Antibacterial Effect of Allium sativum L. and Allium cepa L. Extracts against Multidrug-Resistant Escherichia coli Strains Isolated from Broiler Chickens

Over the past decades, the incidence of avian colibacillosis caused by multidrug-resistant Escherichia coli (E. coli) has increased dramatically worldwide. The present in vitro study focused on evaluating the antibacterial properties of Allium sativum L. and Allium cepa L. extracts against multidrug-resistant E. coli strains isolated from broiler chickens suffering from colibacillosis. The confirmation of E. coli isolates and their antibiotic resistance was performed using conventional methods. Furthermore, the antimicrobial activity of both extracts was assessed through the disk diffusion method, along with the determination of the minimum inhibitory concentration (MIC) via liquid macrodilution and the minimum bactericidal concentration (MBC) using solid media. The obtained results showed that the multidrug-resistant E. coli strains were extremely sensitive to garlic extract with a MIC of 41.5 mg / mL and CMB of 166 mg / mL and very sensitive to the combination of garlic and onion extracts. However, onion extract was ineffective against the resistant E. coli strains. The findings of the present study suggested the possibility of using garlic as an alternative to antibiotics in the treatment of colibacillosis caused by resistant E. coli strains.