Bactericidal effects of essential oils from clove, lavender and geranium on multi-drug resistant isolates of Pseudomonas aeruginosa

The inhibitory effects of essential oils including clove, lavender and geranium extracted from Eugenia caryophyllata, Lavandula officinalis and Pelargonium graveolens on multi-drug resistant isolates of Pseudomonas aeruginosa were investigated. The main constituents of clove, lavander and geranium oil were eugenol (80-90%), 1,8-cineol (13%) and citronellol (45%) respectively. Clove had the most effective essential oil against P. aeruginosa. A combination consisting of clove, lavender and geranium oils at a ratio of 3:1:1 showed the most inhibitory effect (32-64 jjg/ml) and strong synergy with gentamicin. The essential oils from clove, lavender and geranium exhibited bactericidal activity against multi-drug resistant strains of P. aeruginosa and may be alternatives compounds against these strains in the future.