Detection of Aeromonad Bacteria in Tissues of the Carp with Fluorescent Antibody Techniqes

Both Aeromonas hydrophila and Aeromonas salmonicida were injected into the skin of carps(23g in mean body weight) with 0.1ml of PBS containing A.hydrophila 106 CFU＋A.salmonicida 106 CFU /ml,A.hydrophila 107 CFU＋A.salmonicida 107 CFU/ml,A.hydrophila 106 CFU＋A.salmonicida 108 CFU/ml and A.hydrophila 105 CFU＋A.salmonicida 109 CFU/ml. The injected lesions were studied with histopathological and indirect fluorescent antibody techniques(IFAT). All injected lesions showed necrosis,hemorrhage and bacterial multiplication in the skin and lateral musculature. IFAT used the absorbed anti-A.hydrophila-serum markedly revealed fluorescent antibody response in all injected lesions, indicating the bacterial multiplication in tissues. On the other hand,IFAT used the absorbed anti-A.salmonicida-serum narrowly revealed fluorescent antibody response in the lesions in which A.hydrophila 105 CFU＋A.salmonicida 107 CFU and A.hydrophila 104 CFU＋A.salmonicida 108 CFU were injected. These results indicated that A.hydrophila more dominantly multiplied in the carp tissues than A.salmonicida when they were mixed. The indirect fluorescent antibody technique used absorbed antisera proved to be an effective and useful method for bacterial distinction in lesions where bacteria belonging to the same genus were mixed