The effect of efflux pump inhibitor on MIC values of nalidixic acit, flouroquinolones and macrolide of multidrug-resistant Escherichia coli

Abstract number: 1733_1569

Tezer Y., Filik I.T., Memikoglu O., Kurt H.

Objective: Efflux pumps are found in all living cells and drop toxic substances and antibiotics from inside to out. As a result, pump system is responsible for multidrug resistance. So we aimed to investigte the effect of this system on some antibiotics minimal inhibitor concentration (MIC) values.

Methods: In this study, we investigated phenyl-arginin-beta-napthylamide (PA-beta-N) effect as an efflux pump inhibitor on multidrug resistant Escherichia coli. For this study during 6 months periods, 100 clinical isolates which were multiple drug resistant pattern that had been determined via disc diffusion methods collected. With agar dilution method, MIC values of four antibiotics which were nalidixic acit, ciprofloxacin, levofloxacin, and erytromycin were determined.

After that, having efflux pump had been searched by organic solvent tolerance test. Then we examined nalidixic acit, flouroquinolones and macrolide MIC values via broth dilution method with PA-beta-N and without it.

After broth dilution method, different concentrations of PA-beta-N were studied in tolerant isolates. Results were analysed with Mann-Whitney U tests.

Results: Fifty five percent of isolates were tolerant to organic solvents. It means that, efflux pump was overexpressed in these isolates. For levofloxacin and erytromycin MIC values were decreased with PA-beta-N. On the other hand there were no change on ciprofloxacin and nalidixic acit MIC values. For ciprofloxacin and nalididixic acit there were no significant statistical value on MIC values. But on the other hand for levofloxacin and erytromycin there were significant statistical change on MIC values.

In addition PA-beta-N has homogenous effect in different concentrations and no concentration dependent effect was determined.

Conclusions: Effect of efflux pump on multidrug resistance mechanisms was rarely reported from our country and all over the world. So we thought that studies that made by specific inhibitors of efflux pump, like using b-lactam/b-lactamases might be innovator in clinical applications.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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