Antimicrobial Activity and Chemical Composition of Essential Oils against Pathogenic Microorganisms of Freshwater Fish

Abstract

Antimicrobials are widely applied in aquaculture for treatment of infectious diseases in fish. The increased antimicrobial resistance of fish pathogens to conventional antimicrobial treatment highlights the need for research on the antibacterial properties of natural products—in this case, essential oils (EOs). The aim of the present study was to detect the antimicrobial activity of the essential oils on pathogenic microorganisms found in freshwater fish. Freshwater fish isolates of Aerococcus spp., Aeromonas spp., Enterococcus spp., Escherichia spp., Pseudomonas spp., Shewanella spp., Yersinia spp., and Vagococcus spp. were tested for antimicrobial resistance and antimicrobial activity against 14 commercially available essential oils. Antimicrobial resistance was identified in Pseudomonas spp. isolates against cefepime and ciprofloxacin; while all Aeromonas, Enterococcus, and Yersinia isolates were fully susceptible. All tested EOs revealed antimicrobial activity against the tested freshwater fish isolates at different extents. Cinnamomum camphora exhibited strong antimicrobial activity against Aeromonas spp. (3.12 μL/mL), Enterococcus spp. (0.78–1.56 μL/mL), and Pseudomonas spp. with the MIC method. EOs of Gaultheria procumbens and Litsea cubeba showed strong antibacterial activity against Yersinia spp. and Vacococcus spp. (6.25 μL/mL). The study shows the antimicrobial activity of EOs against the most relevant freshwater fish pathogens and indicates the application opportunities in aquaculture.

Influence of Essential Oils on the Microbiological Quality of Fish Meat during Storage

“…The tested oil can be almost considered as pure linalool. Regarding C. limon EO, the composition is quite similar to that reported by other authors [ 8 , 14 ], with its main component being α-limonene. In the scientific literature it has been reported that the major component of lemon EO is α-limonene, in the range of 51% [ 24 ] to 68% [ 21 ], together with other monoterpenes to complete the profile.…”

“…The composition of the EOs used in the present study showed high similarities with those of Klüga et al [ 8 ]. Few studies are available on C. camphora , and specifically on the chemotype Linaloolifera.…”

“…Chemical composition of essential oils: Chemical characterization of essential oil samples was determined by gas chromatography/mass spectrometry (GC/MS) and gas chromatography (GC-FID), according to method provided by Kluga et al [ 8 ].…”

“…The antimicrobial effects of different essential oils on freshwater fish as a strategy to reduce antimicrobials in aquaculture has been recently investigated by several authors [ 8 ]. In their study, they evaluated the composition of 14 essential oils and their inhibitory activity (disc diffusion assay, DDA, and minimum inhibitory concentration, MIC) against 20 bacteria isolated from freshwater fish.…”

Chemical Composition and Anti-Microbial Activity of Hog Plum (Spondias mombin L.) Peel Oil Extracted from Different Regions of Tropical Climates

“…The products of medicinal plants like EOs and their antimicrobial properties have been empirically recognized for centuries, but recently the antimicrobial properties have been studied and confirmed scientifically [13][14][15]. These EOs effectively control the growth of different microorganisms like fungus, yeasts, bacteria, etc., which has been reported in several studies [16][17][18][19][20][21]. The bark extract of hog plums exhibits a valuable antibacterial activity, while the aqueous extract of the bark has shown a moderate antibacterial activity against Escherichia coli, Salmonella typhimurium, and Vibrio cholerae [22,23].…”