Antimicrobial effect of bee honey in comparison to antibiotics on organisms isolated from infected burns

Despite recent advances in antimicrobial chemotherapy and burn wound management, infection continues to be an important problem in burns. Honey is the most famous rediscovered remedy that is used to treat infected wounds and promote healing. The present study aims to evaluate the antimicrobial effect of bee honey on organisms isolated from infected burns in comparison to the antibiotics used in treatment of burn infection, and to evaluate the effects produced when bee honey is added to antibiotic discs. Thirty patients with burn infection were selected for this study. The collected specimens were cultured on blood agar plates. The isolated colonies were identified by different methods. The isolated organisms were inoculated onto Müller-Hinton agar. Each agar plate was divided by a marker pen into two halves - in one half the antibiotic discs were plated while on the opposite side each antibiotic disc, immersed in honey, was plated opposite to the same antibiotic disc. At the centre of the agar, a sterile filter paper disc immersed in honey was applied. The most frequently isolated organism was Pseudomonas aeruginosa, representing 53.3% of the isolates. The mean inhibition zones (in mm) produced by honey (18.2 ± 2.5 mm) when applied to isolated gram-negative bacteria were significantly higher than amoxicillin/clavulinic acid, sulbactam/ampicillin, and ceftriaxone (p1 = 0.005 for each). When honey was added to the antibiotic discs there was highly significant increased sensitivity of isolated gram-negative bacteria compared with each of the antibiotic discs alone and with honey alone. The susceptibility of isolated staphylococci revealed the synergistic effect of added honey to the antibiotic discs tested. The antimicrobial effect of honey (18.7 ± 2.2 mm) was significantly higher than antibiotics - ciprofloxacin, sulbactam/ampicillin, ceftriaxone, and vancomycin (p1 ≤ 0.05 for each). After the addition of honey to the tested antibiotic discs there were highly significant increased inhibition zones of antibiotic mixed with honey compared with antibiotic alone - ciprofloxacin, vancomycin, and methicillin (p3 ≤ 0.001 for each). Also, the increase was significant compared with antibiotics alone - imipenem, amoxicillin/clavulinic acid, and ceftriaxone (p3 ≤ 0.05). In conclusion, honey had more inhibitory effect (85.7%) on isolated gram-negative bacteria (Pseudomonas aeruginosa, Enterobacter spp., Klebsiella) than commonly used antibiotics, while it had an inhibitory effect on all methicillin-resistant Staphylococcus aureus (100%) compared with antibiotics used. A synergistic effect of honey was observed when it was added to antibiotics for gram-negative bacteria and also for coagulase-positive staphylococci.