Evaluation of the Antimicrobial Activity of Olive and Rosemary Leave Extracts Prepared with Different Solvents Against Antibiotic-Resistant Escherichia coli

Background: This study was done to investigate the antimicrobial activity of rosemary and olive extracts on antibiotic-resistant Escherichia coli isolated from quail feces in Zabol city. Methods: Ethanolic and methanolic extracts of rosemary (leaf) and olive (leaf) plants were prepared using a rotary apparatus. Also, E. coli strains were isolated from poultry feces samples, the minimum inhibitory concentration and the minimum bactericidal concentration were determined by the microdilution method. Results: The lowest values of MIC and MBC against E. coli were 12.5 ppm and 25 ppm for rosemary ethanolic extract and 25 ppm and 50 ppm for rosemary methanolic extract, respectively. The lowest values of MIC and MBC against E. coli were 12.5 ppm and 25 ppm for olive ethanolic extract and 6.25 ppm and 12.5 ppm for olive methanolic extract, respectively. Conclusions: In general, methanol solvent and olive extract are highly effective against E. coli. Due to the obtained results and increasing resistance of bacteria to chemical antibiotics, it is suggested that with further studies on olives and the use of methanol solvent in the extraction of plant extracts, antibacterial compounds of olives and other plants be used in the treatment of bacterial infections.