Inhibition and antibacterial effect of trichloroisocyanuric acid and benzalkonium bromide on Vibrio spp. from marine aquaculture

To study the resistance of Vibrio spp. isolated from marine aquaculture to trichloroisocyanuric acid (TCCA) and benzalkonium bromide (BB), we applied microdilution technique to determine the minimum inhibitory concentration (MIC) of the two disinfectants to 198 strains of Vibrio spp., andconducted aquantitative suspension test to evaluate bactericidal activity of the two disinfectants to two strains of V.parahaemolyticus. The results show that the MICs of TCCA and BB for 198 strains of Vibrio spp. were 31.13~498.00 mgL-1 and 20.00~160.00 mgL-1, respectively. In quantitative suspension test, the effective killing time prolonged as the TCCA and BB concentrations decreased. The strains FJ244 and FJ246 could be effectively killed by 7.78 mgL-1 of TCCA in 4 min and 15.56 mgL-1 of TCCA in 4 min, respectively; while the strains could be effectively killed by 20.00 mgL-1 of BB in 3 min and 10 mgL-1 of BB in 40 min, respectively. When the concentrations of the two disinfectants were reduced to the half, the disinfectants failed to kill V.parahaemolyticus even if the action time prolonged.