The Study of the Antimicrobial Activity of Transylvanian (Romanian) Propolis

The aim of the present study was to investigate the antibacterial activity of propolis samples collected from various regions in Transylvania (Romania) against six bacterial strains: three Gram-positive bacteria (Staphylococcus aureus ATCC 6538P, Bacillus cereus ATCC 14579, Listeria monocytogenes ATCC 7644), two Gram-negative bacteria (Escherichia coli ATCC 10536, Pseudomonas aeruginosa ATCC 27853) and one yeast strain (Candida albicans ATCC 90028). Ethanolic extracts of the studied samples were prepared for the evaluation of antimicrobial activity, which was appreciated by measuring the inhibition zones diameters. The methodology used was agar diffusion technique inside Petri dishes with nine wells. Enroxil was used as control. A better sensibility of the Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes) was noticed; the diameter of the inhibition zones ranged between 8 mm and 17 mm. As for Gram-negative bacteria, results were different for every tested bacterial strain. Inhibition zones diameter for E. coli ranged between 7 mm and 12 mm, while for P. aeruginosa a total resistance was noticed. Inhibition zones diameters for Candida albicans showed a variation which ranged between 0 mm and 10 mm. Minimum inhibitory concentration (MIC) was evaluated for sample PS 20 due to the positive results showed against Staphylococcus aureus. According to the results obtained, it might be concluded that the tested propolis samples showed good results against Gram-positive bacteria