Abstract:

To study whether the combinations of two drugs of ciprofloxacinamikacin(CIP), ciprofloxacinceftazidime(AMK) and ceftazidimeamikacin(CAZ) will decrease drugresistant mutants of Pseudomonas aeruginosa in vitro. MethodsMinimum inhibitory concentration (MIC) of CIP,AMK, and CAZ alone was determined by an agar plates dilution method and MIC of the combinations of  them was determined by a checkerboard method. Mutant prevention concentration (MPC) of each single and of combinations were determined by the agar plates dilution method, and then the value of SI(MPC/MIC) was obtained.  Capacity in preventing the appearance of drugresistant mutants was determined based on degree that SI dropped. ResultsSI of CIP, AMk, and CAZ was 16, 16, and ＞32, and of ciprofloxacinamikacin(CIP8; AMK4); ciprofloxacinceftazidime(CIP4; CAZ8); ceftazidimeamikacin(AMK8; CAZ4). ConclusionCompared with each one alone, two drug combinations can decrease MPC and SI to pseudomonas aeruginosa and restrain the drugresistant mutants.

Key words: Drug therapy, combination； Pseudomonas aeruginosa; M utant prevention concentration