Mishra Surabhi, Horswill Alexander R
Department of Microbiology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA.
Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa, USA.
mSphere. 2017 Jun 21;2(3). doi: 10.1128/mSphere.00135-17. eCollection 2017 May-Jun.
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 biofilm formation through an unknown mechanism. Data presented here reveal that heparin enhances biofilm capacity in many and coagulase-negative staphylococcal strains, and it is incorporated into the USA300 methicillin-resistant (MRSA) biofilm matrix. The . 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 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 can incorporate heparin into the matrix and enhance biofilm capacity by taking advantage of existing eDNA-binding proteins. 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 biofilm formation through an unknown pathway. This work identifies multiple heparin-binding proteins in , 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.
是导管相关血流感染的主要原因。生物膜在这些植入物上形成，并由蛋白质、多糖和细胞外DNA（eDNA）组成的基质维系在一起。肝素是一种硫酸化糖胺聚糖，常用于中心静脉导管以预防血栓形成，但已表明它会通过未知机制刺激生物膜形成。此处呈现的数据表明，肝素可增强多种金黄色葡萄球菌和凝固酶阴性葡萄球菌菌株的生物膜形成能力，并且它会整合到USA300耐甲氧西林金黄色葡萄球菌（MRSA）生物膜基质中。含有肝素的USA300生物膜对蛋白酶K处理敏感，这表明蛋白质在肝素整合过程中具有重要的结构作用。通过对分泌和细胞壁组分进行蛋白质组学分析，鉴定出了多种肝素结合蛋白。已鉴定出已知有助于生物膜形成的蛋白质，并且据报道一些蛋白质具有结合eDNA的能力，例如主要自溶素（Atl）和免疫显性表面蛋白B（IsaB）。IsaB缺陷型突变体在存在肝素的情况下生物膜形成能力出现适度下降。我们的研究结果表明，在生物膜形成过程中肝素正在替代eDNA。为了验证该模型，通过使核酸酶失活来增加生物膜中的eDNA含量，肝素增强效应减弱。总体而言，这些数据支持以下假设：金黄色葡萄球菌可利用现有的eDNA结合蛋白将肝素整合到基质中并增强生物膜形成能力。金黄色葡萄球菌和凝固酶阴性葡萄球菌（CoNS）是导管植入感染的主要原因。确定刺激导管感染的因素及其涉及的机制对于预防此类感染很重要。肝素是导管封管液的主要成分，先前已表明它会通过未知途径刺激生物膜形成。这项工作鉴定出了金黄色葡萄球菌中的多种肝素结合蛋白，并揭示了肝素增强生物膜形成能力的潜在机制。了解肝素增强效应的细节可为未来导管植入适用封管液的使用提供指导。
