藤茶双氢杨梅树皮素协同β-内酰胺类抗生素抗MRSA生物被膜的作用机制研究

MRSA在临床的耐药情况日益严重，其耐药机制除了生成β-内酰胺酶和生成新的PBP2a外，目前生物被膜的形成被认为是其耐药尤其是多重耐药的机制之一。我们前期研究发现，广西藤茶提取物双氢杨梅树皮素（APS）与β－内酰胺类抗菌药物合用后可在体外、体内发挥协同抗MRSA作用。由此我们推测APS对MRSA生物被膜形成的环节可能具有一定干预作用。本课题拟以96孔板建立MRSA生物被膜体外模型，采用MTT法、激光共聚焦显微镜法及实时荧光定量RT-PCR等方法，从MRSA生物被膜形态变化、形成关键基因的表达水平等方面观察药物对MRSA生物被膜的作用；构建MRSA生物被膜肺部感染树鼩模型，从肺部定殖细菌数、病理学形态变化及炎症细胞因子变化水平等方面研究药物对MRSA生物被膜体内抗感染的作用，力图从本质上阐明APS协同β-内酰胺类抗菌药物抑制MRSA生物被膜、逆转MRSA的耐药机制，为其联合用药提供理论依据。

The resistance of Methicillin-resistant Staphylococcus aureus(MRSA)is in critical condition which the mechanism involving β－lactamase and a new protein PBP2a. Currently, the formation of bacterial biofilm is considered as one of the multi-resistance mechanism. We have found that Ampelopsin(APS)which extracted from Ampelopsis grossedentata(Hand-Mazz) in Guangxi showed the synergistic effects against MRSA when combinating with β－lactam antibiotics in vitro and in vivo. We speculate that the drug may has intervention in the formation of MRSA biofilm.We are trying to survey the anti-biofilm effect from the variation of biofilm morphology and key genes with argentation, MTT, CLSM and Real time fluorescence quantitative RT-PCR in vitro. MRSA biofilm lung infection tree shrew model was established to evaluate the anti-infective effect on the bacterial number in lung, Pathological morphology and the levels of inflammatory cytokines. The project aims to clarify essentially the anti-biofilm mechanism of the combination of APS and β－lactam antibiotics, and to provide a basis for the rationality of APS combination with β－lactam antibiotics.