Honey and propolis reduce the antibacterial resistance of staphylococci

Abstract

Antimicrobial resistance (AMR) is a significant public health concern of the 21st century, contributing to an increasing number of deaths in both human and veterinary medicine. Multi-antibiotic-resistant bacteria, such as S. aureus, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecium, Streptococcus pneumoniae, and Klebsiella pneumoniae, pose substantial challenges. This research investigated changes in antibiotic susceptibility of Staphylococcus spp. Isolates from extensively farmed pigs (n = 421) when exposed to different types of honey (multi-floral, n = 1, and rapeseed, n = 2) or different commercial propolis concentrations (20% and 30% in 70% ethanol). Thirty species of staphylococci were identified using classical bacteriology techniques. Initial antimicrobial resistance/susceptibility was tested against colistin, erythromycin, sulfamethoxazole/ trimethoprim, penicillin, florfenicol, vancomycin, tetracycline, imipenem, marbofloxacin, cefoxitin, clindamycin, and methicillin using the Kirby Bauer disk-diffusion method. Following exposure to bee products, susceptibility to antibiotics was reassessed using the same protocol. The MAR index and percentage of strains resistant to each antibiotic were calculated. Results showed a relatively low MAR index in 90% of the strains, with 26.7% showing no resistance, 20% with a MAR index of 0.08, and 43.3% with a MAR index of 0.16. However, 10% of the strains exhibited mild resistance or high resistance (MAR index of 0.25, 0.33, and 0.58), posing risks to animals, caretakers, and the environment. Following exposure to bee products, changes in susceptibility to different antibiotics were observed. The highest number of strains initially classified as resistant and reclassified as sensitive were found for penicillin and tetracycline, followed by sulfamethoxazole, methicillin, and cefoxitin. Changes were more pronounced in strains classified as moderately resistant, with significant differences (p < 0.05-p < 0.001) observed between antibiotics. The findings suggested that honey and propolis could reduce antimicrobial resistance in staphylococci isolated from healthy pigs, thus serving as natural alternatives to antimicrobial treatment for staphylococcal infections.