甲氧苄啶对连翘体外抗菌增效作用的研究

Study on Antibacteria Synergitic Effect of Trimethoprim Combined with Forsythia Suspensa in Vitro

采用微量棋盘法测定甲氧苄啶、连翘及药物联用对金黄色葡萄球菌、大肠杆菌和沙门氏菌的最小抑菌浓度,计算连翘与甲氧苄啶联用的FIC指数。再采用平板计数法测定连翘与甲氧苄啶联合作用于三种细菌1、2、4和8 h后的细菌数,并计算杀菌率。利用最小二乘法对杀菌率进行拟合,计算出甲氧苄啶与连翘配伍的最佳添加剂量。试验结果表明:连翘与甲氧苄啶联用对金黄色葡萄球菌和大肠杆菌的FIC指数为0.5,呈协同作用;对沙门氏菌的FIC指数为0.75,呈相加作用。甲氧苄啶与连翘体外抗菌最佳配伍剂量为7.2 mg.g-1。

The minimum inhibitory concentrations（MIC） of forsythia suspensa,trimethoprim（TMP） and forsythia suspense combined with TMP were measured individually by the method of microdilution checkerboard techniques against Staphylococcus aureus,Escherichia Coli and Salmonella.The fractional inhibitory concentrations（FIC） indices were calculated on forsythia suspensa combined with TMP.The number of Staphylococcus aureus,Escherichia Coli and Salmonella were enumerated by plate counts methods,which had been inhabited by forsythia suspensa combined with TMP for 1,2,4 and 8 h.The bactericidal rate of forsythia suspensa combined with TMP was calculated.The experimental data were fitted by least squares method,and the optimal dose of compatibility was determined on TMP combined with forsythia suspensa.The results showed that the FIC values on Staphylococcus aureus and Escherichia Coli were 0.5,0.5 respectively.The effect of drugs combination showed synergistic action.The FIC value on Salmonella was equal to 0.75.The effect of drugs combination was taken on additive action.The optimal dose of compatibility were 7.2 mg·g-1 on TMP combined with forsythia suspensa in vitro.