RESUMEN
To study the effect of Zataria multiflora essential oil on the clinical isolates of Streptococcus,agalactiae, Staphylococcus,aureus and E. coli isolated from milk of cows with mastitis. Discription study. In this study milk samples from cows affected mastitis were collected from a farm near Tehran. Using microbiological, biochemical and serological methods,bacteria were isolated, identified and serotyped. The MIC of Zataria multiflora essential oil against Streptococcus,agalactiae, Staphylococcus,aureus and Escherichia coli, isolated in this study were evaluated. Sterptococcus agalactiae, Staphylococcus aureus and Escherichia coli were isolated from 6,21 and 5 samplesespectively. All the isolated strains were more resistant to Zataria multiflora essential oil than the standard ones. The MICs of Zataria multiflora on isolated strains of S. aureus and Strep, agalactiae used in this study were 4 and 1.5 timesmore than the corresponding standard strains. According to the results of this study, Zatariamultiflora essential oil had good antibacterial effect on theisolated strains of Streptococcus agalactiae andStaphylococcus aureus