Comparison of Disk Diffusion and E-Test Methods to Determine Antimicrobial Activity of Ceftazidime and Ciprofloxacin on Clinical Isolates of Acinetobacter baumannii

This study is aimed to find a specific method to test the clinical isolates of Acintobacter Baumanniiin terms of antimicrobial susceptibility and resistance to two drugs of Ceftazidime and Ciprofloxacin using E-test and Disk Diffusion methods. Totally 100 samples were collected from hospitalized patients at the general hospitals of Kerman Province, Southeastern, Iran between November 2013 to April 2014. They were identified by standard microbiological methods. Susceptibility by Disk diffusion and MIC by E-test were performed according to the Clinical and Laboratory Standards Institute breakpoints. In the disk diffusion method for ciprofloxacin antibiotic, the Acinetobacter specimens were reported to be 85% resistant, 4% intermediate, and only 11% susceptible. Also, for Ceftazidime antibiotic, the specimens were reported as 75% resistant, 15% intermediate, and only 10% susceptible. In the E-test method for ciprofloxacin antibiotic, the Acinetobacter specimens were reported to be 95% resistant, 0% intermediate, and 5% susceptible. Also, for Ceftazidime, the specimens were reported to be 93% resistant, 4% intermediate, and 3% susceptible. After performing the statistical Chi square test at confidence level of 95%, the P value for these two antibiotics was obtained (p<0.199) in both methods. The findings of present study revealed the high resistance of this bacterium in Kerman Province and feeling the necessity of thinking of some strategies and solutions for reducing that microbial resistance as well as paying more attention to the selective treatments, antibiotic treatment course duration, and other instances that should be taken into account in any antibiotic diet in order to prevent and avoid such high levels of microbial resistance in our country.

Key words: Acintobacter; antibiotic; resistance; disk diffusion; T-test

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