engleski

Anti-Legionella potential of Immortelle, Rosemary and Lavandine hydrolates

Legionella pneumophila is a ubiquitous bacterium with affinity for aquatic habitats such as lakes, rivers, wetlands and moist soil. Legionella can be found in swimming pools, spas, saunas and showers. Except the usual techniques of prevention of Legionella there are natural methods such as essential oils and their products, like hydrolates. Hydrolates are floral waters that hold similar molecular properties like oil, and unlike them are soluble in water. They have strong antibacterial, antiviral, antifungal and anti-inflammatory properties. The aim of the study was to investigate the antimicrobial and antiaggregative activities of immortelle hydrolate (Helichrysum italicum), rosemary hydrolate (Rosmarinus officinalis) and lavandine hydrolate (Lavandula hybrida) from Hvar Island (Croatia) to Legionella pneumophila 130b. The results of microdilution method performed in Buffered Yeast Extract (BYE) broth and sterile tap water (STW) showed that L. pneumophila is sensitive to all tested hydrolates. The best antibacterial activity in BYE broth had lavandine and rosemary hydrolates, with a MIC (minimal inhibitory concentration) and MBC (minimal bactericidal concentration) of 25% (w/v), lower activity had immortelle (Helicrysum italicum) with MIC and MBC of 50% (w/v). Great antibacterial activity of hydrolates was found also in STW where MICs/MBCs were 6.25%, 12.5% and 25.0% (w/v) with rosemary, lavandine and immortelle hydrolate, respectively. All results were confirmed with growth curves. Aggregations of L. pneumophila cells in BYE broth and STW with the addition of hydrolates at a concentration of ¼ MIC increased (from 5% -30%) and further researches are needed. As lavandine, rosemary and immortelle hydrolates have anti-Legionella activities they have a great potential applications in the control and prevention of legionellosis.

Legionella pneumophila; rosemary; lavandine; immortelle; hydrolate; antimicrobial activity

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