An Essential Oil Blend Prevents Pseudomonas aeruginosa PA01 from Forming Biofilms

International audienceEssential oils are natural ingredients exhibiting antimicrobial and antioxidant effects. The properties of a mix of Allium sativum, Cinnamomum cassia and Mentha piperita essential oils are established in this study on a biofilm forming pathogen, Pseudomonas aeruginosa PA01.Minimal inhibitory and bactericidal concentrations were first determined on planktonic cells for the pure essential oils, then for the blend. A crystal violet assay provided the active concentration of a blend for bacterial biofilm. Pseudomonas aeruginosa PA01 planktonic and sessile cells were affected by a concentration of an essential oil blend of 0.125%. The active concentration of 0.1% was confirmed using a protocol developed on glass slides, for its activity on adhesion and biofilm formation. The experiment was then repeated in flow cells to monitor the structural biofilm development using confocal laser scanning microscopy. Pseudomonas aeruginosa PA01 adhesion was severely inhibited by the blend concentration at 0.5%. Its biofilm was strongly affected from a 0.1% blend concentration and was totally eradicated when the concentration reached 1%.The essential oil blend has an enlarged spectrum of activity and is effective on early biofilm development stages, with a concentration that does not involve bactericidal activities. These results are predictive for potential use of this blend as a cleanser