Comparison of antibacterial effect of essential oils of rosemary (Rosmarinus officinalis) and basil (Ocimum basilicum) and some antibiotics on standard isolates of major bovine mastitis bacteria
Subject Areas : Veterinary Clinical PathologyReza Rahchamani 1 , Saman Zaroni 2 , Farzad Ghanbari 3
1 - Assistant Professor, Department of Animal Sciences, Faculty of Agriculture and Natural Resources, University of Gonbad Kavous, Gonbad Kavous, Iran.
2 - M.Sc. Graduate, Department of Animal Sciences, Faculty of Agriculture and Natural Resources, University of Gonbad Kavous, Gonbad Kavous, Iran.
3 - Assistant Professor, Department of Animal Sciences, Faculty of Agriculture and Natural Resources, University of Gonbad Kavous, Gonbad Kavous, Iran.
Keywords: Antibacterial effect, Basil, Essential oil, Mastitis, Rosemary.,
Abstract :
According to the side effects of antibiotic use, there is a need for new and natural antibacterial substances, one of which is the essential oils of medicinal plants. This study investigated antibacterial activity of Rosmarinus officinalis (rosemary) and Ocimum basilicum (basil) EOs in comparison with gentamicin and amoxicillin/clavulanate antibiotics on Escherichia coli, Streptococcus agalactiae, and Staphylococcus aureus. Analysis of EOs was done with GC/MS. The minimum bactericide concentration (MBC) and minimum inhibitory concentration (MIC) were obtained with macrodilution method and the antibacterial effects of EOs in comparison with antibiotics were done by disk diffusion method. The effects of EOs on growth curve were investigated at 0, 6, 10 and 24 h. Major components of rosemary EO were carene (45.11%), eucalyptol (1,8- cineol) (20.62%), and those of basil were estragol (70.42%), carene (17.99%). MIC and MBC were in rosemary 0.078-0.312% and 0.312-0.625% and in basil 0.039-0.312% and 0.078-0.625%, respectively. In disk diffusion, the effect of two EOs on Staphylococcus aureus and Streptococcus agalactiae did not significantly differ from gentamicin (p>0.05) and lower than amoxicillin/clavulanate (p<0.05) but the effect of two EOs on Escherichia coli was significantly lower than gentamicin and amoxicillin/clavulanate (p<0.05). At 24 hour, two EOs significantly decreased the count of Staphylococcus aureus and Escherichia coli bacteria and basil significantly decreased the Streptococcus agalactiae bacterium count (p<0.05). Generally, the EOs of rosemary and basil had antibacterial effects and the effect on Staphylococcus aureus and Streptococcus agalactiae bacteria was not significantly different with gentamicin.
