Characteristics of Pathogenic Vibrio sp. Isolated from Cultured Yellowtail Seriola quinqueradiata

양식방어에서 분리한 병원성 Vibrio균의 특성에 대하여

Vibriosis has caused severe losses among cultured yellowtail (Seriola quinquerediata) at some cage farms in Korea in recent years. Major object of this study was to investigate the causative organism of the diseased cultured yellowtail. The samples were collected from the aquarium of Fisheries Research & Development Agency during the period from November 1984 to January 1985. The experimental results are summarized as follows ; Among the isolated bacteria from the diseased yellowtail, Vibrio sp. isolated from the kidney was considered to he the causative organism. Tetracycline, chloramphenicol and gentamycin were observed as bacteriostatic agents to the pathogenic strain, but sulfisomezole and sulfisoxasole were not. When the isolated strain was injected intramuscularly to yellowtail, rid sea-bream, rock-bream and common carp, it had virulence at $25^{\circ}C$ to all fish examined but to virulence at $15^{\circ}C$ except for yellowtail.

양식방어(Seriola quinqueradiata)에 vibrio병이 발생하여 상당한 피해를 입고 있다. 본 연구는 양식방어에 발생한 vibrio병의 원인균에 대한 생화학적 성상, 생물학적 성상, 약제감수성및 병원성을 검토한 것으로 결과는 아래와 같다. 1. 병어의 신장에서 원인균을 분리하였으며 생화학적 성상, 생물학적 성상을 조사하여 Vibrio sp.로 동정하였다. 2. 분리균이 발육할 수 있는 NaCl농도는 $0.5{\sim}7\%$(최적농도; $3\%$), pH의 경우는 $6{\sim}10$(최적; 9)였다. 3. 분리균은 tetracycline, chloramphenicol, gentamycin에 감수성을 나타내었으나, sulfisomezole, sulfisoxazole이는 감수성이 없었다. 4. 수온에 따르는 병원성은 $25^{\circ}C$에서는 모든 접종어에 병원성을 나타냈으나, $15^{\circ}C$에서는 방어만 병원성을 나타냈다.