engleski

Antibacterial effect of selected essential oils against Legionella pneumophila

Legionella pneumophila, the causative agent of Legionnaires' disease, is ubiquitously found in aquatic environments. With increasing awareness of legionellosis associtaed with spa and bathtubs, regular clean - up and disinfection becomes essential. In addition to superheating and chlorine disinfection, antibacterial agents extracted from a variety of plants have been increasingly evaluated. The aim of this study was to determine the in vitro anti - Legionella activity of 7 different plant essential oils from Croatia. Using a broth dilution method, the antibacterial activity of 7 different plant essential oils (Immortelle spring and autum oil – Helichrysum arenarium, Sage oil - Salvia officinalis, Laurel oil –Laurus nobilis and Juniper oil –Juniperus communis, Thuja oil - Thuja occidentalis, Chamomile oil - Matricaria chamommilla, Lavandin oil - Lavandula hybrida ) against different L. pneumophila were tested. The minimum inhibitory concentrations (MIC) were determined by visual inspection as the lack of visual turbidity and minimum bactericidal concentration (MBC) as well as no growth after culturing on BCYE agar. Aditionally, the time– kill studies were performed with 106 cfu/mL of L. pneumophila and different plant essential oil at 1xMIC value. The results showed that L. pneumophila is sensitive to all tested essential oils, but the best antibacterial activity was demonstrated with Immortelle summer essential oil, with minimal inhibitory concentration of 0, 1 µg/mL and a bactericidal activity at 0, 2 µg/mL. There was a significant drop in bacterial burden within 48 h with Immortelle summer and autum essential oil, Juniper essential oil, Laural essential oil and Lavandula hybrid essential oil. Our results suggest that Immortelle summer essential, as well as Immortelle autum, Juniper and Laurel oil possess strong anti - Legionella acivities, and have a great potential to be used as a disinfectants in control of legionellosis associated with spa facilities.

Legionella; plant essencial oil; antimicrobial activity

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