Comparative study on the in vitro antibacterial activity of Australian teatree oil, cajuput oil, niaouli oil, manuka oil, kanuka oil, and eucalyptusoil

To compare the antibacterial activity of the Australian tea tree oil (TTO) with various other medicinally and commercially important essential myrtace ous oils(cajuput oil, niaouli oil, kanuka oil, manuka oil, and eucalyptus o il) the essential oils were first analysed by GC-MS and then tested against various bacteria using a broth microdilution method. The highest activity was obtained by TTO, with MIC values of 0.25% for Enterobacter aerogenes, E scherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella chole raesuis, Shigella flexneri, Bacillus subtilis, Listeria monocytogenes, Stap hylococcus aureus, S. saprophyticus, and S. xylosus. It is noteworthy that manuka oil exhibited a higher activity than TTO against gram-positive bacte ria, with MIC values of 0.12%. Both TTO and manuka oil also demonstrated a very good antimicrobial efficacy against various antibiotic-resistant Staph ylococcus species. Pseudomonas aeruginosa was resistant to all essential oi ls tested, even at the highest concentration of 4%.