In vitro antibacterial effect of ginger (Zingiber officinale) essential oil against fish pathogenic bacteria isolated from farmed olive flounder (Paralichthys olivaceus) in Korea

The in vitro antibacterial activity of ginger (Zingiber officinale) essential oil (GEO) was tested against five Gram-negative and Gram-positive fish pathgenic bacteria isolated from farmed olive flounder (Paralichthys olivaceus) in Korea. According to the results of disk diffusion, minimum inhibitory and minimum bactericidal concentration (MIC and MBC) tests, GEO was active against most of the bacteria. The range of MIC and MBC values of GEO against the isolates except E. tarda were documented as 0.25-4% (V/V) and 1-8% (V/V), respectively. The MBC/MIC ratio was detected as ≤4, revealing the bactericidal mode of action of GEO against most of the strains. In addition, the multiple antibiotic resistance (MAR) index values ranged from 0.09 to 0.45.