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The binary toxin CDT enhances Clostridium difficile virulence by suppressing protective colonic eosinophilia

Nature Microbiology volume 1, Article number: 16108 (2016) | Download Citation

Abstract

Clostridium difficile is the most common hospital acquired pathogen in the USA, and infection is, in many cases, fatal. Toxins A and B are its major virulence factors, but expression of a third toxin, known as C. difficile transferase (CDT), is increasingly common. An adenosine diphosphate (ADP)-ribosyltransferase that causes actin cytoskeletal disruption, CDT is typically produced by the major, hypervirulent strains and has been associated with more severe disease. Here, we show that CDT enhances the virulence of two PCR-ribotype 027 strains in mice. The toxin induces pathogenic host inflammation via a Toll-like receptor 2 (TLR2)-dependent pathway, resulting in the suppression of a protective host eosinophilic response. Finally, we show that restoration of TLR2-deficient eosinophils is sufficient for protection from a strain producing CDT. These findings offer an explanation for the enhanced virulence of CDT-expressing C. difficile and demonstrate a mechanism by which this binary toxin subverts the host immune response.

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Acknowledgements

The authors thank the UVA Research Histology and Flow Cytometry Cores for their assistance with sample preparation and analysis. The authors acknowledge TechLab for providing purified toxins A and B and TOX A/B ELISA kits. The authors thank A. Criss, J. Casanova, U. Lorenz and M. Kendall for discussions. C.A.C. was supported by the Robert R. Wagner Fellowship from the University of Virginia School of Medicine and by NIH training grant 5T32AI07046-38. E.L.B. was supported by NIH grants T32AI07496 and F31AI114203. M.M.S. was supported by NIH grant 2T32GM008715-16. D.L. was supported by Future Fellowship FT120100779 (from the Australian Research Council). This work was supported by NIH grants R01AI124214, R01AI026649 and R21AI114734 to W.A.P.

Author information

Affiliations

  1. Departments of Microbiology, Immunology and Cancer Biology, University of Virginia Health System, Charlottesville, Virginia 22908 USA

    • Carrie A. Cowardin
    • , Erica L. Buonomo
    • , Mahmoud M. Saleh
    • , Madeline G. Wilson
    • , Stacey L. Burgess
    •  & William A. Petri Jr
  2. Clostridia Research Group, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK

    • Sarah A. Kuehne
    •  & Nigel P. Minton
  3. Institute of Experimental and Clinical Pharmacology and Toxicology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany

    • Carsten Schwan
    •  & Klaus Aktories
  4. Institute of Immunology, University Medical Center Hamburg-Eppendorf, D20246 Hamburg, Germany

    • Anna M. Eichhoff
    •  & Friedrich Koch-Nolte
  5. Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, and Monash University, Victoria 3800, Australia

    • Dena Lyras
  6. Departments of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908 USA

    • William A. Petri Jr
  7. Departments of Pathology, University of Virginia Health System, Charlottesville, Virginia 22908, USA

    • William A. Petri Jr

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Contributions

C.A.C. conceived and designed the experiments, performed the experiments, analysed the data and wrote the paper. E.L.B. performed the experiments, provided valuable advice and contributed materials. M.M.S., M.G.W. and S.L.B performed the experiments. S.A.K., C.S., A.M.E., F.K.-N., D.L., K.A. and N.P.M. contributed materials and valuable advice on experimental design. W.A.P. assisted with the experimental design and edited the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to William A. Petri Jr.

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DOI

https://doi.org/10.1038/nmicrobiol.2016.108

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