The role of ionic interactions in the adherence of the Staphylococcus epidermidis adhesin SdrF to prosthetic material

Authors

  • Faustino A. Toba,

    1. Division of Infectious Diseases, Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
    Current affiliation:
    1. Medical Instill Technologies Inc., New Milford, CT, USA
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  • Livia Visai,

    1. Department of Molecular Medicine, Center for Tissue Engineering (C.I.T.), University of Pavia, Pavia, Italy
    2. Salvatore Maugeri Foundation IRCCS, Pavia, Italy
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  • Sheetal Trivedi,

    1. Division of Infectious Diseases, Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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  • Franklin D. Lowy

    Corresponding author
    1. Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
    • Division of Infectious Diseases, Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Correspondence: Franklin D. Lowy, Department of Medicine and Pathology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA. Tel.: +212 305 5787; Fax: +212 305 5794; e-mail: fl189@columbia.edu

Abstract

Staphylococcus epidermidis infections are common complications of prosthetic device implantation. SdrF, a surface protein, appears to play a critical role in the initial colonization step by adhering to type I collagen and Dacron™. The role of ionic interactions in S. epidermidis adherence to prosthetic material was examined. SdrF was cloned and expressed in Lactococcus lactis. The effect of pH, cation concentration, and detergents on adherence to different types of plastic surfaces was assessed by crystal violet staining and bacterial cell counting. SdrF, in contrast with controls and other S. epidermidis surface proteins, bound to hydrophobic materials such as polystyrene. Binding was an ionic interaction and was affected by surface charge of the plastic, pH, and cation concentration. Adherence of the SdrF construct was increased to positively charged plastics and was reduced by increasing concentrations of Ca2+ and Na+. Binding was optimal at pH 7.4. Kinetic studies demonstrated that the SdrF B domain as well as one of the B subdomains was sufficient to mediate binding. The SdrF construct also bound more avidly to Goretex™ than the lacotococcal control. SdrF is a multifunctional protein that contributes to prosthetic devices infections by ionic, as well as specific receptor–ligand interactions.

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