Antimicrobial and Antibiofilm Activity of Acacia and Polyfloral Honey: Physicochemical Characterization and Correlation with Antibacterial Efficacy

Honey has been appreciated for its medicinal properties since ancient times; it is known as a powerful antimicrobial agent, and as a result of the increase in antibiotic resistance of various bacterial strains, honey began to be used in complementary therapies to combat microbial infections. The study aimed to identify the antimicrobial potential of two honey varieties (Acacia honey and polyflora honey) with different botanical and geographical origins on standardized bacterial strains or isolated from patients, some of which showed antibiotic resistance. The physicochemical parameters of the honey varieties analyzed were: water content, impurities, pH of honey, acidity, mineral content, reducing sugar content, total phenol content, and antioxidant capacity (DPPH). The antibacterial potential of the honey varieties was assessed based on tests to determine cell viability and the capacity to inhibit biofilm formation. The Gram-positive strains studied were Staphylococcus aureus (ATCC25923), Staphylococcus aureus MRSA (ATCC43300), Streptococcus pneumoniae (ATCC49619), and the Gram-negative strain was Escherichia coli (ATCC25922). In addition, bacterial strains isolated from the patients were Staphylococcus aureus, Staphylococcus aureus MRSA, Streptococcus pneumoniae, and Escherichia coli. The results of the microbiological tests were correlated with the physicochemical parameters, suggesting that the content of polyphenolic compounds with antioxidant activity and acidic pH may contribute to the antimicrobial potential of honey. Also, statistical analyses indicated significant differences regarding the antimicrobial potential of honey on Gram-positive versus Gram-negative bacteria, standardized versus isolated bacteria from patients, but also for antibiotic-resistant bacteria compared to the other strains studied.