克拉霉素与头孢呋辛联合应用对肺炎链球菌和金黄色葡萄球菌的体内抗生素后效应

目的：探讨克拉霉素（CLA）与头孢呋辛（CEFU）联合应用对肺炎链球菌和金黄色葡萄球菌的体内抗生素后效应（PAE）。方法：采用琼脂平板倍比稀释法和棋盘法分别测定CLA、CEFU单用及联用时对肺炎链球菌、金黄色葡萄球菌的最小抑菌浓度（MIC），并计算联合指数（FIC）；建立小鼠股部肺炎链球菌、金黄色葡萄球菌感染模型，并且应用平板菌落计数法测定CLA与CEFU单用及联合应用对肺炎链球菌、金黄色葡萄球菌的体内PAE。结果：CLA、CEFU单用及联用均对肺炎链球菌、金黄色葡萄球菌产生一定的PAE；两者联用的PAE长于单用时的PAE，呈浓度依赖性，联用后对肺炎链球菌体内PAE表现为相加或无关作用，对金黄色葡萄球菌体内PAE表现为无关作用。结论：CLA与CEFU联用能延长CLA、CEFU单用时的PAE。

Postantibiotic effect of combined clarithromycin and cefuroxime sodium against Streptococcus pneumoniae and Staphylococcus aureus in vivo

OBJECTIVE To explore the postantibiotic effect of combined clarithromycin (CLA) and cefuroxime sodium (CEFU) against Streptococcus pneumoniae and Staphylococcus aureus in vivo.METHODS Minimum inhibitory concentrations (MIC) of CLA and CEFU used alone were determined using agar plates dilution method,and the combined MIC was obtained by using the Chess board method.The fractional inhibitory concentration index (FIC) was subsequently calculated.An infection model of neutropenic mouse thigh with Streptococcus pneumonia and Staphylococcus aureus was established.The post antibiotic effects (PAE) of CLA and CEFU used separately and jointly against Streptococcus pneumoniae and Staphylococcus aureus in vivo were determined by plate colony counting.RESULTS The CLA and CEFU used separately and jointly produced definite PAE against Streptococcus pneumoniae and Staphylococcus aureus in vivo.Moreover,the effect was quite dependent on the drug concentration.The PAE from the combined medication lasted longer than that from the single drug,besides the combined medication had additional effect or indifferent effect on PAE against Streptococcus pneumonia. Combined medication had no effect on PAE against Staphylococcus aureus.CONCLUSION The combined CLA and CEFU can prolong the time of PAE against Streptococcus pneumonia and Staphylococcus aureus compared with single drug.