engleski

Anti – Legionella activity of selected plant essential oils from Croatia

Legionnaires disease is one of the most common cause of hospital and community acquired atypical pneumonia. Legionella are Gram negative facultative intracellular bacteria and may grow in hot spring water and hot water outlets of hospitals, hotels and private apartments. 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. A variety of essential oils, the natural mixtures of volatile compounds extracted from plants, show biocidal effect on bacteria, fungi, viruses and protozoa. The aim of this study was to determine the in vitro anti-Legionella activity of 5 different plant essential oils from Croatia. Using a broth dilution method, the antibacterial activity of 5 different plant essential oils (Immortelle spring and autum oil –Helichrysum arenarium, Sage oil -Salvia officinalis, Laurel oil –Laurus nobilis and Juniper oil –Juniperus communis) against different L. pneumophila and L. longbeachae strains were tested. Different concentrations of plant essential oils (25, 6 µg/mL – 0, 025 µg/mL) were tested against each bacterial strain. 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 afterr culturing on BCYE agar. The results showed that L. pneumophila and L. longbeachae are sensitive to all tested essential oils, but the best antibacterial activity was demonstrated with Immortelle spring essential oil, with minimal inhibitory concetration (MIC) of 0, 4 µg/mL and 0, 1 µg/mL and a bactericidal activity at 0, 8 µg/mL and 3, 2 µg/mL. Our results suggest that Immortelle spring essential oil possess strong anti - Legionella acivities, and have a great potential to be used as a disinfectant agent in control of legionellosis associated with spa facilities.

Legionella; plant essencial oil; antimicrobial activity

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