic Resistance and Infection Control, Tel Aviv Sourasky Medical Center, Tel Aviv 6423906, Israel;
| | - Valeria Asato
- Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6139001, Israel; (V.A.); (S.G.); (A.A.); (D.C.)
| | - Sophy Goren
- Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6139001, Israel; (V.A.); (S.G.); (A.A.); (D.C.)
| | - Amos Adler
- Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6139001, Israel; (V.A.); (S.G.); (A.A.); (D.C.)
- Clinical Microbiology Laboratory, Tel-Aviv Sourasky medical Center, Tel Aviv 6423906, Israel
| | - Dani Cohen
- Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6139001, Israel; (V.A.); (S.G.); (A.A.); (D.C.)
| | - Khitam Muhsen
- Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6139001, Israel; (V.A.); (S.G.); (A.A.); (D.C.)
- Correspondence: (W.N.); (K.M.); Tel.: +972-3-6405945 (W.N.); Fax: +972-3-6409868 (W.N.)
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22
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Danz HR, Lee S, Chapman-Bonofiglio SP, Ginese M, Beamer G, Girouard DJ, Tzipori S. The Impact of Actotoxumab Treatment of Gnotobiotic Piglets Infected With Different Clostridium difficile Isogenic Mutants. J Infect Dis 2020; 221:276-284. [PMID: 31495879 DOI: 10.1093/infdis/jiz459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/06/2019] [Indexed: 11/14/2022] Open
Abstract
Nosocomial infections with Clostridium difficile are on the rise in the Unites States, attributed to emergence of antibiotic-resistant and hypervirulent strains associated with greater likelihood of recurrent infections. In addition to antibiotics, treatment with Merck anti-toxin B (TcdB) antibody bezlotoxumab is reported to reduce recurrent infections. However, treatment with anti-toxin A (TcdA) antibody actotoxumab was associated with dramatically increased disease severity and mortality rates in humans and gnotobiotic piglets. Using isogenic mutants of C. difficile strain NAPI/BI/027 deficient in TcdA (A-B+) or TcdB (A+B-), and the wild type, we investigated how and why treatment of infected animals with anti-TcdA dramatically increased disease severity. Contrary to the hypothesis, among piglets treated with anti-TcdA, those with A+B- infection were disease free, in contrast to the disease enhancement seen in those with wild-type or A-B+ infection. It seems that the lack of TcdA, through either deletion or neutralization with anti-TcdA, reduces a competitive pressure, allowing TcdB to freely exert its profound effect, leading to increased mucosal injury and disease severity.
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Affiliation(s)
- Hillary R Danz
- Department of Infectious Diseases and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, USA
| | - Sangun Lee
- Department of Infectious Diseases and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, USA
| | - Susan P Chapman-Bonofiglio
- Department of Infectious Diseases and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, USA
| | - Melanie Ginese
- Department of Infectious Diseases and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, USA
| | - Gillian Beamer
- Department of Infectious Diseases and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, USA
| | - Donald J Girouard
- Department of Infectious Diseases and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, USA
| | - Saul Tzipori
- Department of Infectious Diseases and Global Health, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, USA
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Roberts AK, Harris HC, Smith M, Giles J, Polak O, Buckley AM, Clark E, Ewin D, Moura IB, Spitall W, Shone CC, Wilcox M, Chilton C, Donev R. A Novel, Orally Delivered Antibody Therapy and Its Potential to Prevent Clostridioides difficile Infection in Pre-clinical Models. Front Microbiol 2020; 11:578903. [PMID: 33072047 PMCID: PMC7537341 DOI: 10.3389/fmicb.2020.578903] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022] Open
Abstract
Clostridioides difficile infection (CDI) is a toxin-mediated infection in the gut and a major burden on healthcare facilities worldwide. We rationalized that it would be beneficial to design an antibody therapy that is delivered to, and is active at the site of toxin production, rather than neutralizing the circulating and luminal toxins after significant damage of the layers of the intestines has occurred. Here we describe a highly potent therapeutic, OraCAb, with high antibody titers and a formulation that protects the antibodies from digestion/inactivation in the gastrointestinal tract. The potential of OraCAb to prevent CDI in an in vivo hamster model and an in vitro human colon model was assessed. In the hamster model we optimized the ratio of the antibodies against each of the toxins produced by C. difficile (Toxins A and B). The concentration of immunoglobulins that is effective in a hamster model of CDI was determined. A highly significant difference in animal survival for those given an optimized OraCAb formulation versus an untreated control group was observed. This is the first study testing the effect of oral antibodies for treatment of CDI in an in vitro gut model seeded with a human fecal inoculum. Treatment with OraCAb successfully neutralized toxin production and did not interfere with the colonic microbiota in this model. Also, treatment with a combination of vancomycin and OraCAb prevented simulated CDI recurrence, unlike vancomycin therapy alone. These data demonstrate the efficacy of OraCAb formulation for the treatment of CDI in pre-clinical models.
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Affiliation(s)
- April K Roberts
- Toxins Group, National Infection Service, Public Health England, Porton Down, United Kingdom
| | - Hannah C Harris
- Leeds Institute of Medical Research, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Michael Smith
- Toxins Group, National Infection Service, Public Health England, Porton Down, United Kingdom
| | - Joanna Giles
- MicroPharm Ltd., Newcastle Emlyn, United Kingdom
| | | | - Anthony M Buckley
- Leeds Institute of Medical Research, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Emma Clark
- Leeds Institute of Medical Research, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Duncan Ewin
- Leeds Institute of Medical Research, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Ines B Moura
- Leeds Institute of Medical Research, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - William Spitall
- Leeds Institute of Medical Research, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Clifford C Shone
- Toxins Group, National Infection Service, Public Health England, Porton Down, United Kingdom
| | - Mark Wilcox
- Leeds Institute of Medical Research, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom.,Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds General Infirmary, Leeds, United Kingdom
| | - Caroline Chilton
- Leeds Institute of Medical Research, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Rossen Donev
- MicroPharm Ltd., Newcastle Emlyn, United Kingdom
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24
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Giacobbe DR, Dettori S, Di Bella S, Vena A, Granata G, Luzzati R, Petrosillo N, Bassetti M. Bezlotoxumab for Preventing Recurrent Clostridioides difficile Infection: A Narrative Review from Pathophysiology to Clinical Studies. Infect Dis Ther 2020; 9:481-494. [PMID: 32632582 PMCID: PMC7452994 DOI: 10.1007/s40121-020-00314-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Indexed: 12/17/2022] Open
Abstract
Clostridioides difficile infection (CDI) and recurrent CDI (rCDI) remain associated with a reduction in the patients’ quality of life and with increased healthcare costs. Bezlotoxumab is a monoclonal antibody against toxin B of C. difficile, approved for prevention of rCDI. In this narrative review, we briefly discuss the pathophysiology of CDI and the mechanism of action of bezlotoxumab, as well as the available evidence from investigational and observational studies in terms of efficacy, effectiveness, and safety of bezlotoxumab for the prevention of rCDI. Overall, bezlotoxumab has proved efficacious in reducing the burden of rCDI, thereby providing clinicians with an important novel strategy to achieve sustained cure. Nonetheless, experiences outside randomized controlled trials (RCTs) remain scant, and mostly represented by case series without a control group. Along with the conduction of RCTs to directly compare bezlotoxumab with faecal microbiota transplantation (or to precisely evaluate the role of their combined use), further widening our post-marketing experience remains paramount to firmly guide the use of bezlotoxumab outside RCTs, and to clearly identify those real-life settings where its preventive benefits can be exploited most.
