Based on the importance of herbal plants in medicine, this study was conducted to evaluate the antibacterial efficacy of aqueous, ethanol and methanol extracts of Thymbra spicata, Nepeta curviflora, and Verbascum fruticulosum against two clinical isolates (I and II) of the gram positive methicillin resistant Staphylococcus aureus (MRSA). Agar well diffusion method was performed to examine the antibacterial activity of all studied plant extracts. Micro-broth dilution method was used to measure the minimum inhibitory concentration (MIC) then the minimum bacteriocidal concentration (MBC) for all active extracts. The examined isolates were susceptible to the prepared plant extracts. Ethanol and methanol extracts of T. spicata were the most efficient extracts. Ethanol and methanol extracts for all plants in this study showed higher antibacterial activity compared to aqueous extracts. Among the studied plant extracts, T. spicata extracts showed the best antibacterial effect for MRSA as they act as bacteriocidal agents at concentration range (0.781-6.25) mg/ml. Fractionation and characterization of T. spicata active components may enhance the pharmaceutical industry of new drugs against MRSA.
Keywords: Antibacterial, Methicillin Resistant Staphylococcus aureus, Thymbra spicata, Nepeta curviflora, Verbascum fruticulosum.