Development of Anti-Biofilm Agents that Target Staphylococcal Biofilms

项目总结（见说明）： 金黄色葡萄球菌是医院感染的主要病原体，通常是由于留置器械上的生物膜形成。一旦生物膜在这些表面上生长，它们就很难被根除，因为组成细胞对许多抗生素的耐药性增加。这一点，加上事实上，很大比例的S。在感染中鉴定的金黄色葡萄球菌分离株现在具有针对包括甲氧西林和万古霉素（MRSA，VRSA）在内的多种抗生素的抗性基因，这清楚地表明需要开发对抗葡萄球菌生物膜相关感染的新方法。这个哈佛大学范围内的MRSA新治疗合作项目的子项目集中于开发针对葡萄球菌生物膜的抗生物膜剂。我们最近发现了两种不同的抑制生物膜形成的机制，在广泛的生物体，包括S。金黄色。第一种机制是基于以下发现：细菌在涉及不寻常脂质的功能微区中组织许多膜相关过程，即细菌具有类似于真核细胞中发现的脂筏。干扰这些常见脂质的合成可以导致完全消除生物膜形成，而不会对细胞产生致命影响。 第二个发现是细菌在生物膜的生命周期后期产生D-氨基酸，并且这些氨基酸被掺入肽聚糖中，结果是细胞从生物膜基质中释放，从而生物膜被分解。虽然这些过程已经在枯草芽孢杆菌中进行了详细的分析，但对脂质合成抑制剂或D-氨基酸阻止S.金黄色。为此，我们拟：1）鉴定S.金黄色葡萄球菌，并确定抗脂筏剂抑制生物膜形成的机制，和2）确定D-氨基酸影响S.金黄色葡萄球菌生物膜

PROJECT SUMMARY (See instructions): Staphylococcus aureus is key pathogen involved in nosocomial infections, frequently due to biofilm formation on indwelling devices. Once biofilms grow on these surfaces they are difficult to eradicate because the constituent cells display increased resistance to many antibiotics. This, combined with the fact that a large percentage of S. aureus isolates identified in infections now harbor resistance genes against numerous antibiotics including methicillin and vancomycin (MRSA, VRSA), makes it clear that new ways of combating staphyloccocal biofilm-associated infections need to be developed. This subproject ofthe Harvard-wide collaborative project for new MRSA treatments is focused on the development of anti-biofilm agents that target staphyloccocal biofilms. We have recently discovered two distinct mechanisms for inhibiting biofilm formation in a broad range of organisms, including S. aureus. The first mechanism is based on the finding that bacteria organize many membrane-related processes in functional microdomains that involve unusual lipids, i.e. bacteria have lipid rafts akin to those is found in eukaryotic cells. Interfering with the synthesis of these usual lipids can lead to complete elimination of biofilm formation without a lethal effect on the cells. The second discovery is that bacteria produce D-amino acids late in the life cycle of a biofilm and that these amino acids are incorporated into the peptidoglycan with the consequence that cells are released from the biofilm matrix and the biofilm is thus disassembled. While these processes have been analyzed in detail in the bacterium Bacillus subtilis, little is known about the mechanisms by which lipid synthesis inhibitors or Damino acids prevent biofilm formation in S. aureus. To this end, we propose to: 1) Identify the lipid raft fomiation pathway in S. aureus and determine the mechanism through which anti-lipid raft agents inhibit biofilm formation, and 2) Determine the molecular mechanism through which D-amino acids affect S. aureus biofilms.