SUSCEPTIBILITY PATTERNS OF SOME POTENTIALLY PATHOGENIC BACTERIA TO EXTRACTS OF ALLIUM SATIVUM (GARLIC)

This study evaluated the antibacterial activity of aqueous and ethanolic extracts of Allium sativum (garlic) against two clinical bacterial isolates, Staphylococcus aureus and Escherichia coli. Extracts were prepared using cold maceration, and their antibacterial activity was determined using the agar well diffusion method at concentrations ranging from 25 to 200 mg/mL. Ciprofloxacin served as the positive control, while sterile distilled water was used as the negative control. The ethanolic extract exhibited significantly higher antibacterial activity than the aqueous extract, producing inhibition zones up to 40.0 ± 0.0 mm against S. aureus and 36.7 ± 2.9 mm against E. coli at 200 mg/mL. In contrast, the aqueous extract produced maximum inhibition zones of 21.7 ± 2.9 mm and 18.3 ± 2.9 mm against S. aureus and E. coli, respectively. The minimum inhibitory concentration (MIC) of the ethanolic extract was 100 mg/mL for S. aureus and E. coli, while the aqueous extract required 200 mg/mL for both organisms. No minimum bactericidal concentration (MBC) was detected, indicating a bacteriostatic rather than bactericidal effect. Statistical analysis confirmed significant differences in antibacterial activity between solvent types and concentrations (p < 0.05). These findings highlight the potential of garlic, especially ethanol- based extracts, as a natural antibacterial agent with applications in managing bacterial infections. Further studies on bioactive compound isolation and in vivo validation are recommended.