Vapour-phase activities of essential oils against antibiotic sensitive and resistant bacteria including MRSA

To determine whether essential oil (EO) vapours could reduce surface and airborne levels of bacteria including methicillin-resistant Staphylococcus aureus (MRSA). The antibacterial activity of geranium and lemongrass EO individually and blended were evaluated over a range of concentrations by direct contact and vapour diffusion. The EO were tested in vitro against a selection of antibiotic-sensitive and -resistant bacteria, including MRSA, vancomycin-resistant Enterococci (VRE), Acinetobacter baumanii and Clostridium difficile. An EO blend containing lemongrass and geranium was used to formulate BioScent(TM) that was dispersed into the environment using the ST Pro(TM) machine. The effects were variable depending on the methods used. In a sealed box environment, MRSA growth on seeded plates was reduced by 38% after 20 h exposure to BioScent(TM) vapour. In an office environment, the ST Pro(TM) machine dispersing BioScent(TM) effected an 89% reduction of airborne bacteria in 15 h, when operated at a constant output of 100%. EO vapours inhibited growth of antibiotic-sensitive and -resistant bacteria in vitro and reduced surface and airborne levels of bacteria. Results suggest that EO vapours, particularly Bioscent(TM), could be used as a method of air disinfection.