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Affiliation(s)
- Daniele Roberto Giacobbe
- Infectious Diseases Unit, Ospedale Policlinico San Martino, IRCCS, Genoa, Italy.
- Department of Health Sciences, University of Genoa, Genoa, Italy.
| | - Silvia Dettori
- Infectious Diseases Unit, Ospedale Policlinico San Martino, IRCCS, Genoa, Italy
- Department of Health Sciences, University of Genoa, Genoa, Italy
| | - Stefano Di Bella
- Clinical Department of Medical, Surgical and Health Sciences, Trieste University, Trieste, Italy
| | - Antonio Vena
- Infectious Diseases Unit, Ospedale Policlinico San Martino, IRCCS, Genoa, Italy
| | - Guido Granata
- Clinical and Research Department for Infectious Diseases, Severe and Immunedepression-Associated Infections Unit, National Institute for Infectious Diseases L. Spallanzani, IRCCS, Rome, Italy
| | - Roberto Luzzati
- Clinical Department of Medical, Surgical and Health Sciences, Trieste University, Trieste, Italy
| | - Nicola Petrosillo
- Clinical and Research Department for Infectious Diseases, Severe and Immunedepression-Associated Infections Unit, National Institute for Infectious Diseases L. Spallanzani, IRCCS, Rome, Italy
| | - Matteo Bassetti
- Infectious Diseases Unit, Ospedale Policlinico San Martino, IRCCS, Genoa, Italy
- Department of Health Sciences, University of Genoa, Genoa, Italy
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25
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Farrow MA, Chumber NM, Bloch SC, King M, Moton-Melancon K, Shupe J, Washington MK, Spiller BW, Lacy DB. Small Molecule Inhibitor Screen Reveals Calcium Channel Signaling as a Mechanistic Mediator of Clostridium difficile TcdB-Induced Necrosis. ACS Chem Biol 2020; 15:1212-1221. [PMID: 31909964 DOI: 10.1021/acschembio.9b00906] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Clostridioides difficile is the leading cause of nosocomial diarrhea in the United States. The primary virulence factors are two homologous glucosyltransferase toxins, TcdA and TcdB, that inactivate host Rho-family GTPases. The glucosyltransferase activity has been linked to a "cytopathic" disruption of the actin cytoskeleton and contributes to the disruption of tight junctions and the production of pro-inflammatory cytokines. TcdB is also a potent cytotoxin that causes epithelium necrotic damage through an NADPH oxidase (NOX)-dependent mechanism. We conducted a small molecule screen to identify compounds that confer protection against TcdB-induced necrosis. We identified an enrichment of "hit compounds" with a dihydropyridine (DHP) core which led to the discovery of a key early stage calcium signal that serves as a mechanistic link between TcdB-induced NOX activation and reactive oxygen species (ROS) production. Disruption of TcdB-induced calcium signaling (with both DHP and non-DHP molecules) is sufficient to ablate ROS production and prevent subsequent necrosis in cells and in a mouse model of intoxication.
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Affiliation(s)
- Melissa A. Farrow
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, A4116A Medical Center North, 1161 21st Avenue South, Nashville, Tennessee 37232-2363, United States
| | - Nicole M. Chumber
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, A4116A Medical Center North, 1161 21st Avenue South, Nashville, Tennessee 37232-2363, United States
| | - Sarah C. Bloch
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, A4116A Medical Center North, 1161 21st Avenue South, Nashville, Tennessee 37232-2363, United States
| | - McKenzie King
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, A4116A Medical Center North, 1161 21st Avenue South, Nashville, Tennessee 37232-2363, United States
| | - Kaycei Moton-Melancon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, A4116A Medical Center North, 1161 21st Avenue South, Nashville, Tennessee 37232-2363, United States
| | - John Shupe
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, A4116A Medical Center North, 1161 21st Avenue South, Nashville, Tennessee 37232-2363, United States
| | - Mary K. Washington
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, A4116A Medical Center North, 1161 21st Avenue South, Nashville, Tennessee 37232-2363, United States
| | - Benjamin W. Spiller
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, A4116A Medical Center North, 1161 21st Avenue South, Nashville, Tennessee 37232-2363, United States
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - D. Borden Lacy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, A4116A Medical Center North, 1161 21st Avenue South, Nashville, Tennessee 37232-2363, United States
- The Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee 37212, United States
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26
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Fischer S, Ückert AK, Landenberger M, Papatheodorou P, Hoffmann-Richter C, Mittler AK, Ziener U, Hägele M, Schwan C, Müller M, Kleger A, Benz R, Popoff MR, Aktories K, Barth H. Human peptide α-defensin-1 interferes with Clostridioides difficile toxins TcdA, TcdB, and CDT. FASEB J 2020; 34:6244-6261. [PMID: 32190927 DOI: 10.1096/fj.201902816r] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/23/2019] [Accepted: 02/27/2020] [Indexed: 12/15/2022]
Abstract
The human pathogenic bacterium Clostridioides difficile produces two exotoxins TcdA and TcdB, which inactivate Rho GTPases thereby causing C. difficile-associated diseases (CDAD) including life-threatening pseudomembranous colitis. Hypervirulent strains produce additionally the binary actin ADP-ribosylating toxin CDT. These strains are hallmarked by more severe forms of CDAD and increased frequency and severity. Once in the cytosol, the toxins act as enzymes resulting in the typical clinical symptoms. Therefore, targeting and inactivation of the released toxins are of peculiar interest. Prompted by earlier findings that human α-defensin-1 neutralizes TcdB, we investigated the effects of the defensin on all three C. difficile toxins. Inhibition of TcdA, TcdB, and CDT was demonstrated by analyzing toxin-induced changes in cell morphology, substrate modification, and decrease in transepithelial electrical resistance. Application of α-defensin-1 protected cells and human intestinal organoids from the cytotoxic effects of TcdA, TcdB, CDT, and their combination which is attributed to a direct interaction between the toxins and α-defensin-1. In mice, the application of α-defensin-1 reduced the TcdA-induced damage of intestinal loops in vivo. In conclusion, human α-defensin-1 is a specific and potent inhibitor of the C. difficile toxins and a promising agent to develop novel therapeutic options against C. difficile infections.
