Role of spx in biofilm formation of Staphylococcus epidermidis

Authors

  • Chongzhen Wang,

    1. Key Laboratory of Medical Molecular Virology, Institute of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University, Shanghai, China
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  • Jiajia Fan,

    1. Key Laboratory of Medical Molecular Virology, Institute of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University, Shanghai, China
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  • Chen Niu,

    1. Key Laboratory of Medical Molecular Virology, Institute of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University, Shanghai, China
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  • Chuan Wang,

    1. Key Laboratory of Medical Molecular Virology, Institute of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University, Shanghai, China
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  • Amer E. Villaruz,

    1. National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD, USA
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  • Michael Otto,

    1. National Institute of Allergy and Infectious Diseases, The National Institutes of Health, Bethesda, MD, USA
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  • Qian Gao

    1. Key Laboratory of Medical Molecular Virology, Institute of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University, Shanghai, China
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  • Editor: Richard Marconi

Correspondence: Qian Gao, Key Laboratory of Medical Molecular Virology, Institute of Biomedical Sciences and Institute of Medical Microbiology, Shanghai Medical College, Fudan University, 138 Yi Xue Yuan Road, Shanghai 200032, China. Tel./fax: +86 21 5423 7195; e-mail: qgao99@yahoo.com

Abstract

Infections caused by the leading nosocomial pathogen Staphylococcus epidermidis are characterized by biofilm formation on implanted medical devices. In a previous study, we found that ClpP protease plays an essential role in biofilm formation of S. epidermidis. However, the mechanism by which ClpP impacts S. epidermidis biofilms has remained unknown. Here, we show that the Spx protein accumulates in the clpP mutant strain of S. epidermidis and controls biofilm formation of S. epidermidis via a pronounced effect on the transcription of the icaADBC operon coding for the production of the biofilm exopolysaccharide polysaccharide intercellular adhesion (PIA). Notably, in contrast to Staphylococcus aureus, Spx controls PIA expression via an icaR-independent mechanism. Furthermore, Spx affected primary surface attachment, although not by regulating the production of the autolysin AtlE. Our results indicate that ClpP enhances the formation of S. epidermidis biofilms by degrading Spx, a negative regulator of biofilm formation.

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