Antibacterial Activity of iAllium/ii /iiSativum/i, Ziingiber/ii /iiOfficinale/i and Their Synergistic Effect Against iStaphylococcus/ii /iiAureus/i and iEscherichia/ii /iiColi/i Isolated from Milk Samples of a Dairy Farm in Jimma Town Southwestern Ethiopia

The development of antibiotic resistance has recently increased research attention in exploring novel antimicrobial agents sourced from medicinal plants. In Ethiopia,i Allium sativum/ii /i(garlic) and iZingiber officinale/ii /i(ginger) are the most valued medicinal plants. This study investigates the antibacterial properties of extracts obtained from the bulbs and roots ofi Allium Sativum/i, Ziingiber Officinale/i and their synergistic effects against iStaphylococcus/ii Aureus/i and iEscherichia Coli/i strains isolated from milk samples. A 50g powdered bulbs of iA. sativum /iand roots of iZ. officinale/i were separately macerated with 500 mL of distilled water and 95% ethanol in sterilized flasks. The antibacterial effects of crude aqueous and hydro-ethanol extracts of the both plants and their synergistic effects with 95% ethanol extracts were assessed using disc diffusion method, with concentrations of 50, 75 and 100 mg/mL for susceptibility testing. The 95% ethanol extracts of both plants had lowest yield percentage as compared to aqueous extracts. ANOVA was used for statistical analysis, with a significance level of iP/i 0.05. Both 95% ethanol as well as distilled water extracts and their synergistic effects with 95% ethanol extracts exhibited antibacterial activity against iS./ii Aureus/i and iE. Coli/i using iciprofloxacin/i discs as positive and blank discs as a negative control. Among the extracts, the lowest susceptibility was observed for aqueous extracts with inhibition zone of iZ. officinale/i at 50 mg/mL against both bacteria, while iE. coli/i showed a notable susceptibility to iZ. officinale/i at 100 mg/mL. The 95% ethanol extract of iA. sativum/i and its combination showed smaller inhibition zone against both bacteriai /iat 50 mg/mL while, larger inhibition zone was seen with iA. sativum/i against iE./ii coli/i (27.67±0.58 mm) but iZ. officinale /ishowed larger inhibitory zone against iS. aureus/i (19.33±1.15 mm) at concentration of 100 mg/mL compared to water extract. In both aqueous and 95% ethanol extracts, there was statistically a significant difference (iP/i≤0.000) in the susceptibility of all tested bacteria. This study indicate that the extracts obtained from of the bulbs of iA. sativum/i and the roots of iZ. officinale/i have promising antibacterial properties, validating their traditional medicinal use for treating infections.