Effect of Essential Oils of Salvia officinalis and Satureja hortensis on Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli

There is need to investigate new and natural antibacterial agents because of various side effects of antibiotics. Essential oil of medicinal plants is one of these agents. The aim of this study was to determine the antibacterial activity of Salvia officinalis (sage) and Satureja hortensis (savory) essential oils in comparison with Gentamicin and Amoxicillin / Clavulanate antibiotics on Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli. Chemical compositions of essential oils were determined by GC/MS. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) of oils and the inhibition zones of oils and antibiotics were determined using serial broth dilution and disk diffusion method, respectively. The effect of MIC concentrations of oils on growth curve of bacteria were obtained at 0, 6, 10 and 24 hour. Major compositions of sage and savory oils were carvacrol (61.01%), thymol (20.41%) and eucalyptol (32.45%), thymol (28.24%), respectively. According to MIC and MBC results, the most antibacterial activity of sage was against Staphylococcus aureus (0.009% and 0.019%, respectively) and those of savory were against Streptococcus agalactiae (0.078%, 0.156%, respectively). The inhibition zone of oils had no significant difference with antibiotics and antibacterial effect of sage was more than savory. MIC concentrations of oils decreased bacterial count at 24 h. Generally, the essential oil of sage had a stronger antibacterial effect than savory because of more strong antibacterial components (carvacrol and thymol) and Antibacterial effects of two oils had no significant difference with gentamycin and amoxicillin/ clavulanate that show satisfactory antibacterial effect of oils.