Abstract:

Objective To investigate the effect of different concentrations of ethylenediaminetetraacetic acid（EDTA） on the recovery of drug susceptibility of multidrug-resistant extended-spectrum beta-lactamase（ESBL）-producing Escherichia coli. Methods Totally,240 isolates of ESBL-producing Escherichia coli were collected. The minimum inhibitory concentrations（MIC） before and after adding EDTA with low（0.5 mg/mL）,standard（1.0 mg/mL） and high（2.0 mg/mL） concentrations were determined. Results Among the isolates of ESBL-producing Escherichia coli,the difference between the MIC of pure antibiotics and the MIC of antibiotics with EDTA was obvious. The changes of MIC of cefoperazone,ofloxacin and cefepime were the most obvious,followed by amikacin,tobramycin and gentamicin. The change of MIC of aztreonam was small,and the MIC of cefotaxime did not change. In the 3 groups of combination of EDTA and antibiotics at different concentrations,the changes in the MIC of antibiotics were more significant when the antibiotics were combined with the standard concentration and the high concentration of EDTA than when the antibiotics were combined with the low concentration of EDTA,but there was no statistical significance between the standard concentration and the high concentration of EDTA. The MIC of cefotaxime did not change in the 3 groups. Conclusions EDTA of different concentrations has synergistic antibacterial effect on most determined isolates,and it can improve the drug susceptibility of antimicrobial agents,which has important clinical significance.

Key words: Ethylenediaminetetraacetic acid, Extended-spectrum beta-lactamase, Multidrug-resistant Escherichia coli, Drug susceptibility, Restore