In vitro bactericidal effect of various commercial essential oils and their major chemical constituents on Aeromonas salmonicida subsp. Salmonicida
Résumé
Antimicrobial resistance crises lead to restriction of antibiotic treatments. This study aimed to select essential oils (EOs) as alternatives to antibiotics against Aeromonas salmonicida which is a causative agent of furunculosis in salmonid. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 13 EOs and their chemical constituents were determined against four Aeromonas salmonicida subsp. salmonicida strains using broth micro dilution (CLSI). Ceylon cinnamon bark (Cinnamomum zeylanicum / verum), oregano (Origanum vulgare, Origanum compactum, Origanum heracleoticum) and clove (Eugenia caryophyllata) showed high activity with MIC and MBC ≤ 520 μg/ml for at least 3 strains. Thyme with geraniol or thymol (Thymus vulgaris) and thyme satureoides (Thymus satureoides) resulted to moderate activity with MIC and MBC between 520 and 1840 μg/ml for at least 3 strains. Thyme with thujanol or linalool (Thymus vulgaris), tea tree (Melaleuca alternifolia), ravintsara (Cinnamomum camphora) and rosemary with cineole (Rosemary officinalis) showed no activity with MIC and MBC above 3500 μg/ml for at least 3 strains. The combinations of cinnamon with oregano (Origanum vulgare), clove or geraniol thyme EOs did not show a synergistic activity against all strains tested. The major compounds of cinnamon, oregano and clove EOs (cinnamaldehyde, carvacrol and eugenol) demonstrated the highest antibacterial activity, especially cinnamaldehyde (MIC: 62-249 μg/ml and MBC: 62-499 μg/ml). Concerning EOs with no efficiency against the tested strains, their components had also no antimicrobial activity. Our study suggests that EOs of cinnamon, oregano and clove or their main compounds may be tested in in vivo studies.
Domaines
Sciences du Vivant [q-bio]Origine | Fichiers produits par l'(les) auteur(s) |
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