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Affiliation(s)
- Stephan Fischer
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany
| | - Anna-Katharina Ückert
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany
| | - Marc Landenberger
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany
| | | | | | - Ann-Katrin Mittler
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany
| | - Ulrich Ziener
- Institute of Organic Chemistry III, Ulm University, Ulm, Germany
| | - Marlen Hägele
- Department of Internal Medicine I, University of Ulm Medical Center, Ulm, Germany
| | - Carsten Schwan
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - Martin Müller
- Department of Internal Medicine I, University of Ulm Medical Center, Ulm, Germany
| | - Alexander Kleger
- Department of Internal Medicine I, University of Ulm Medical Center, Ulm, Germany
| | - Roland Benz
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Michel R Popoff
- Department of Anaerobic Bacteria, Pasteur Institute, Paris, France
| | - Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Ulm, Germany
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27
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Porcine Colostrum Protects the IPEC-J2 Cells and Piglet Colon Epithelium against Clostridioides (syn. Clostridium) difficile Toxin-Induced Effects. Microorganisms 2020; 8:microorganisms8010142. [PMID: 31968636 PMCID: PMC7022787 DOI: 10.3390/microorganisms8010142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/19/2019] [Accepted: 01/13/2020] [Indexed: 12/17/2022] Open
Abstract
Clostridioides difficile toxins are one of the main causative agents for the clinical symptoms observed during C. difficile infection in piglets. Porcine milk has been shown to strengthen the epithelial barrier function in the piglet’s intestine and may have the potential to neutralise clostridial toxins. We hypothesised that porcine colostrum exerts protective effects against those toxins in the IPEC-J2 cells and in the colon epithelium of healthy piglets. The IPEC-J2 cells were treated with either the toxins or porcine colostrum or their combination. Analyses included measurement of trans-epithelial electrical resistance (TEER), cell viability using propidium iodide by flow cytometry, gene expression of tight junction (TJ) proteins and immune markers, immunofluorescence (IF) histology of the cytoskeleton and a TJ protein assessment. Colon tissue explants from one- and two-week-old suckling piglets and from five-week-old weaned piglets were treated with C. difficile toxins in Ussing chamber assays to assess the permeability to macromolecules (FITC-dextran, HRP), followed by analysis of gene expression of TJ proteins and immune markers. Toxins decreased viability and integrity of IPEC-J2 cells in a time-dependent manner. Porcine colostrum exerted a protective effect against toxins as indicated by TEER and IF in IPEC-J2 cells. Toxins tended to increase paracellular permeability to macromolecules in colon tissues of two-week-old piglets and downregulated gene expression of occludin in colon tissues of five-week-old piglets (p = 0.05). Porcine milk including colostrum, besides other maternal factors, may be one of the important determinants of early immune programming towards protection from C. difficile infections in the offspring.
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28
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Peng Z, Simeon R, Mitchell SB, Zhang J, Feng H, Chen Z. Designed Ankyrin Repeat Protein (DARPin) Neutralizers of TcdB from Clostridium difficile Ribotype 027. mSphere 2019; 4:e00596-19. [PMID: 31578248 PMCID: PMC6796971 DOI: 10.1128/msphere.00596-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 09/11/2019] [Indexed: 02/08/2023] Open
Abstract
Clostridium difficile infection (CDI) is a leading cause of hospital-acquired diarrhea. In recent decades, the emergence of the "hypervirulent" BI/NAP1/027 strains of C. difficile significantly increased the morbidity and mortality of CDI. The pathogenesis of CDI is primarily mediated by the action of two toxins, TcdA and TcdB, with TcdB being the major virulent factor in humans. In this report, we describe the engineering of a panel of designed ankyrin repeat proteins (DARPins) that potently neutralize TcdB from the BI/NAP1/027 strains (e.g., TcdBUK1). The most effective DARPin, D16, inhibits TcdBUK1 with a 50% effective concentration (EC50) of 0.5 nM, which is >66-fold lower than that of the FDA-approved anti-TcdB antibody bezlotoxumab (EC50, ∼33 nM). Competitive enzyme-linked immunosorbent assays (ELISAs) showed that D16 blocks interactions between TcdB and its receptor, chondroitin sulfate proteoglycan 4 (CSPG4). The dimeric DARPin U3D16, which pairs D16 with DARPin U3, a disrupter of the interaction of TcdB with Frizzled 1/2/7 receptor, exhibits 10-fold-to-20-fold-enhanced neutralization potency against TcdB from C. difficile strains VPI 10463 (laboratory strain) and M68 (CF/NAP9/017) but identical activity against TcdBUK1 relative to D16. Subsequent ELISAs revealed that TcdBUK1 did not significantly interact with Frizzled 1/2/7. Computation modeling revealed 4 key differences at the Frizzled 1/2/7 binding interface which are likely responsible for the significantly reduced binding affinity.IMPORTANCE We report the engineering and characterization of designed ankyrin proteins as potent neutralizers of TcdB toxin secreted by a hypervirulent ribotype 027 strain of Clostridium difficile We further show that although TcdB toxins from both ribotype 027 and VPI 10461 interact efficiently with TcdB receptors CSPG4 and Pvrl3, TcdB027 lacks significant ability to bind the only known physiologically relevant TcdB receptor, Frizzled 1/2/7.
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Affiliation(s)
- Zeyu Peng
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, USA
| | - Rudo Simeon
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, USA
| | - Samuel B Mitchell
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, USA
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Hanping Feng
- Department of Microbial Pathogenesis, University of Maryland Dental School, Baltimore, Maryland, USA
| | - Zhilei Chen
- Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, Texas, USA
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29
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Pizarro-Guajardo M, Chamorro-Veloso N, Vidal RM, Paredes-Sabja D. New insights for vaccine development against Clostridium difficile infections. Anaerobe 2019; 58:73-79. [DOI: 10.1016/j.anaerobe.2019.04.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 04/17/2019] [Accepted: 04/25/2019] [Indexed: 02/08/2023]
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30
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Developing Gut Microbiota Exerts Colonisation Resistance to Clostridium (syn. Clostridioides) difficile in Piglets. Microorganisms 2019; 7:microorganisms7080218. [PMID: 31357520 PMCID: PMC6723027 DOI: 10.3390/microorganisms7080218] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/13/2019] [Accepted: 07/15/2019] [Indexed: 12/17/2022] Open
Abstract
Clostridium (syn. Clostridioides) difficile is considered a pioneer colonizer and may cause gut infection in neonatal piglets. The aim of this study was to explore the microbiota-C. difficile associations in pigs. We used the DNA from the faeces of four sows collected during the periparturient period and from two to three of their piglets (collected weekly until nine weeks of age) for the determination of bacterial community composition (sequencing) and C. difficile concentration (qPCR). Furthermore, C. difficile-negative faeces were enriched in a growth medium, followed by qPCR to verify the presence of this bacterium. Clostridium-sensu-stricto-1 and Lactobacillus spp. predominated the gut microbiota of the sows and their offspring. C. difficile was detected at least once in the faeces of all sows during the entire sampling period, albeit at low concentrations. Suckling piglets harboured C. difficile in high concentrations (up to log10 9.29 copy number/g faeces), which gradually decreased as the piglets aged. Enrichment revealed the presence of C. difficile in previously C. difficile-negative sow and offspring faeces. In suckling piglets, the C. difficile level was negatively correlated with carbohydrate-fermenting bacteria, and it was positively associated with potential pathogens. Shannon and richness diversity indices were negatively associated with the C. difficile counts in suckling piglets. This study showed that gut microbiota seems to set conditions for colonisation resistance against C. difficile in the offspring. However, this conclusion requires further research to include host-specific factors.
