Antibacterial Activity of Garlic (Allium sativum) Extract Against Escherichia coli and Staphylococcus aureus: An in Vitro Experimental Study

Abstract

As the global prevalence of antimicrobial resistance continues to rise, market demand for alternative antimicrobial agents derived from medicinal plants continues to grow. Garlic, which contains sulfur-based bioactive compounds with confirmed antimicrobial activity, has become a popular subject of research in related fields. This study took Escherichia coli and Staphylococcus aureus as target strains and conducted in vitro antimicrobial experiments using the agar well diffusion method, minimum inhibitory concentration (MIC) assay, and minimum bactericidal concentration (MBC) assay. We prepared aqueous extracts of fresh garlic at four concentration levels: 25%, 50%, 75%, and 100%, and used Mueller–Hinton agar as the culture medium for the tested strains. The results showed that the antimicrobial activity of the extract was concentration-dependent, and Staphylococcus aureus had significantly higher susceptibility to the extract than Escherichia coli (p<0.05). At the 100% extract concentration, the inhibition zone diameter for Staphylococcus aureus was 27.4±0.6 mm, while that for Escherichia coli was 21.8±0.5 mm. The MIC of the extract against Staphylococcus aureus was 12.5 mg/mL, and its MBC against this strain was 25 mg/mL; against Escherichia coli, the extract had an MIC of 25 mg/mL and an MBC of 50 mg/mL. These findings verify the antimicrobial potential of garlic aqueous extract and support its application as a supplementary natural antimicrobial agent.