[Antibacterial effects of Rosmarinus officinalis on methicillin - resistant Staphylococcus aureus isolated from patients and foods]

Methicillin-resistant Staphylcoccus aureus [MRSA] is considered a major problem in the world. This strain colonizes nose and causes increased incidence of nosocomial infections, mortality and morbidity. Rosemary [Rosmarinus officinalis] is a herbal medicine widely used all over the world. The aim of this study was to evaluate the in vitro antimicrobial activity of rosemary essence on MRSA isolated from patients and food. 200 strains of MRSA, 100 from patients and 100 from food samples, were collected and analyzed in Tehran, during the last year. 28 MRSA strains and multi drug resistant [MDR] strains were isolated. The antimicrobial activity of the rosemary essence against different isolates of the microorganism was evaluated by disk diffusion and macro broth dilution methods. MRSA isolates belonged to 25% and 60% of food and clinical samples, respectively. The results showed effective and similar antimicrobial activity of Rosmarinus officinalis on broth clinical and food samples with an inhibition zone of 20mm in diameter. The minimum inhibitory concentration [MIC] and minimum bactericidal concentration [MBC] in our study were 1.40 mg/ml and 2.81 mg/ml, respectively. Overuse of antibiotics has led to extensive bacterial resistance to antibiotics, which demonstrates the need for use of new antimicrobial agents. Considering increasing prevalence of MRSA strains and the beneficial effect of rosemary essence on these strains, this essence can be recommended for the treatment of MRSA infections