Bacterial Growth Inhibition Test

The third experiment was designed and conducted using the diffusion method in accordance with the EUCAST criteria.¹⁴ Mueller-Hinton agar (Becton Dickinson, Warsaw, Poland) plate, 4 mm in depth, was used in antimicrobial susceptibility testing.

E coli (ATCC 25922) strain was grown in blood agar base for 18 hours at 37°C, then suspended in saline to reach 0.5 on the McFarland scale (1-2 × 1.5 × 10⁸ CFU [colony-forming units]/mL). Sterile swab was dipped into the bacterial suspension and inoculated onto agar plate. Then, each DEBN (from group III) was placed on this surface and incubated for 18 hours at 35°C. The results were evaluated visually by observing the appearance or absence of zones of bacterial inhibition surrounding DEBN. The minor axis of bacterial growth inhibition zones was measured.