Antibacterial Effect of Eucalyptus Essential Oil

Abstract
Background: To determine minimum inhibitory concentration (MIC) of the Eucalyptus essential oil (EEO) and different antibiotics on Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 27853, and on twenty bacterial isolates from wound swabs (10 S. aureus and 10 P. aeruginosa). In addition, to evaluate the antibacterial effect of combinations of EEO with selected antibiotics.

Methods: Skin infection swabs were cultured; all bacterial isolates were identified according to conventional methods. Ten-gram positive isolates (S. aureus), and ten gram negative isolates (P. aeruginosa) were used to determine MIC of some antibiotics and EEO by broth microdilution methods. Checkerboard method was used to calculate fractional inhibitory concentration indexes.

Findings: EEO exhibited a synergistic activity against S. aureus ATCC 29213 but only gave additive effect against P. aeruginosa ATCC 27853. Outcome of oil/vancomycin combination found to be synergistic in all tested clinical S. aureus isolates from infected wound swabs. While 80% of clinical P. aeruginosa isolates showed additive outcome of EEO/ ceftazidime combination, and only 20% of them gave indifference outcome.

Application: Dermatological applications of EEOs have been growing with great popularity worldwide. It can be used as ointments to treat various dermatological conditions such as abscesses, athlete’s foot, dermatitis, bacterial infections, blisters, boils, burns, cuts, and wounds

Keywords: Bacterial Drug Resistance; Essential Oils; Infected Wounds; Natural Compounds, Synergism.