Antibacterial effects of aqueous and alcoholic extracts of Thyme on enterohemorrhagic Escherichia coli

Background: Because of increasing resistance to current antibiotics, many attempts have been made by the researchers to find new compounds of plant derivatives as substitute for non-effective antibiotics. This research was performed to study the antibacterial properties of aquatic and alcoholic extracts of thyme on the clinical and standard strains of enterohemorrhagic Escherichia coli. Material and methods: After drying, the thyme leaves were added to ethanol 85º and distilled water separately. Then the compounds of plant were extracted by distillation method. The antibacterial properties of extracts were investigated by tube dilution method in broth media. By using different concentrations of the extracts, MIC & MBC were determined and equal amounts of these concentrations were added to excavated wells in Mueller – Hinton agar. Then the mean diameter of growth inhibition zones for extracts and strains were compared. Results: Certain concentrations of the alcoholic extract showed significant antibacterial effect. Alcoholic extract with 0.780mg/ml showed growth inhibitory effect and bactericidal effect on strains, whereas the aquatic extract didn’t show any effect on the given strains. Conclusion: Some of the concentrations of the alcoholic extract showed pronounced antibacterial activity on the strains of enterohemorrhagic Escherichia coli but it is necessary to do more studies on its antibacterial effects.