Effects of Nigella sativa L.’s Essential Oils on Multi Drug Resistant Escherichia coli Isolates

Escherichia coli is one of the most important human pathogens and is a major cause of nosocomial infections. In this study, it was aimed to investigate the antimicrobial efficacy of Nigella sativa L. against multi drug-resistant E. coli isolates. This study was carried out on multi drug resistant E. coli isolates. In this study, seeds of Nigella sativa L. obtained from spice market were used as material .Multidrug resistant E. coli strains were identified by conventional methods. The antibacterial activity of Nigella sativa L.'s essential oils was performed by disk diffusion test. In addition, when needed, automated systems were used for rapid identification of microorganisms and susceptibility testing identification. The ESBL production of these strains was confirmed by double disc synergy test.In ESBL producing E.coli strains, the MIC range of ampicillin was 4-32 μg/ml and the MIC range of cefuroxime was found to be 2-16 μg/ml. MIC values of ampicillin were range from 0.25 to 4 μg/ml and MIC of levofloxacin range were 1 to 8 μg/ml and MIC of cefuroxime range were found to be 0.25-4 μg/ml. Following treatment with essential oils of Nigella sativa, resistance rates of GSBL producing E.coli strains against all these three antibiotics (ampicillin, levofloxacin and cefuroxime) have been found to decrease statistically significantly (p < 0.05). Nigella sativa L.'s essential oils showed complete zone of inhibition of the standart E.coli strains (p < 0.05).Besides this, in experiments with multi drug resistant E.coli isolates, it was found that the inhibition zones of Nigella-treated GSBL producing E.coli strains differed from non-treated strains. There was a statistically significant increasing in inhibition zones in drug E.coli isolates (p < 0.01).The essential oils of Nigella sativa L. may contain promising antimicrobial components in the treatment of multi drug-resistant Ecoli isolates.This is very important for the discovery of new antimicrobial agents. More extensive clinical trials should be undertaken in this regard.