Evaluation of the Efficiency of Three Types of <i>Ocimum basilicum</i> and <i>Mentha spicata</i> Leaf Extracts on Some Antibiotic-Resistant Bacteria Isolated from Food

Abstract The current study aimed to evaluate the effectiveness of Ocimum basilicum (basil) and Mentha spicata (mint) leaf extracts in inhibiting the growth of antibiotic-resistant bacteria isolated from food, to detect the active compounds in the plant extracts that give the highest antibacterial activity using high-performance liquid chromatography (HPLC), and to determine the cellular effects of the effective extracts against bacterial isolates using scanning electron microscopy (SEM). Extraction was performed using three solvents: distilled water, 80% ethanol, and ethyl acetate. The effectiveness of these extracts was evaluated by determining the minimum inhibitory concentration (MIC) using the half-dilution method at concentrations (20, 10, 5, 2.5, 1.25, 0.6, 0.3 μg/mL) against ten bacterial species, six of which were gram-negative ( Escherichia coli, Enterobacter cloacae, Pseudomonas sp., Klebsiella sp., Salmonella sp., Shigella sp. ) and four gram-positive ( Staphylococcus aureus, Staphylococcus gallinarum, Staphylococcus xylosus, Staphylococcus saprophyticus ).The MIC results showed that 80% ethanolic extracts of basil and mint had antibacterial activity, with MIC values ranging between 0.3 and 5 μg/mL depending on the bacterial isolate. The cellular effects caused by ethanol and ethyl acetate extracts of basil on Shigella sp. and the effects of ethanol and ethyl acetate extracts of mint on Staphylococcus aureus were studied using scanning electron microscopy (SEM) and compared with untreated bacterial cells. The results showed that untreated bacterial cells had a regular shape and size, appearing spherical or oval with a regular cytoplasmic membrane without any changes such as shrinkage, pores, or bulges.