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目的观察亚抑菌浓度(亚-MIC)穿心莲内酯及其与红霉素联用对表皮葡萄球菌生物膜形成的影响。方法连续稀释法测定穿心莲内酯和红霉素对表皮葡萄球菌的MIC;棋盘格法测定穿心莲内酯和红霉素联用对表皮葡萄球菌悬浮菌的作用;体外构建表皮葡萄球菌生物膜,XTT减低法评价亚-MIC穿心莲内酯及与红霉素联用对表皮葡萄球菌生物膜内细菌代谢及初始黏附能力的影响,扫描电镜观察用药后表皮葡萄球菌形态和生物膜结构改变。结果穿心莲内酯对表皮葡萄球菌悬浮菌的MIC大于1000 mg/L,穿心莲内酯和红霉素联用对表皮葡萄球菌悬浮菌的FIC指数(联合抑菌分数)>2;亚抑菌浓度穿心莲内酯对表皮葡萄球菌生物膜黏附及膜内菌代谢均有抑制作用;穿心莲内酯和红霉素联用对表皮葡萄球菌的黏附能力的影响表现为协同作用,对悬浮菌和膜内菌代谢作用表现为拮抗。结论亚抑菌浓度穿心莲内酯对表皮葡萄球菌生物膜黏附及膜内菌代谢均有抑制作用;穿心莲内酯和红霉素联用对表皮葡萄球菌悬浮菌及膜内菌代谢存在拮抗,提示临床治疗表皮葡萄球菌感染时应避免同时使用这两种药物。
Objective To observe the effect of sub-inhibitory concentration (sub-MIC) of andrographolide on the biofilm formation of Staphylococcus epidermidis in combination with erythromycin. Methods The MICs of andrographolide and erythromycin against Staphylococcus epidermidis were determined by serial dilution method. The effects of andrographolide and erythromycin on the suspension of Staphylococcus epidermidis were determined by the checkerboard method. Staphylococcus epidermidis biofilms were constructed by XTT The effects of sub-MIC of andrographolide and erythromycin on the bacterial metabolism and initial adhesion capacity of Staphylococcus epidermidis biofilms were also evaluated by SEM. The morphology and biofilm structure of Staphylococcus epidermidis were observed by scanning electron microscopy. Results The MICs of andrographolide against Staphylococcus epidermidis were more than 1000 mg / L, the FIC index (combined antibacterial fraction) of the combination of andrographolide and erythromycin against Staphylococcus epidermidis was> 2, the concentration of andrographolide Lactone on Staphylococcus epidermidis biofilm adhesion and membrane metabolism were inhibited; andrographolide and erythromycin combined effect on the adhesion of Staphylococcus epidermidis showed synergistic effect on the suspension bacteria and membrane metabolism The role of performance as antagonistic. Conclusion Andrographolide can inhibit the adherence of Staphylococcus epidermidis to biofilm and the metabolism of bacteria in the membrane. The combination of andrographolide and erythromycin antagonizes the metabolism of Staphylococcus epidermidis and bacteria, suggesting that the clinical Staphylococcus epidermidis infection should avoid the simultaneous use of these two drugs.