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31
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Differential effects of Clostridium difficile toxins on ion secretion and cell integrity in human intestinal cells. Pediatr Res 2019; 85:1048-1054. [PMID: 30851723 DOI: 10.1038/s41390-019-0365-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 02/04/2019] [Accepted: 02/27/2019] [Indexed: 11/08/2022]
Abstract
BACKGROUND Toxin A (TcdA), toxin B (TcdB), and binary toxin (CDT) produced by Clostridium difficile (CD) are thought to play a key role in inducing diarrhea. The aim of this study was to investigate the individual and combined roles of CD toxins in inducing enterotoxic and cytotoxic effect. METHODS Ion secretion and epithelial damage were evaluated in the Ussing chambers as measure of enterotoxic or cytotoxic effect, respectively, in human-derived intestinal cells. RESULTS When added to the mucosal side of Caco-2 cells, TcdB, but not TcdA, induced ion secretion and its effects increased in the presence of TcdA. CDT also induced ion secretion when added to either the mucosal or serosal compartment. Serosal addition of TcdB induced epithelial damage consistent with its cytotoxic effect. However, mucosal addition of TcdB had similar effects, but only in the presence of TcdA. CDT induced epithelial damage when added to the serosal side of cell monolayers, and this was associated with a late onset but prolonged effect. All data were replicated using human colon biopsies. CONCLUSIONS These data indicate that CD, through the combined and direct activity of its three toxins, induces integrated and synergic enterotoxic and cytotoxic effects on the intestinal epithelium.
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32
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Mileto S, Das A, Lyras D. Enterotoxic Clostridia: Clostridioides difficile Infections. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0015-2018. [PMID: 31124432 PMCID: PMC11026080 DOI: 10.1128/microbiolspec.gpp3-0015-2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Indexed: 12/17/2022] Open
Abstract
Clostridioides difficile is a Gram-positive, anaerobic, spore forming pathogen of both humans and animals and is the most common identifiable infectious agent of nosocomial antibiotic-associated diarrhea. Infection can occur following the ingestion and germination of spores, often concurrently with a disruption to the gastrointestinal microbiota, with the resulting disease presenting as a spectrum, ranging from mild and self-limiting diarrhea to severe diarrhea that may progress to life-threating syndromes that include toxic megacolon and pseudomembranous colitis. Disease is induced through the activity of the C. difficile toxins TcdA and TcdB, both of which disrupt the Rho family of GTPases in host cells, causing cell rounding and death and leading to fluid loss and diarrhea. These toxins, despite their functional and structural similarity, do not contribute to disease equally. C. difficile infection (CDI) is made more complex by a high level of strain diversity and the emergence of epidemic strains, including ribotype 027-strains which induce more severe disease in patients. With the changing epidemiology of CDI, our understanding of C. difficile disease, diagnosis, and pathogenesis continues to evolve. This article provides an overview of the current diagnostic tests available for CDI, strain typing, the major toxins C. difficile produces and their mode of action, the host immune response to each toxin and during infection, animal models of disease, and the current treatment and prevention strategies for CDI.
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Affiliation(s)
- S Mileto
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia, 3800
| | - A Das
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia, 3800
| | - D Lyras
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia, 3800
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33
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Status of vaccine research and development for Clostridium difficile. Vaccine 2019; 37:7300-7306. [PMID: 30902484 DOI: 10.1016/j.vaccine.2019.02.052] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 02/21/2019] [Indexed: 12/15/2022]
Abstract
Clostridium difficile associated disease is fundamentally associated with dysbiosis of the gut microbiome as a consequence of antibiotic use. This is because this sporulating, obligate anaerobe germinates and proliferates rapidly in the dysbiotic gut, which is an indirect consequence of their use. During its growth, C. difficile produces two toxins, toxin A (TcdA) and toxin B (TcdB), which are responsible for the majority of clinical symptoms associated with the disease. Three parenterally delivered vaccines, based on detoxified or recombinant forms of these toxins, have undergone or are undergoing clinical trials. Each offers the opportunity to generate high titres of toxin neutralising antibodies. Whilst these data suggest these vaccines may reduce primary symptomatic disease, they do not in their current form reduce the capacity of the organism to persist and shed from the vaccinated host. The current progress of vaccine development is considered with advantages and limitations of each highlighted. In addition, several alternative approaches are described that seek to limit C. difficile germination, colonisation and persistence. It may yet prove that the most effective treatments to limit infection, disease and spread of the organism will require a combination of therapeutic approaches. The potential use and efficacy of these vaccines in low and middle income countries will be depend on the development of a cost effective vaccine and greater understanding of the distribution and extent of disease in these countries.
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Abstract
Bezlotoxumab (Zinplava™) is a fully human monoclonal antibody against Clostridium difficile toxin B indicated for the prevention of C. difficile infection (CDI) recurrence in patients with a high recurrence risk. It is the first agent approved for recurrence prevention and is administered as a single intravenous infusion in conjunction with standard-of-care (SoC) antibacterial treatment for CDI. In well-designed, placebo-controlled, phase 3 trials (MODIFY 1 and 2), a single infusion of bezlotoxumab, given in combination with SoC antibacterial therapy for CDI in adults, was effective in reducing CDI recurrence in the 12 weeks post-treatment, with this benefit being seen mainly in the patients at high recurrence risk. Bezlotoxumab did not impact the efficacy of the antibacterials being used to treat the CDI and, consistent with its benefits on CDI recurrence, appeared to reduce the need for subsequent antibacterials, thus minimizing further gut microbiota disruption. Longer term, there were no further CDI recurrences over 12 months' follow-up among patients who had received bezlotoxumab in MODIFY 2 and entered an extension substudy. Bezlotoxumab has low immunogenicity and is generally well tolerated, although the potential for heart failure in some patients requires consideration; cost-effectiveness data for bezlotoxumab are awaited with interest. Thus, a single intravenous infusion of bezlotoxumab during SoC antibacterial treatment for CDI is an emerging option for reducing CDI recurrence in adults at high risk of recurrence.
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35
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Oral Immunization with Nontoxigenic Clostridium difficile Strains Expressing Chimeric Fragments of TcdA and TcdB Elicits Protective Immunity against C. difficile Infection in Both Mice and Hamsters. Infect Immun 2018; 86:IAI.00489-18. [PMID: 30150259 DOI: 10.1128/iai.00489-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022] Open
Abstract
The symptoms of Clostridium difficile infection (CDI) are attributed largely to two C. difficile toxins, TcdA and TcdB. Significant efforts have been devoted to developing vaccines targeting both toxins through parenteral immunization routes. However, C. difficile is an enteric pathogen, and mucosal/oral immunization would be particularly useful to protect the host against CDI, considering that the gut is the main site of disease onset and progression. Moreover, vaccines directed only against toxins do not target the cells and spores that transmit the disease. Previously, we constructed a chimeric vaccine candidate, mTcd138, comprised of the glucosyltransferase and cysteine proteinase domains of TcdB and the receptor binding domain of TcdA. In this study, to develop an oral vaccine that can target both C. difficile toxins and colonization/adhesion factors, we expressed mTcd138 in a nontoxigenic C. difficile (NTCD) strain, resulting in strain NTCD_mTcd138. Oral immunization with spores of NTCD_mTcd138 provided mice full protection against infection with a hypervirulent C. difficile strain, UK6 (ribotype 027). The protective strength and efficacy of NTCD_mTcd138 were further evaluated in the acute CDI hamster model. Oral immunization with spores of NTCD_mTcd138 also provided hamsters significant protection against infection with 2 × 104 UK6 spores, a dose 200-fold higher than the lethal dose of UK6 in hamsters. These results imply that the genetically modified, nontoxigenic C. difficile strain expressing mTcd138 may represent a novel mucosal vaccine candidate against CDI.
