Ciprofloxacin Combined with Amikacin to Reduce Drug-resistant Mutants of Escherichia coli / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To study whether the ciprofloxacin(CIP)combined with amikacin(AMK)will decrease the drug-resistant mutants of Escherichia coli(ECO)in vitro.METHODS The MIC of CIP and AMK alone was determined by agar plates dilution method,and the combined MIC by checkerboard method.The mutant prevention concentration(MPC)both alone and combined was determined by the method of agar plates dilution method,and then the value of selectiveity index(SI)(MPC/MIC)would be acquired.RESULTS The SI of two antibiotics separatedly were 16(CIP)and 32(AMK).When two antibiotics combined,if the concentration of AMK and CIP reached 2MIC could restrain the mutants.After these two antibiotics combined,the value of SI(MPCcombined/MICcombined)came to be 8(0.008/0.001)and 8(2.0/0.25).CONCLUSIONS Compared with alone,CIP and AMK combined can decrease the MPC and SI to ECO,and have the more effect to AMK.In this way,we can reduce the drug-resistant mutants.