In Vitro Antimicrobial Activity of Five Turkish Honey Types Against Otitis Externa Pathogens: A Comparative Study

The global rise of antimicrobial resistance underscores the urgent need for alternative therapeutic agents for common infections such as otitis externa. This study aimed to investigate and compare the in vitro antimicrobial activity of five Turkish honey types-thyme, pine, linden, sunflower, and lavender-against eight microorganisms commonly associated with otitis externa.

Honey samples were collected from certified Turkish beekeepers and analyzed for their physicochemical and biochemical properties. Antimicrobial activity was assessed using the broth microdilution method in line with CLSI guidelines. The tested microorganisms included Pseudomonas aeruginosa (ATCC and clinical isolate), Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Enterococcus faecium, Candida albicans, and C. tropicalis. Minimum inhibitory concentrations (MICs) were determined to evaluate antibacterial efficacy.

Thyme honey showed the broadest spectrum of antimicrobial activity (62.5%), with particularly low MICs against P. aeruginosa. Linden and lavender honey inhibited 50% of the tested organisms, with lavender honey being the most effective against S. aureus. Pine honey demonstrated moderate efficacy (25%), whereas sunflower honey showed minimal antimicrobial activity (12.5%). Notably, all honeys were ineffective against both Candida species at the tested concentrations. A strong correlation was observed between total phenolic content and antimicrobial effect, with thyme honey having the highest phenolic and antioxidant values.

Turkish honey, especially thyme honey, demonstrates promising antibacterial activity against otitis externa pathogens. These findings suggest potential for honey-based adjunctive therapies in managing bacterial ear infections, particularly amid rising antibiotic resistance. However, the lack of antifungal efficacy highlights limitations in fungal otitis cases.