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Oliveira Júnior CA, Silva ROS, Cruz DSG, Pires IH, Guedes RMC, Faria Lobato FC. The non-toxigenic strain of Clostridioides difficile Z31 can prevent infection by C. difficile in experimental model piglets. Anaerobe 2018; 55:24-28. [PMID: 30292822 DOI: 10.1016/j.anaerobe.2018.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/03/2018] [Accepted: 10/03/2018] [Indexed: 12/18/2022]
Abstract
One of the main challenges associated with Clostridioides difficile infection (CDI) in humans and domestic animals is the lack of an effective preventive strategy. One strategy with promising results is the oral administration of non-toxigenic strains of C. difficile (NTCD). Recently, Z31, a NTCD strain isolated from a healthy dog, showed promising results to prevent CDI in hamsters. Thus, the present study aimed to evaluate the capacity of Z31 to prevent CDI in piglets using an experimental model. Twenty neonatal piglets were randomly distributed in three groups: G1 - 106 spores of Z31 followed by 107 spores of a toxigenic C. difficile strain (n = 7), G2 (positive control) - 107 spores of a toxigenic C. difficile strain (n = 7), and G3 (negative control) - no biological inoculum (n = 6). All animals were kept in individual insulators and observed for 60 h. Data regarding clinical signs, macro and microscopic lesions, toxigenic culture of C. difficile, and detection of A/B toxins in the feces were evaluated. All evaluated parameters were significantly lower in animals that received Z31 compared to the positive control. Thus, oral administration of Z31 was able to prevent CDI in piglets in an experimental model.
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Affiliation(s)
- Carlos Augusto Oliveira Júnior
- Veterinary School. Federal University of Minas Gerais (UFMG), Antônio Carlos Avenue, 6627, 31.270-901, Belo Horizonte, MG, Brazil
| | - Rodrigo Otávio Silveira Silva
- Veterinary School. Federal University of Minas Gerais (UFMG), Antônio Carlos Avenue, 6627, 31.270-901, Belo Horizonte, MG, Brazil.
| | - Diogo Soares Gonçalves Cruz
- Veterinary School. Federal University of Minas Gerais (UFMG), Antônio Carlos Avenue, 6627, 31.270-901, Belo Horizonte, MG, Brazil
| | - Isadora Honorato Pires
- Veterinary School. Federal University of Minas Gerais (UFMG), Antônio Carlos Avenue, 6627, 31.270-901, Belo Horizonte, MG, Brazil
| | - Roberto Maurício Carvalho Guedes
- Veterinary School. Federal University of Minas Gerais (UFMG), Antônio Carlos Avenue, 6627, 31.270-901, Belo Horizonte, MG, Brazil
| | - Francisco Carlos Faria Lobato
- Veterinary School. Federal University of Minas Gerais (UFMG), Antônio Carlos Avenue, 6627, 31.270-901, Belo Horizonte, MG, Brazil
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Nagy E, Nagy G, Power CA, Badarau A, Szijártó V. Anti-bacterial Monoclonal Antibodies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1053:119-153. [PMID: 29549638 DOI: 10.1007/978-3-319-72077-7_7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The failing efficacy of antibiotics and the high mortality rate among high-risk patients calls for new treatment modalities for bacterial infections. Due to the vastly divergent pathogenesis of human pathogens, each microbe requires a tailored approach. The main modes of action of anti-bacterial antibodies are virulence factor neutralization, complement-mediated bacterial lysis and enhancement of opsonophagocytic uptake and killing (OPK). Gram-positive bacteria cannot be lysed by complement and their pathogenesis often involves secreted toxins, therefore typically toxin-neutralization and OPK activity are required to prevent and ameliorate disease. In fact, the success stories in terms of approved products, in the anti-bacterial mAb field are based on toxin neutralization (Bacillus anthracis, Clostridium difficile). In contrast, Gram-negative bacteria are vulnerable to antibody-dependent complement-mediated lysis, while their pathogenesis rarely relies on secreted exotoxins, and involves the pro-inflammatory endotoxin (lipopolysaccharide). Given the complexity of bacterial pathogenesis, antibody therapeutics are expected to be most efficient upon targeting more than one virulence factor and/or combining different modes of action. The improved understanding of bacterial pathogenesis combined with the versatility and maturity of antibody discovery technologies available today are pivotal for the design of novel anti-bacterial therapeutics. The intensified research generating promising proof-of-concept data, and the increasing number of clinical programs with anti-bacterial mAbs, indicate that the field is ready to fulfill its promise in the coming years.
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Affiliation(s)
- Eszter Nagy
- Arsanis Biosciences GmbH/Arsanis, Inc, Vienna, Austria.
| | - Gábor Nagy
- Arsanis Biosciences GmbH/Arsanis, Inc, Vienna, Austria
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Schäffler H, Breitrück A. Clostridium difficile - From Colonization to Infection. Front Microbiol 2018; 9:646. [PMID: 29692762 PMCID: PMC5902504 DOI: 10.3389/fmicb.2018.00646] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/19/2018] [Indexed: 12/19/2022] Open
Abstract
Clostridium difficile is the most frequent cause of nosocomial antibiotic-associated diarrhea. The incidence of C. difficile infection (CDI) has been rising worldwide with subsequent increases in morbidity, mortality, and health care costs. Asymptomatic colonization with C. difficile is common and a high prevalence has been found in specific cohorts, e.g., hospitalized patients, adults in nursing homes and in infants. However, the risk of infection with C. difficile differs significantly between these cohorts. While CDI is a clear indication for therapy, colonization with C. difficile is not believed to be a direct precursor for CDI and therefore does not require treatment. Antibiotic therapy causes alterations of the intestinal microbial composition, enabling C. difficile colonization and consecutive toxin production leading to disruption of the colonic epithelial cells. Clinical symptoms of CDI range from mild diarrhea to potentially life-threatening conditions like pseudomembranous colitis or toxic megacolon. While antibiotics are still the treatment of choice for CDI, new therapies have emerged in recent years such as antibodies against C. difficile toxin B and fecal microbial transfer (FMT). This specific therapy for CDI underscores the role of the indigenous bacterial composition in the prevention of the disease in healthy individuals and its role in the pathogenesis after alteration by antibiotic treatment. In addition to the pathogenesis of CDI, this review focuses on the colonization of C. difficile in the human gut and factors promoting CDI.
