On the Scent of a Remedy for MRSA and VRE

ABSTRACT & COMMENTARY

Synopsis: Oils from tea, thyme, peppermint, and lavender but not juniper kill MRSA and VRE in vitro.

Source: Nelson, RRS. J Antimicrob Chemother 1997;40:305-306.

Nelson studied in vitro activities of five plant essential oils against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium.

Essential oils from the tea tree, thyme, juniper, peppermint, and lavender were tested for their bacteriostatic and bactericidal activities against 15 strains of MRSA and five strains of VRE. Minimum inhibitory and bactericidal concentrations ranged from 0.25% to 2% oil for the oils, except for juniper, which failed to show an effect at 2%. Tea tree oil was twice as potent as the others.

COMMENT BY J. PETER DONNELLY, PhD

Heretofore, such reports were regarded as off-beat, but it is gratifying to see them now appearing in mainstream journals. After all, plant oils have been used for centuries in perfumes as well as to cleanse, soothe, and heal, and tea oil has been used as an antiseptic in Australia since the 1920s. Pity about the juniper, though, since this has also long been used both as an antiseptic and to flavor alcohol in jenever (Dutch-gin) and gin. (The latter is unlikely to deter fans from taking their liquor for medicinal purposes!)

Nelson points out that essential oils not only smell good but have a "green" image and are already available commercially at 5-10 times the minimum concentrations necessary for topical antibacterial use. However, Nelson also expresses concern that their widespread use in cosmetics at subinhibitory concentrations might undermine their potential for antisepsis. I doubt that, given that they kill more than 99.9% of bacteria at the same concentration as inhibits growth, suggesting a rapid lethal assault perhaps on multiple vital bacteria cell components simultaneously. Nevertheless, if the potential efficacies of these oils can be substantiated in clinical trials, not only would we have more environmentally friendly remedies for dealing with these two particularly troublesome nosocomial potential pathogens, but patients are likely to prefer them to more orthodox products if only because they will smell better. These data are also good news for heterodox medicine and will hopefully stimulate scientists to explore oils from other plants, particularly those from countries long used to employing plants for medicinal purposes.