Characteristics of Vibrio damsela Isolated from Diseased Yellowtail Seriola quinqueradiata

Abstract

An aerogenic Vibrio strain Yp-16 was isolated from diseased young fish of yellowtail Seriola quinqueradiata cultured in Shibushi Bay, Japan. On the basis of specific characters such as O/129 sensitivity, lysine decarboxylase (-), indole (-), casein hydrolysis (-), V. P. (+), DNase (+), and acid and gas production from glucose, galactose, fructose, mannose and maltose, the isolate was identified as Vibrio damsela. It is feasible to differentiate V. damsela strain Yp-16 from other Vibrio spp. on TCBS(T) agar composing of TCBS and trehalose (1%). V. damsela strain Yp-16 was demonstrated to have hemolytic activity to fish erythrocytes and cytotoxic activity to eel nonparenchymal hepatocytes. Yellowtail dead fish injected intramuscularly with strain Yp-16 had hemorrhage in the internal organs, fins and gills, and the same bacterium was reisolated in the livers.