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Affiliation(s)
- Holger Schäffler
- Division of Gastroenterology, Department of Medicine II, University of Rostock, Rostock, Germany
| | - Anne Breitrück
- Extracorporeal Immunomodulation Unit, Fraunhofer Institute for Cell Therapy and Immunology, Rostock, Germany.,Institute of Medical Microbiology, Virology and Hygiene, University of Rostock, Rostock, Germany
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Posteraro B, Pea F, Masucci L, Posteraro P, Sanguinetti M. Actoxumab + bezlotoxumab combination: what promise for Clostridium difficile treatment? Expert Opin Biol Ther 2018. [PMID: 29534621 DOI: 10.1080/14712598.2018.1452908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Clostridium difficile infection (CDI) is the most common healthcare-associated infection worldwide. As standard CDI antibiotic therapies can result in unacceptably high recurrence rates, novel therapeutic strategies for CDI are necessary. A recently emerged immunological therapy is a monoclonal antibody against C. difficile toxin B. Areas covered: In this review, the authors summarize the available pharmacological, preclinical, and clinical data for the CDI treatment based on anti-toxin A (actoxumab) and anti-toxin B (bezlotoxumab) human monoclonal antibodies (HuMabs), and discuss about the potentiality of a therapy that includes HuMab combined administration for CDI. Expert opinion: Although only bezlotoxumab is indicated to reduce recurrence of CDI, experimental studies using a combination of HuMabs actoxumab and bezlotoxumab have shown that bolstering the host immune response against both the C. difficile toxins may be effective in primary and secondary CDI prevention. Besides neutralizing both the key virulence factors, combination of two HuMabs could potentially offer an advantage for a yet to emerge C. difficile strain, which is a steady threat for patients at high risk of CDI. However, as actoxumab development was halted, passive immunotherapy with actoxumab/bezlotoxumab is actually impracticable. Future research will be needed to assess HuMab combination as a therapeutic strategy in clinical and microbiological cure of CDI.
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Affiliation(s)
- Brunella Posteraro
- a Institute of Public Health (Section of Hygiene) , Università Cattolica del Sacro Cuore, IRCCS Fondazione Policlinico "Agostino Gemelli" , Rome , Italy
| | - Federico Pea
- b Department of Medicine , University of Udine, and Institute of Clinical Pharmacology, Santa Maria della Misericordia University Hospital of Udine , Udine , Italy
| | - Luca Masucci
- c Institute of Microbiology , Università Cattolica del Sacro Cuore, IRCCS Fondazione Policlinico "Agostino Gemelli" , Rome , Italy
| | - Patrizia Posteraro
- d Laboratory of Clinical Pathology and Microbiology , Ospedale San Carlo , Rome , Italy
| | - Maurizio Sanguinetti
- c Institute of Microbiology , Università Cattolica del Sacro Cuore, IRCCS Fondazione Policlinico "Agostino Gemelli" , Rome , Italy
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40
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Bezlotoxumab. INFECTIOUS DISEASES IN CLINICAL PRACTICE 2018. [DOI: 10.1097/ipc.0000000000000571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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41
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Galpérine T, Guery B. Exploring ways to improve CDI outcomes. Med Mal Infect 2018; 48:10-17. [PMID: 29336930 DOI: 10.1016/j.medmal.2017.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 10/23/2017] [Indexed: 12/14/2022]
Abstract
Clostridium difficile is an anaerobic spore-forming Gram-positive bacillus recognized as an evolving international health problem. Metronidazole and vancomycin were - until recently - the only drugs available to treat C. difficile infection (CDI). Better knowledge of the pathophysiology and the development of new drugs completely modified the management of initial episodes and recurrences of CDI. Fidaxomicin significantly reduced recurrences compared with vancomycin. New drugs are also currently evaluated (cadazolid, surotomycin, ridinilazole, rifaximin). Gut microbiota homeostasis was clearly shown to be a key determinant in recurrences as demonstrated by the development of gut microbiota transplantation and alternative microbiota substitution. Passive immunotherapy and vaccinal approaches are also currently being evaluated. In conclusion, CDI treatment has evolved with the development of new therapeutic pathways which now need to be implemented in international guidelines.
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Affiliation(s)
- T Galpérine
- Infectious diseases service, department of medicine, university Hospital, university of Lausanne, 46, rue du Bugnon, 1011 Lausanne, Switzerland
| | - B Guery
- Infectious diseases service, department of medicine, university Hospital, university of Lausanne, 46, rue du Bugnon, 1011 Lausanne, Switzerland.
| | -
- Infectious diseases service, department of medicine, university Hospital, university of Lausanne, 46, rue du Bugnon, 1011 Lausanne, Switzerland
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42
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Abstract
Clostridium difficile is the most frequent cause of nosocomial antibiotic-associated diarrhea. The incidence of C. difficile infection (CDI) has been rising worldwide with subsequent increases in morbidity, mortality, and health care costs. Asymptomatic colonization with C. difficile is common and a high prevalence has been found in specific cohorts, e.g., hospitalized patients, adults in nursing homes and in infants. However, the risk of infection with C. difficile differs significantly between these cohorts. While CDI is a clear indication for therapy, colonization with C. difficile is not believed to be a direct precursor for CDI and therefore does not require treatment. Antibiotic therapy causes alterations of the intestinal microbial composition, enabling C. difficile colonization and consecutive toxin production leading to disruption of the colonic epithelial cells. Clinical symptoms of CDI range from mild diarrhea to potentially life-threatening conditions like pseudomembranous colitis or toxic megacolon. While antibiotics are still the treatment of choice for CDI, new therapies have emerged in recent years such as antibodies against C. difficile toxin B and fecal microbial transfer (FMT). This specific therapy for CDI underscores the role of the indigenous bacterial composition in the prevention of the disease in healthy individuals and its role in the pathogenesis after alteration by antibiotic treatment. In addition to the pathogenesis of CDI, this review focuses on the colonization of C. difficile in the human gut and factors promoting CDI.
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Affiliation(s)
- Holger Schäffler
- Division of Gastroenterology, Department of Medicine II, University of Rostock, Rostock, Germany
| | - Anne Breitrück
- Extracorporeal Immunomodulation Unit, Fraunhofer Institute for Cell Therapy and Immunology, Rostock, Germany
- Institute of Medical Microbiology, Virology and Hygiene, University of Rostock, Rostock, Germany
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43
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Kroh HK, Chandrasekaran R, Zhang Z, Rosenthal K, Woods R, Jin X, Nyborg AC, Rainey GJ, Warrener P, Melnyk RA, Spiller BW, Lacy DB. A neutralizing antibody that blocks delivery of the enzymatic cargo of Clostridium difficile toxin TcdB into host cells. J Biol Chem 2017; 293:941-952. [PMID: 29180448 DOI: 10.1074/jbc.m117.813428] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 11/08/2017] [Indexed: 12/14/2022] Open
Abstract
Clostridium difficile infection is the leading cause of hospital-acquired diarrhea and is mediated by the actions of two toxins, TcdA and TcdB. The toxins perturb host cell function through a multistep process of receptor binding, endocytosis, low pH-induced pore formation, and the translocation and delivery of an N-terminal glucosyltransferase domain that inactivates host GTPases. Infection studies with isogenic strains having defined toxin deletions have established TcdB as an important target for therapeutic development. Monoclonal antibodies that neutralize TcdB function have been shown to protect against C. difficile infection in animal models and reduce recurrence in humans. Here, we report the mechanism of TcdB neutralization by PA41, a humanized monoclonal antibody capable of neutralizing TcdB from a diverse array of C. difficile strains. Through a combination of structural, biochemical, and cell functional studies, involving X-ray crystallography and EM, we show that PA41 recognizes a single, highly conserved epitope on the TcdB glucosyltransferase domain and blocks productive translocation and delivery of the enzymatic cargo into the host cell. Our study reveals a unique mechanism of C. difficile toxin neutralization by a monoclonal antibody, which involves targeting a process that is conserved across the large clostridial glucosylating toxins. The PA41 antibody described here provides a valuable tool for dissecting the mechanism of toxin pore formation and translocation across the endosomal membrane.
