engleski

Plant essential oils as an antibacterial agent to control Legionellosis

Legionella are ubiquitous bacteria and are widely distributed in water supply systems (devices for heating, cooling and water evaporation and humidification). Although various disinfection methods have been investigated to reduce Legionella contamination in artificial water sources its control is still a great challenge. In recent years, some studies have showed the efficacy of a variety of essential oils against pathogenic bacteria. However, their antibacterial activity on Legionella was poorly explored. Therefore, the antibacterial activity of 10 plant essential oils was evaluated against Legionella pneumophila. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the essential oils (Hyssop, Palmarosa, Spikenard, Niaouli, Lavandin, Thuja, Chamomile, Juniper, Immortelle-spring and autumn) against L. pneumophila were determined by the broth twofold dilution method in AYE broth. Minimum effective concentration (MEC) in tap water was determined by the water twofold dilution method. MEC was defined as the lowest concentration of the essential oil that allows no growth of Legionella on BCYE agar after 48 hours treatment in tap water. The results showed that L. pneumophila is sensitive to all tested essential oils, but the best antibacterial activity was demonstrated with Spikenard essential oil (MIC=0, 025 mg/mL and MBC = 0, 1 mg/mL). The interaction of the tap water with essential oils reduced the antibacterial effectiveness at both incubation temperatures. In water, the highest antibacterial activity was demonstrated with Juniper and Lavandin essential oils (MEC=0, 2 mg/mL). All essential oils possess good antimicrobial activity against Legionella and therefore have great potential as antibacterial agents in the control and prevention of legionellosis.

plant essential oils; Legionella pneumophila; antibacterial

nije evidentirano