中文摘要：

目的评价米诺环素（四环素类半合成抗菌药）和利福平（抗结核药）对临床分离到的100株耐甲氧西林金黄色葡萄球菌（MRSA）的联合体外抗菌活性。方法采用棋盘法设计，用微量肉汤稀释法测定不同浓度组合的抗菌药物对100株MRSA最低抑菌浓度，计算部分抑菌浓度指数（FICI），判定联合效应。结果2种抗菌药物联用后，对100株MRSA的MIC。显著降低，FICI分布：FICI≤0．5占92％；0．5〈FICI≤4占8％；FICI〉4为0。结论米诺环素与利福平联用对100株MRSA体外抗菌效应表现为以协同作用为主；无关作用较少，无拮抗作用。

英文摘要：

Objective To investigate the in vitro activity of minocycline combined with rifampin against 100 methicillin -resistant Staphylococcus aureus（MRSA） isolated from two China hospitals＇ clinical specimens of human infections. Methods The checkerboard method and broth microdilution method was used to determine the combinations activity against these strains. The susceptibility results for minocycline and rifampin were interpreted according to the guidelines of the CLSI, fractional inhibitory concentration was used to determine combination effection. Results The MIC50 was reduced significantly for the combination of minocycline and rifampin against MRSA compare to use minocycline and rifampin alone. The results of combination of minocycline and rifampin were 92% （92/100） synergism ; 8% （ 8/100 ） indifference （ minimum and maximum fractional inhibitory concentration index 0. 13 and 0. 53, respectively）, and no antagonism. Conclusion Combinations of minocycline and rifampin may show synergism for most MRSA, and there was on antagonism, which may be a future therapeutic alternative for infections caused by MRSA.