Heparin Mimics Extracellular DNA in Binding to Cell Surface-Localized Proteins and Promoting <named-content content-type="genus-species">Staphylococcus aureus</named-content> Biofilm Formation

ABSTRACT Staphylococcus aureus is a leading cause of catheter-related bloodstream infections. Biofilms form on these implants and are held together by a matrix composed of proteins, polysaccharides, and extracellular DNA (eDNA). Heparin is a sulfated glycosaminoglycan that is routinely used in centr...

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Main Authors: Surabhi Mishra, Alexander R. Horswill
Format: Article
Language:English
Published: American Society for Microbiology 2017-06-01
Series:mSphere
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/mSphere.00135-17
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author Surabhi Mishra
Alexander R. Horswill
author_facet Surabhi Mishra
Alexander R. Horswill
author_sort Surabhi Mishra
collection DOAJ
description ABSTRACT Staphylococcus aureus is a leading cause of catheter-related bloodstream infections. Biofilms form on these implants and are held together by a matrix composed of proteins, polysaccharides, and extracellular DNA (eDNA). Heparin is a sulfated glycosaminoglycan that is routinely used in central venous catheters to prevent thrombosis, but it has been shown to stimulate S. aureus biofilm formation through an unknown mechanism. Data presented here reveal that heparin enhances biofilm capacity in many S. aureus and coagulase-negative staphylococcal strains, and it is incorporated into the USA300 methicillin-resistant S. aureus (MRSA) biofilm matrix. The S. aureus USA300 biofilms containing heparin are sensitive to proteinase K treatment, which suggests that proteins have an important structural role during heparin incorporation. Multiple heparin-binding proteins were identified by proteomics of the secreted and cell wall fractions. Proteins known to contribute to biofilm were identified, and some proteins were reported to have the ability to bind eDNA, such as the major autolysin (Atl) and the immunodominant surface protein B (IsaB). Mutants defective in IsaB showed a moderate decrease in biofilm capacity in the presence of heparin. Our findings suggested that heparin is substituting for eDNA during S. aureus biofilm development. To test this model, eDNA content was increased in biofilms through inactivation of nuclease activity, and the heparin enhancement effect was attenuated. Collectively, these data support the hypothesis that S. aureus can incorporate heparin into the matrix and enhance biofilm capacity by taking advantage of existing eDNA-binding proteins. IMPORTANCE Staphylococcus aureus and coagulase-negative staphylococci (CoNS) are the leading causes of catheter implant infections. Identifying the factors that stimulate catheter infection and the mechanism involved is important for preventing such infections. Heparin, the main component of catheter lock solutions, has been shown previously to stimulate S. aureus biofilm formation through an unknown pathway. This work identifies multiple heparin-binding proteins in S. aureus, and it reveals a potential mechanism through which heparin enhances biofilm capacity. Understanding the details of the heparin enhancement effect could guide future use of appropriate lock solutions for catheter implants.
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spelling doaj.art-ad88d31f12e94b5b94ef04223697329c2022-12-21T22:54:35ZengAmerican Society for MicrobiologymSphere2379-50422017-06-012310.1128/mSphere.00135-17Heparin Mimics Extracellular DNA in Binding to Cell Surface-Localized Proteins and Promoting <named-content content-type="genus-species">Staphylococcus aureus</named-content> Biofilm FormationSurabhi Mishra0Alexander R. Horswill1Department of Microbiology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USADepartment of Microbiology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USAABSTRACT Staphylococcus aureus is a leading cause of catheter-related bloodstream infections. Biofilms form on these implants and are held together by a matrix composed of proteins, polysaccharides, and extracellular DNA (eDNA). Heparin is a sulfated glycosaminoglycan that is routinely used in central venous catheters to prevent thrombosis, but it has been shown to stimulate S. aureus biofilm formation through an unknown mechanism. Data presented here reveal that heparin enhances biofilm capacity in many S. aureus and coagulase-negative staphylococcal strains, and it is incorporated into the USA300 methicillin-resistant S. aureus (MRSA) biofilm matrix. The S. aureus USA300 biofilms containing heparin are sensitive to proteinase K treatment, which suggests that proteins have an important structural role during heparin incorporation. Multiple heparin-binding proteins were identified by proteomics of the secreted and cell wall fractions. Proteins known to contribute to biofilm were identified, and some proteins were reported to have the ability to bind eDNA, such as the major autolysin (Atl) and the immunodominant surface protein B (IsaB). Mutants defective in IsaB showed a moderate decrease in biofilm capacity in the presence of heparin. Our findings suggested that heparin is substituting for eDNA during S. aureus biofilm development. To test this model, eDNA content was increased in biofilms through inactivation of nuclease activity, and the heparin enhancement effect was attenuated. Collectively, these data support the hypothesis that S. aureus can incorporate heparin into the matrix and enhance biofilm capacity by taking advantage of existing eDNA-binding proteins. IMPORTANCE Staphylococcus aureus and coagulase-negative staphylococci (CoNS) are the leading causes of catheter implant infections. Identifying the factors that stimulate catheter infection and the mechanism involved is important for preventing such infections. Heparin, the main component of catheter lock solutions, has been shown previously to stimulate S. aureus biofilm formation through an unknown pathway. This work identifies multiple heparin-binding proteins in S. aureus, and it reveals a potential mechanism through which heparin enhances biofilm capacity. Understanding the details of the heparin enhancement effect could guide future use of appropriate lock solutions for catheter implants.https://journals.asm.org/doi/10.1128/mSphere.00135-17heparinStaphylococcus aureusbiofilmeDNAglycosaminoglycanMRSA
spellingShingle Surabhi Mishra
Alexander R. Horswill
Heparin Mimics Extracellular DNA in Binding to Cell Surface-Localized Proteins and Promoting <named-content content-type="genus-species">Staphylococcus aureus</named-content> Biofilm Formation
mSphere
heparin
Staphylococcus aureus
biofilm
eDNA
glycosaminoglycan
MRSA
title Heparin Mimics Extracellular DNA in Binding to Cell Surface-Localized Proteins and Promoting <named-content content-type="genus-species">Staphylococcus aureus</named-content> Biofilm Formation
title_full Heparin Mimics Extracellular DNA in Binding to Cell Surface-Localized Proteins and Promoting <named-content content-type="genus-species">Staphylococcus aureus</named-content> Biofilm Formation
title_fullStr Heparin Mimics Extracellular DNA in Binding to Cell Surface-Localized Proteins and Promoting <named-content content-type="genus-species">Staphylococcus aureus</named-content> Biofilm Formation
title_full_unstemmed Heparin Mimics Extracellular DNA in Binding to Cell Surface-Localized Proteins and Promoting <named-content content-type="genus-species">Staphylococcus aureus</named-content> Biofilm Formation
title_short Heparin Mimics Extracellular DNA in Binding to Cell Surface-Localized Proteins and Promoting <named-content content-type="genus-species">Staphylococcus aureus</named-content> Biofilm Formation
title_sort heparin mimics extracellular dna in binding to cell surface localized proteins and promoting named content content type genus species staphylococcus aureus named content biofilm formation
topic heparin
Staphylococcus aureus
biofilm
eDNA
glycosaminoglycan
MRSA
url https://journals.asm.org/doi/10.1128/mSphere.00135-17
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