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Affiliation(s)
- Heather K Kroh
- From the Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2363
| | - Ramyavardhanee Chandrasekaran
- From the Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2363
| | - Zhifen Zhang
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | | | - Rob Woods
- MedImmune LLC, Gaithersburg, Maryland 20878-2204
| | - Xiaofang Jin
- MedImmune LLC, Gaithersburg, Maryland 20878-2204
| | | | | | | | - Roman A Melnyk
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Benjamin W Spiller
- From the Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2363.,Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-6600, and
| | - D Borden Lacy
- From the Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2363, .,Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee 37212-2637
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44
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Chandrasekaran R, Lacy DB. The role of toxins in Clostridium difficile infection. FEMS Microbiol Rev 2017; 41:723-750. [PMID: 29048477 PMCID: PMC5812492 DOI: 10.1093/femsre/fux048] [Citation(s) in RCA: 200] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/10/2017] [Indexed: 02/06/2023] Open
Abstract
Clostridium difficile is a bacterial pathogen that is the leading cause of nosocomial antibiotic-associated diarrhea and pseudomembranous colitis worldwide. The incidence, severity, mortality and healthcare costs associated with C. difficile infection (CDI) are rising, making C. difficile a major threat to public health. Traditional treatments for CDI involve use of antibiotics such as metronidazole and vancomycin, but disease recurrence occurs in about 30% of patients, highlighting the need for new therapies. The pathogenesis of C. difficile is primarily mediated by the actions of two large clostridial glucosylating toxins, toxin A (TcdA) and toxin B (TcdB). Some strains produce a third toxin, the binary toxin C. difficile transferase, which can also contribute to C. difficile virulence and disease. These toxins act on the colonic epithelium and immune cells and induce a complex cascade of cellular events that result in fluid secretion, inflammation and tissue damage, which are the hallmark features of the disease. In this review, we summarize our current understanding of the structure and mechanism of action of the C. difficile toxins and their role in disease.
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Affiliation(s)
- Ramyavardhanee Chandrasekaran
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - D. Borden Lacy
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- The Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37232, USA
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45
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Grześkowiak Ł, Martínez-Vallespín B, Dadi TH, Radloff J, Amasheh S, Heinsen FA, Franke A, Reinert K, Vahjen W, Zentek J, Pieper R. Formula Feeding Predisposes Neonatal Piglets to Clostridium difficile Gut Infection. J Infect Dis 2017; 217:1442-1452. [DOI: 10.1093/infdis/jix567] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/24/2017] [Indexed: 12/20/2022] Open
Affiliation(s)
| | | | - Temesgen H Dadi
- Department of Mathematics and Computer Science, Institute of Computer Science, Kiel, Germany
- Max Planck Institute for Molecular Genetics, Berlin, Kiel, Germany
| | - Judith Radloff
- Institute of Veterinary Physiology, Freie Universität Berlin, Kiel, Germany
| | - Salah Amasheh
- Institute of Veterinary Physiology, Freie Universität Berlin, Kiel, Germany
| | - Femke-Anouska Heinsen
- Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, University Hospital Schleswig Holstein, Kiel, Germany
| | - Andre Franke
- Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, University Hospital Schleswig Holstein, Kiel, Germany
| | - Knut Reinert
- Department of Mathematics and Computer Science, Institute of Computer Science, Kiel, Germany
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Kufel WD, Devanathan AS, Marx AH, Weber DJ, Daniels LM. Bezlotoxumab: A Novel Agent for the Prevention of Recurrent Clostridium difficile Infection. Pharmacotherapy 2017; 37:1298-1308. [PMID: 28730660 DOI: 10.1002/phar.1990] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During the past decade, the incidence and severity of Clostridium difficile infection (CDI) have significantly increased, leading to a rise in CDI-associated hospitalizations, health care costs, and mortality. Although treatment options exist for CDI, recurrence is frequent following treatment. Furthermore, patients with at least one CDI recurrence are at an increased risk of developing additional recurrences. A novel approach to the prevention of recurrent CDI is the use of monoclonal antibodies directed against the toxins responsible for CDI as an adjunct to antibiotic treatment. Bezlotoxumab, a human monoclonal antibody that binds and neutralizes C. difficile toxin B, is the first therapeutic agent to receive United States Food and Drug Administration approval for the prevention of CDI recurrence. Clinical studies have demonstrated superior efficacy of bezlotoxumab in adults receiving antibiotic therapy for CDI compared with antibiotic therapy alone for the prevention of CDI recurrence. Bezlotoxumab was well tolerated in clinical trials, with the most common adverse effects being nausea, vomiting, fatigue, pyrexia, headache, and diarrhea. The demonstrated efficacy, safety, and characteristics of bezlotoxumab present an advance in prevention of CDI recurrence.
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Affiliation(s)
- Wesley D Kufel
- Department of Pharmacy, University of North Carolina Medical Center, Chapel Hill, North Carolina.,Department of Practice Advancement and Clinical Education, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, North Carolina
| | - Aaron S Devanathan
- Department of Pharmacy, University of North Carolina Medical Center, Chapel Hill, North Carolina.,Department of Practice Advancement and Clinical Education, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, North Carolina
| | - Ashley H Marx
- Department of Pharmacy, University of North Carolina Medical Center, Chapel Hill, North Carolina.,Department of Practice Advancement and Clinical Education, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, North Carolina
| | - David J Weber
- Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Lindsay M Daniels
- Department of Pharmacy, University of North Carolina Medical Center, Chapel Hill, North Carolina.,Department of Practice Advancement and Clinical Education, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, North Carolina
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47
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Shin JH, Warren CA. Collateral damage during antibiotic treatment of C. difficile infection in the aged host: Insights into why recurrent disease happens. Gut Microbes 2017; 8:504-510. [PMID: 28453386 PMCID: PMC5628656 DOI: 10.1080/19490976.2017.1323616] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 04/18/2017] [Accepted: 04/21/2017] [Indexed: 02/03/2023] Open
Abstract
Clostridium difficile infection (CDI) is one of the most common causes of healthcare-associated infections but an even bigger problem for the aging population. Advanced age leads to higher incidence, higher mortality, and higher recurrences. In our study, recently published in the Journal of Infectious Diseases, we investigated the effect of aging on CDI using a mouse model. We were able to demonstrate that aging leads to worse clinical outcomes, as well as lead to changes in microbiota composition and lower antibody production against C. difficile toxin A, but not toxin B. An association between advanced age and lower antibody production against C. difficile is a new finding which would explain the effect of aging on CDI outcome. Vancomycin, an anti-C. difficile antibiotic, led to similar changes in antibody response, suggesting a connection between microbiome and antibody response in the context of aging, which would require a much more nuanced look at the treatment of CDI.
