title: An investigation of the bactericidal activity of selected essential oils to Aeromonas spp.
abstract: Diseases of fishes caused by Aeromonas spp. are common, have broad host ranges and may cause high mortality. Treatments of captive-reared populations using antimicrobials are limited with concerns for bacterial resistance development and environmental dissemination. This study was done to determine whether selected plant-derived essential oils were bactericidal to Aeromonas spp. Initially, twelve essential oils were evaluated using a disk diffusion assay to an isolate of A. salmonicida subsp. salmonicida, cause of fish furunculosis. The greatest zones of inhibition were obtained with oils of cinnamon Cinnamomum cassia, oregano Origanum vulgare, lemongrass Cymbopogon citratus and thyme Thymus vulgaris. Minimum bactericidal concentrations (MBC's) were determined for these four oils, Allimed® (garlic extract, Allium sativum) and colloidal silver to sixty-nine isolates representing nine Aeromonas spp. The lowest mean MBCs (0.02-0.04%) were obtained with three different sources of cinnamon oil. MBCs for three sources of oregano and lemongrass oils ranged from 0.14% to 0.30% and 0.10% to 0.65%, respectively, and for two thyme oils were 2.11% and 2.22%. The highest concentration (5%) of Allimed® tested resulted in MBCs to twelve isolates. A concentration of silver greater than 15 mg/L would be required to determine MBCs for all but one isolate.
authors: USGS Leetown Science Center, National Fish Health Research Laboratory, 11649 Leetown Road, Kearneysville, WV, USA.
authors: Clifford E
authors: CE
authors: Starliper
authors: USGS Great Lakes Science Center, Tunison Laboratory of Aquatic Science, 3075 Gracie Road, Cortland, NY, USA.
authors: Henry G
authors: HG
authors: Ketola
authors: New York State Department of Environmental Conservation, Fish Disease Control Unit, 8314 Fish Hatchery Road, Rome, NY, USA.
authors: Andrew D
authors: AD
authors: Noyes
authors: USGS Leetown Science Center, National Fish Health Research Laboratory, 11649 Leetown Road, Kearneysville, WV, USA.
authors: William B
authors: WB
authors: Schill
authors: New York State Department of Environmental Conservation, Bureau of Fisheries, 625 Broadway, Albany, NY, USA.
authors: Fred G
authors: FG
authors: Henson
authors: USGS Great Lakes Science Center, Tunison Laboratory of Aquatic Science, 3075 Gracie Road, Cortland, NY, USA.
authors: Marc A
authors: MA
authors: Chalupnicki
authors: USGS Great Lakes Science Center, Tunison Laboratory of Aquatic Science, 3075 Gracie Road, Cortland, NY, USA.
authors: Dawn E
authors: DE
authors: Dittman
keywords: Aeromonas; Bactericidal; Essential oil; MBC