The antimicrobial activity of the essential oils displayed considerable
variations among the different Eucalyptus species. The
essential oil of E. staigeriana showed the highest activity against
all the microorganisms tested, especially against the pathogen S.
aureus with an inhibition zone greater than 90 mm (the growth
of the organism was inhibited over the entire Petri dish). E. dives
exhibited a considerably stronger activity than that of E. olida when
tested against S. aureus, but the two Eucalyptus species showed
similar activity against the Gram-positive E. faecalis and the yeast
C. albicans. Essential oils from E. oilda showed no inhibitory activity
against the Gram-negative bacterium P. aeruginosa