Vibrio harveyi의 병원성에 관한 연구

Abstract

Vibrio harveyi, the major causal agent of vibriosis, affects a diverse range of marine vertebrates and invertebrates over a wide geographical area. The aims of this study were to investigate the characteristics of pathogenic V. harveyi isolated from diseased marine fish and shrimp and the infection in fish and shrimp, and histopathological traits of internal organs infected by the pathogen. Four strains of V. harveyi isolated from marine fish (FR2 and ATCC 35084) and shrimp (VIB 391 and ATCC 14126) were used in this study. The V. harveyi cultures produced ECPs showing and various enzymatic activites (caseinase, gelatinase, phospholipase, lipase, haemolysin and chitinase activity). Both bacterial cells and ECPs of V. harveyi showed haemolytic activity and VIB 391 decomposed chitin. The survival rate of V. harveyi FR2 was higher than other strains in the skin and gut mucus of olive flounder, Paralichthys livaceus and black rockfish, Sebastes schlegeli and its ECPs showed strong cytotoxic effect on haemocytes of the shrimp and macrophages of the fish. The V. harveyi isolates regardless the possession of luminescence were virulent to fleshy prawn, Fenneropenaeus orientalis (30 days post-hatch) and adult white leg shrimp, Litopenaeus vannamei, but they did not kill white leg shrimp (30 days post-hatch). V. harveyi cause mortalities by necrotizing the hepatopancreas of fleshy prawn and sloughing off the epithelial cells of the intestine of black rockfish.