Post Antibiotic Effect of Netilmicin Combined with Ceftazidime

Objective To study the post antibiotic effect(PAE) of netilmicin combined with ceftazidime. Methods Staphylococcus aureus,Escherichia coti and Pseudomonas aeruginosa were used as target microorganisms.The minimal inhibitory concentration(MIC) of the drugs was determined with the microdilution method while the PAE was measured with the tessellaled design and colony counting method. Results Netilmicin combined with ceftazidine was shown to have stronger PAE on Staphylococcus aureus and Escherichia coli than that on Pseudomonas aeruginosa and the PAE of either drug used alone or both drugs used together was concentration dependent.Combined application of the 2 drugs was shown to exert a striking synergetic PAE on Staphylococcus aureus and Escherichia coli but only an additive effect on Pseudomonas aeruginosa. Conclusion Netilmicin combined with ceftazidime was shown to enhance the PAE on the bacteria used.Combined use of both drug is superior to the use of either drug alone.