Editor: Willem van Eden
Antibacterial effect of oregano essential oil alone and in combination with antibiotics against extended-spectrum β-lactamase-producing Escherichia coli
Article first published online: 28 JUN 2008
© 2008 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
FEMS Immunology & Medical Microbiology
Volume 53, Issue 2, pages 190–194, July 2008
How to Cite
Si, H., Hu, J., Liu, Z. and Zeng, Z.-l. (2008), Antibacterial effect of oregano essential oil alone and in combination with antibiotics against extended-spectrum β-lactamase-producing Escherichia coli. FEMS Immunology & Medical Microbiology, 53: 190–194. doi: 10.1111/j.1574-695X.2008.00414.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Received 26 November 2007; revised 24 February 2008; accepted 25 February 2008.First published online 24 April 2008.
- oregano essential oil;
In this paper, we studied the antibacterial effects of oregano essential oil (OEO) both alone, using a twofold dilution method, and combined with antibiotics, using a checkerboard microtitre assay, against extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. The result indicated that multiple drug-resistant E. coli was very sensitive to OEO and polymycin; their minimal inhibitory concentration values are 0.5 μL mL−1 and 0.8 μg mL−1. The antibacterial effects of OEO in combination with kanamycin were independent against E. coli, with fractional inhibitory concentration (FIC) indices of 1.5. The antibacterial effects of OEO combined with amoxicillin, polymycin, and lincomycin showed an additive effect against E. coli, with FIC indices in the range of 0.625–0.750. The antibacterial effects of OEO in combination with fluoroquinolones, doxycycline, lincomycin, and maquindox florfenicol displayed synergism against E. coli, with FIC indices ranging from 0.375 to 0.500. The combination of OEO with fluoroquinolones, doxycycline, lincomycin, and maquindox florfenicol to treat infections caused by ESBL-producing E. coli may lower, to a great extent, the effective dose of these antibiotics and thus minimize the side effects of antibiotics. This is the first report on OEO against ESBL-producing E. coli.