The anti-bacterial effects of Zataria multiflora extract on common pathogenic Gram positive cocci, pathogenic Gram negative bacilli and non -pathogenic bacteria

Due to increased bacterial resistance to common antibiotics, tendency towards using herbal extracts like Zataria multiflora from Lamiaceae family is increasing. In this study, antibacterial effects of Z. multiflora on several common pathogenic and non pathogenic bacteria were evaluated. Several clinical Gram positive cocci and Gram negative bacilli isolated from patients and healthy humans were identified with standard methods. The extract of Z. multiflora was prepared from dried leaves with maceration method. The antibacterial activity of Zataria extract with initial concentration of 200 µg/ml was determined by micro dilution method. Results obtained showed that the minimum inhibitory concentration varied from 2 to 32 μg/ml for all Gram positive cocci and Gram negative rods while it was 512 μg/ml for Pseudomonas aeroginosa and Shewanella putrifaciance. The minimum bactericidal concentration varied from 4 to 512 μg/ml for examined bacteria. In conclusion, it seems that Zataria extract could inhibit the growth of some clinical Gram positive and Gram negative bacteria. However, the inhibitory effects ofZataria extract for Pseudomonas aeroginsa and Shewanella putrifacians are lower than its inhibitory effects for other Gram negative bacilli in the examined extract concentrations. We noticed that the bactericidal effect of Zataria extract was less than its bacteriostatic effect.    Key words: Ethanolic, Zataria multiflora extract, antibacterial effect, pathogenic bacteria.