2.6.2. Disk Diffusion Method

The disk diffusion method was used to evaluate the antibacterial activity of hydroethanolic extract of propolis [35]. About 20 mL of Mueller-Hinton agar (MHA) medium was poured into Petri plates. Each Petri plate was inoculated with a bacterial inoculum consisting of 0.5 McFarland (1‐2)∗10⁸ CFU/mL which was prepared in a physiologic saline buffer. Then, sterile Whatman paper disks were placed on a medium and impregnated with 10 μL of hydroethanolic extracts of propolis (100 mg/mL). Ethanol 70% was used as a negative control, to check the possible activity of the solvent of extraction against the tested bacterial strains. After 24 h incubation at 37°C, the inhibition zone was measured in mm. Each experiment was carried out in triplicate.