细菌菌群间的相互作用对表皮葡萄球菌生物膜形成的影响 - fdurop.doc

项目编号：05048 望道学者结题报告 课题名称：细菌菌群间的相互作用对表皮葡萄球菌生物膜形成的影响 申 请 人：芮晶 学号：0256365 联系电话：0256365 e-mail: 0256365@fudan.edu.cn 所在院系(专业)：上海医学院临床医学七年2002 导 师：高谦 导师单位(部门)：上海医学院分子病毒实验室 填表日期：2006.5.10 复旦大学教务处制表 细菌菌群间的相互作用对表皮葡萄球菌生物膜形成的影响 摘要：近年来，由表皮葡萄球菌造成的医院感染日趋严重，而生物膜被认为是表皮葡萄球菌致病的主要原因。本实验主要通过与表皮葡萄球菌共存的细菌分泌的种间信号分子AI-2对表皮葡萄球菌生物膜形成的影响来分析这些共存菌对表皮葡萄球菌生物膜形成的影响。方法：1，测试共存菌的无细胞上清对表皮葡萄球菌生物膜形成的影响(半定量—生物膜检测方法)；2，把表皮葡萄球菌的共存菌用AI-2检测系统检测其无细胞上清液中有无AI-2分子。结果：大肠杆菌分泌AI-2，且明显影响表皮葡萄球菌生物膜的形成；金黄色葡萄球菌分泌AI-2，但发光值不高，未发现它明显抑制生物膜的形成；粪肠球菌，绿脓杆菌不分泌AI-2，但能抑制表皮葡萄球菌生物膜的形成。结论：与表皮葡萄球菌共存的细菌对表皮葡萄球菌生物膜形成有影响，这种影响是通过分泌AI-2或其他种间信号分子传递信息的。 关键词：表皮葡萄球菌　生物膜　AI-2 Abstract: Hospital infection caused by Staphylococcus epidermidis becomes more and more serious over the years, and biofilm is thought as the main virulence factor responsible for those infections. This study is objected to investigate the influence of other bacteria living within the same microenviroment with S. epidermidis on its biofilm formation and one of the potential mechanisms is their communication by interspecies’ signaling molecule, autoinducer-2(AI-2). Methods: 1.Testing the effect of cell-free medium (including molecules secreted by the bacteria) from co-existing bacteria with S. epidermidis on its biofilm formation (semi-quantitative biofilm assay); 2. Testing if these co-existing bacteria produce AI-2 molecules (AI-2 report assay). Results: E coli obviously inhibited S. epidermidis’s biofilm formation, and it also secreted AI-2; Staphylococcus aureus has no obvious effect on S. epidermidis’s biofilm formation although it secreted AI-2; Enterococcus faecalis and aeruginosus Bacillus were not detected for AI-2 activity, however, they inhibited S. epidermidis from forming biofilm as well. Conclusion: Some of the bacteria co-exist with S. epidermidis’s exert influence on its biofilm formation, which may depends on AI-2 or other interspecies’ signaling molecules to exchange information. Key words: Staphylococcus epid