Evaluation of antimicrobial activity hydro alcoholic extract of some medicinal herbs against a range of Gram-positive and gram-negative bacteria

Bacterial have caused the outbreak of diseases more than any other pathogens that are transmitted by food. The aim of this study is to evaluate the extracts of the medicinal plants, saffron, yarrow, thyme and rosemary on the bacteria Escherichia coli, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. Antimicrobial effects of hydro-ethanol extract on the bacteria was surveyed using diffusion method in a culture medium Mueller-Hinton agar by paper discs (6 mm) based on Bauer and Kirby instructions. The antibiotics ciprofloxacin, amikacin, gentamicin, azithromycin, trimethoprim-sulfamethoxazole, ceftriaxone, penicillin and ampicillin were used as positive control. Means square was conducted by Least Significant Difference (LSD) test at five percent of probability level (P<0.05). Myrtus Extract is the most effective medicinal plant on the bacteria Listeria, Salmonella typhimurium and Staphylococcus aureus, respectively; with an average of 2.5±0.43, 1.67±0.25 and 2.33±0.66 cm the diameter of bacterial inhibition zone. Rosemary Extract is the most effective medicinal plant on the bacteria E.coli, respectively with an average of 1.25±0.66 cm the diameter of bacterial inhibition zone. Comparison of the effect of plant extracts with antibiotics was used in this research, and it was found that most of the extracts were more effective than ampicillin and penicillin on the bacterium E. coli. Myrtus extract, compared with all antibiotics, was more effective on bacteria Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. According to the results and increasing resistance to antimicrobial synthetic materials; Myrtus, and after that, rosemary plant can be as effective in destroying some bacteria like; E.coli, Listeria monocytogenes, Salmonella typhimurium and Staphylococcus aureus.