2.7. Preparation of Bacterial Suspension and Inoculum for Antibacterial Tests

Antibacterial properties were tested via the disk diffusion test, also known as the Kirby-Bauer disk diffusion method, which is a standardized method used in microbiology laboratories in order to determine bacterial susceptibility against antibiotic substances. Bacterial suspension of Staphylococcus aureus (ATCC 25923) reference culture was prepared according to EUCAST (European Committee on Antimicrobial Susceptibility Testing) standards in optic density of 0.5 according to McFarland standard with McFarland optic densitometer (Biosan, Riga, Latvia). Bacterial suspension was inoculated onto a sterile Mueller–Hinton (MH) agar (Oxoid, Altrincham, UK) with a sterile cotton swab.