Evaluation of the antibacterial activity of Zataria multiflora Boiss., Rhus coriaria L. (sumac), Mentha piperita L., and Ocimum basilicum L. extracts on Brucella strains isolated from brucellosis patients

Aim: Since brucellosis has been called a chronic illness and treatment of patients infected with this bacterium has notbeen successful, the present study aimed to evaluate the effects of several medicinal plant extracts on clinical Brucellastrains. Materials and methods: First, Brucella strains were isolated from brucellosis patients. Then an antibiotic resistanceassay was performed for these strains, while the antibacterial activity of the above-mentioned extracts was evaluated. Results: After performing accurate evaluations, the obtained results showed that all of the isolated Brucella strains were sensitive to tetracycline, doxycycline, and gentamicin, and the rates of antibiotic resistance to rifampin and streptomycin were 83.3% and 11.1%, respectively. The mean zone of growth inhibition for Zataria multiflora Boiss. was ≥28.77 mm, Rhus coriaria L. (sumac) was 22.55 mm, Mentha piperita L. was ≥7.5 mm, and the gentamicin disk was ≥30 mm. The mean minimum inhibitory concentration (MIC) for Z. multiflora was 1237 μg/mL, and it was 3255.2 μg/mL for sumac, and 5642 μg/mL for M. piperita L. The minimum bactericidal concentration (MBC) rate for these herbs was 5900 μg/mL, 9027 μg/mL, and 12152 μg/mL, respectively. Furthermore, no anti-Brucella activity was observed for Ocimumbasilicum L.Conclusion: The results obtained in this study prove that Z. multiflora extracts show high anti-Brucella activity and itcan be used for better treatment of brucellosis.