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Affiliation(s)
- Jae Hyun Shin
- University of Virginia School of Medicine, Department of Medicine, Division of Infectious Diseases and International Health
| | - Cirle A. Warren
- University of Virginia School of Medicine, Department of Medicine, Division of Infectious Diseases and International Health
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48
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Gupta P, Zhang Z, Sugiman-Marangos SN, Tam J, Raman S, Julien JP, Kroh HK, Lacy DB, Murgolo N, Bekkari K, Therien AG, Hernandez LD, Melnyk RA. Functional defects in Clostridium difficile TcdB toxin uptake identify CSPG4 receptor-binding determinants. J Biol Chem 2017; 292:17290-17301. [PMID: 28842504 DOI: 10.1074/jbc.m117.806687] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 08/11/2017] [Indexed: 12/11/2022] Open
Abstract
Clostridium difficile is a major nosocomial pathogen that produces two exotoxins, TcdA and TcdB, with TcdB thought to be the primary determinant in human disease. TcdA and TcdB are large, multidomain proteins, each harboring a cytotoxic glucosyltransferase domain that is delivered into the cytosol from endosomes via a translocation domain after receptor-mediated endocytosis of toxins from the cell surface. Although there are currently no known host cell receptors for TcdA, three cell-surface receptors for TcdB have been identified: CSPG4, NECTIN3, and FZD1/2/7. The sites on TcdB that mediate binding to each receptor are not defined. Furthermore, it is not known whether the combined repetitive oligopeptide (CROP) domain is involved in or required for receptor binding. Here, in a screen designed to identify sites in TcdB that are essential for target cell intoxication, we identified a region at the junction of the translocation and the CROP domains that is implicated in CSPG4 binding. Using a series of C-terminal truncations, we show that the CSPG4-binding site on TcdB extends into the CROP domain, requiring three short repeats for binding and for full toxicity on CSPG4-expressing cells. Consistent with the location of the CSPG4-binding site on TcdB, we show that the anti-TcdB antibody bezlotoxumab, which binds partially within the first three short repeats, prevents CSPG4 binding to TcdB. In addition to establishing the binding region for CSPG4, this work ascribes for the first time a role in TcdB CROPs in receptor binding and further clarifies the relative roles of host receptors in TcdB pathogenesis.
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Affiliation(s)
- Pulkit Gupta
- From Merck & Co., Inc., Kenilworth, New Jersey 07033
| | - Zhifen Zhang
- Molecular Medicine, The Hospital for Sick Children, Ontario M5G 0A4, Canada.,the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
| | | | - John Tam
- Molecular Medicine, The Hospital for Sick Children, Ontario M5G 0A4, Canada
| | - Swetha Raman
- Molecular Medicine, The Hospital for Sick Children, Ontario M5G 0A4, Canada
| | - Jean-Phillipe Julien
- Molecular Medicine, The Hospital for Sick Children, Ontario M5G 0A4, Canada.,the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
| | - Heather K Kroh
- the Departments of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37212
| | - D Borden Lacy
- the Departments of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37212
| | | | | | | | | | - Roman A Melnyk
- Molecular Medicine, The Hospital for Sick Children, Ontario M5G 0A4, Canada, .,the Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
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Amino Acid Differences in the 1753-to-1851 Region of TcdB Influence Variations in TcdB1 and TcdB2 Cell Entry. mSphere 2017; 2:mSphere00268-17. [PMID: 28776043 PMCID: PMC5541160 DOI: 10.1128/msphere.00268-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/13/2017] [Indexed: 01/24/2023] Open
Abstract
Clostridium difficile TcdB2 enters cells with a higher efficiency than TcdB1 and exhibits an overall higher level of toxicity. However, the TcdB2-specific sequences that account for more efficient cell entry have not been reported. In this study, we examined the contribution of carboxy-terminal sequence differences to TcdB activity by comparing the binding, uptake, and endosomal localization of TcdB1 and TcdB2 or selected recombinant fragments of these proteins. Our findings suggest that sequence differences in the amino acid 1753 to 1851 region proximal to the combined repetitive oligopeptide domain (CROP) support enhanced uptake of TcdB2 and localization of toxin in acidified endosomes. In the absence of this region, the CROP domains of both forms of the toxin exhibited similar levels of cell interaction, while the addition of amino acids 1753 to 1851 greatly increased toxin binding by only TcdB2. Moreover, the amino acid 1753 to 2366 fragment of TcdB2, but not TcdB1, accumulated to detectable levels in acidified endosomes. Unexpectedly, we discovered an unusual relationship between endocytosis and the efficiency of cell binding for TcdB1 and TcdB2 wherein inhibition of endocytosis by a chemical inhibitor or incubation at a low temperature resulted in a dramatic reduction in cell binding. These findings provide information on sequence variations that may contribute to differences in TcdB1 and TcdB2 toxicity and reveal a heretofore unknown connection between endocytosis and cell binding for this toxin. IMPORTANCE TcdB is a major virulence factor produced by Clostridium difficile, a leading cause of antibiotic-associated diarrhea. Hypervirulent strains of C. difficile encode a variant of TcdB (TcdB2) that is more toxic than toxin derived from historical strains (TcdB1). Though TcdB1 and TcdB2 exhibit 92% overall identity, a 99-amino-acid region previously associated with cell entry and spanning amino acids 1753 to 1851 has only 77% sequence identity. Results from the present study indicate that the substantial sequence variation in this region could contribute to the differences in cell entry between TcdB1 and TcdB2 and possibly explain TcdB2's heightened toxicity. Finally, during the course of these studies, an unusual aspect of TcdB cell entry was discovered wherein cell binding appeared to depend on endocytosis. These findings provide insight into TcdB's variant forms and their mechanisms of cell entry.
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Darkoh C, Deaton M, DuPont HL. Nonantimicrobial drug targets for Clostridium difficile infections. Future Microbiol 2017; 12:975-985. [PMID: 28759258 DOI: 10.2217/fmb-2017-0024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile infection (CDI) is a major public health problem worldwide. Treatment has become complicated due to the emergence of strains with increased toxigenicity and sporulation rate, together with rampant antibiotics use that disrupts colonization resistance of the colonic microbiota. As a result, there is a critical need for nonantibiotic treatments. Therapies based on inhibiting the toxins, bacterial structures responsible for colonization, virulence and restoration of the gut microbiota are the most important nonantibiotic targets to combat CDI. This report outlines these targets and how they could become the focus of future therapeutic agents. Inhibiting colonization and virulence factors during CDI will disrupt pathogen persistence and decrease exposure to the inflammatory toxins, allowing the immune system to clear the infection.
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Affiliation(s)
- Charles Darkoh
- Department of Epidemiology, Human Genetics, & Environmental Sciences, Center For Infectious Diseases, School of Public Health, University of Texas Health Science Center, Houston, TX 77030, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Microbiology & Infectious Diseases Program, Houston, TX 77030, USA
| | - Magdalena Deaton
- Department of Epidemiology, Human Genetics, & Environmental Sciences, Center For Infectious Diseases, School of Public Health, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Herbert L DuPont
- Department of Epidemiology, Human Genetics, & Environmental Sciences, Center For Infectious Diseases, School of Public Health, University of Texas Health Science Center, Houston, TX 77030, USA.,Baylor College of Medicine, Departments of Molecular Virology & Microbiology & Medicine, Houston, TX 77030, USA
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