Characteristics of Bacterial Strains Isolated from So-Called Vibriosis of Cultured Red Sea Bream in the Winter of 1977

Abstract

The present study was carried out to reveal the characteristics of organism responsible for socalled vibriosis prevailing in cold-water season among cultured red sea bream, Pagrus major.
Nine strains obtained from diseased red sea bream in some culture farms in Nagasaki Prefecture in the mid-winter of 1977 were submitted to the morphological, biochemical and physiological characterization. All the strains were gram-negative, nonsporning short rods with one polar flagellum.Cytochrome oxidase and catalase reactions were all positive. Glucose was fermented with no gas production by these strains. In consideration of these characteristics, the present isolates were tentatively ascribed to Vibrio, although many differences were observed among these strains in the other characteristics. On the basis of the decarboxylation of lysine, arginine and ornithine, it was possible to divide these stains into three groups. In general, the temperature of 20-27°C, the NaCl concentration of 2-3%and the pH of 6-8 were optimal for the growth in peptone water.
Future taxonomic or genetic studies will be necessary to define the present isolates accurately.