Characteristics of the causative bacterium of vibriosis in the kuruma prawn, Penaeus japonicus

Abstract

Seventy-five strains of bacteria, which were isolated from diseased kuruma prawns ( Penaeus japonicus ) in several prefectures of western Japan from 1985 to 1990, were examined for their morphological, biochemical, physiological, serological, genetic, and pathological characteristics. All of these strains were classified as members of one species which seems to be identical to the Vibrio sp. reported as the causative agent of vibriosis in the kuruma prawn. Some selected strains of our isolates were confirmed to be pathogenic to the kuruma prawn by intramuscular injection. The bacterium is a gram-negative, motile, and 0 129 ( Vibrio static compound) sensitive short rod. It does not decarboxylate arginine, lysine or ornithine. The growth ranges (optimum) of temperature, pH and NaCl are 13–31°C (27°C), 6–9 (7–8), and 1–5% (2–4%), respectively. The GC content of DNA was 46.7±0.7 mol%. There was a major common O-antigen among all the tested strains of the pathogen, but it was possible to differentiate the present pathogen from fish pathogenic vibrios by slide agglutination tests. It is proposed that this pathogen is named Vibrio sp. PJ (PJ: Penaeus japonicus ).