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Isolation and characterization of pathogenic Vibrio alginolyticus from diseased cobia Rachycentron canadum
Author(s) -
Liu PingChung,
Lin JiYang,
Hsiao PeiTze,
Lee KuoKau
Publication year - 2004
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.200310316
Subject(s) - vibrio alginolyticus , microbiology and biotechnology , lethargy , biology , agar , outbreak , peritoneal cavity , ascites , agar plate , bacteria , vibrio , anatomy , virology , medicine , genetics
Outbreaks of serious mortality among cultured juvenile cobia Rachycentron canadum L . (weighing 8–10 g) characterized by lethargy, dark skin and ascites in the peritoneal cavity while some fish possessing damaged eyes occurred in July and August of 2001 in Taiwan. Fifteen motile bacterial strains were isolated from head kidney and/or the ascites on tryptic soy agar supplemented with 1% NaCl (TSA1) and/or thiosulphate citrate bile salt (TCBS) sucrose agar plates during the two outbreaks. All the isolates were characterized and identified as Vibrio alginolyticus on the basis of biochemical characteristics, and comparisons with those of the reference strain V. alginolyticus ATCC 17749. The strain C3c01 (a representative of the 15 similar field isolates), was virulent to the cobia with an LD50 value of 3.28 × 10 4 colony forming units/g fish body weight. All the moribund/dead fish exhibited lethargy, dark skin and ascites in the peritoneal cavity as that observed in natural outbreaks. The same bacteria could be reisolated from kidney and the ascites of fish after bacterial challenge using TSA1 and TCBS plates. The results reveal that V. alginolyticus is an infectious agent of vibriosis in the cobia.