No abstract

In this study the essential oil of Thymus kotschyanus Boiss. & Hohen, which is endemic of Iran, was investigated for its antibacterial activity and its combined effects with oxacillin or methicillin against several clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations of oxacillin, methicillin and essential oil against MRSA strains were determined by the microdilution method. Synergy testing of each antibiotic and essential oil against MRSA was performed by the checkerboard technique. The results indicated that T. kotschyanus essential oil had synergistic effect with oxacillin or methicillin against MRSA strains. The best synergistic effect obtained against MRSA5 and S. aureus ATCC 33591 which resulted in 32 times decrease in MIC values of oxacillin and methicillin. The synergistic activity showed that this non-antibiotic agent manifests a broad spectrum of activity against MRSA bacteria which might open a new therapeutic approach to combat drug-resistance in bacterial infections.