Antimicrobial activity of honey bee venom against select infectious fish pathogens

In this study, bee venom (BV) isolated from honey bees Apis mellifera was assessed for its potential use as an antimicrobial agent against fish pathogenic bacteria. We used three bacterial isolates (Edwardsiella tarda, Vibrio ichthyoenteri, and Streptococcus iniae) that were originally obtained from the gastrointestinal tracts of moribund Olive Flounder Paralichthys olivaceus. Bee venom exhibited antibacterial activity against all three infectious fish pathogens. The minimum inhibitory concentration and minimum bactericidal concentration (mean ± SE) of BV were 17.6 ± 2.6 and 34.9 ± 3.4 'g/mL, respectively, against E. tarda; 1.76 ± 0.3 and 6.8 ± 2.6 'g/mL against V. ichthyoenteri; and 3.49 ± 0.9 and 11 ± 1.6 'g/mL against S. iniae. The postantibiotic effect of BV was 5 ± 0.6 h for E. tarda, 6 ± 0.3 h for V. ichthyoenteri, and 7 ± 0.6 h for S. iniae. In addition, the antimicrobial activity of BV was not pH dependent, as inhibition zones were identical at pH levels ranging from 2 to 11. These results indicate that BV inhibits the growth and survival of bacterial strains and that BV may be a useful complementary antimicrobial agent against fish pathogenic bacteria.