Therapeutic potential of honey varieties from Alba county: antimicrobial and antibiofilm effects against resistant pathogens

Abstract

The antimicrobial activity of honey is well documented and results from a complex interplay of physicochemical and biological factors such as low pH, high sugar content, enzymatic antioxidants, phenolic compounds, and microbial metabolites. This study evaluated the antimicrobial and antibiofilm properties of 14 honey varieties from Alba County, Romania, against multidrug-resistant Escherichia coli and Staphylococcus aureus strains isolated from wound secretions. Minimum inhibitory concentration (MIC) was determined by broth microdilution, while biofilm inhibition (PI%) was assessed using the crystal violet microplate assay. MIC values ranged from 8% to 30% (v/v), depending on honey type and bacterial strain. The most effective samples (MIC ≤ 15%) included mountain, forest, raspberry, fir, and polyfloral honeys, while acacia, linden, rape, heather, and dandelion honeys showed lower efficacy (MIC ≥ 25%). Biofilm inhibition rates varied between 55% and 92%, with the highest activity observed in mountains, forest, and polyfloral honeys (PI% ≥ 85%). Statistical analysis revealed significant positive correlations between polyphenol content and antibiofilm activity (r=0.73 for E. coli; r=0.65 for S. aureus, p<0.01). These findings highlight the therapeutic potential of selected honey varieties as natural complementary agents in the prevention and management of multidrug-resistant bacterial infections.