Evaluation of antibacterial effect of some of the endemic herbal essential oils on Streptococcus iniae in invitro

Streptococcus iniae is the most causative agent of economic losses in fish farms in Iran. In this study, antibacterial effects of the essential oils of Eryngium campestre, Pimpinella affinis, Zataria multiflora Boiss, Bunium persicum and Allium sativum on S. iniae, the causative agent of zoonotic disease was investigated. The disc diffusion method, Minimum Bacteriocidal Concentration (MBC) and determination of minimum inhibitory concentration (MIC) of the essential oils against S. iniae were employed to determination of antibacterial effects of essential oils and streptomycin were used as standard. The MBC of essential of E. campestre, P. affinis, Z. multiflora, B. persicum and A. sativum were 1, >1, 0.25, 0.12 and 0.5 (μg/ml), respectively, MIC of these essential was 0.5, 0.5, 0.06, 0.06 and 0.12 (μg/ml) respectively, and diameter of zone of inhibition were 27.3±1.7, 22.8± 1.1, 32.8 ± 1.3, 17 ± 0.4 and 18.5 ± 0.7 (mm) were, respectively, against S. iniae. Results of the present study demonstrated that the essential oils of B. persicum Z. multiflora and A. sativum were appropriate antifungal agents against S. iniae. As a result of this study using these herbal essential oils were suitable alternative than common antibiotics to treatment infections caused by S. iniae, the causative agent of zoonotic disease.