The antimicrobial activity of honey and propolis extracts from the central region of Romania

Honey and propolis from Apis mellifera (bees) are products that have been used due to their multiple biological properties. The antimicrobial activity of 10 honey samples of known origin and 4 propolis extracts gathered from the same beekeepers located in Transylvania, Romania, were used against certain microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa and Candida albicans. The study also investigated the positive interaction of propolis aqueous extracts when used with poly-floral honey against the same microorganisms. The most sensitive to the activity of honey samples was the S. aureus strain (the largest inhibition area 18 mm) for poly-floral honey and P. aeruginosa strain (17 mm) for sunflower honey, both from Alba County. P. aeruginosa, E. coli, and S. aureus strains (32 mm) were sensitive to the activity of propolis extracts samples. Ciprofloxacin showed a higher antibacterial activity against S. aureus and B. cereus (30 mm). The antimicrobial effect of honey and propolis were more powerful when combined. Statistical analysis showed that both the strain type and the type of honey used influenced the diameter of the inhibition zone. In the case of propolis, no connection between propolis origin (regardless of its concentration) and the microbial activity was found but the microbial strains used influence the diameters of inhibition zones.