어류 병원성 세균의 항생제 감수성 검사를 위한 MIC panel의 최적화 배양조건 확립

Abstract

No established method can be used to select effective antibiotics in antibiotic susceptibility tests for fish bacterial pathogens quickly and accurately. Existing methods of antibiotics susceptibility tests were complicated and time consuming in the experimental process. The minimal inhibitory concentration (MIC) panel, which can be tested rapidly, have been used for bacteria isolated from human and livestock until now. However fish bacterial pathogens are not suitable for the same method of previous MIC panel. Here, we established the optimal conditions for determining the MIC of major fish bacterial pathogens (Streptococcus spp., Edwardsiella piscicida, Vibrio spp., Aeromonas spp. and Pseudomonas spp.) using the KRAQ1 and CAMPY2 panels.The MIC panel used 18 antibiotics of two types and we conducted experiments to establish the optimal culture medium and temperature for each species. The optimal conditions for incubating Streptococcus spp. were in cation-adjusted Mueller–Hinton broth with TES buffer (CAMHBT) at 28℃, using 5% lysed horse blood (LHB) as recommended by the Clinical Laboratory Standards Institute. For Vibrio spp. the optimal culture conditions were 28℃ in CAMHBT supplemented with 1% NaCl. The optimal conditions for culturing E. piscicida, Aeromonas spp. and Pseudomonas spp. were in CAMHBT at 28℃. Using the optimized conditions established in this study, rapid and accurate test will be possible at the fish farm.