Phenotypic and genetic characterization of bacteria isolated from diseased cultured sea cucumber Apostichopus japonicus in northeastern China

Diseases of Aquatic Organisms

Hua Li¹  Soo-Il Park¹  Sung-Ho Woo¹  De-Hai Xu¹  Guo Qiao¹  Qiang Li¹  Wei Zhou¹  Jie-Quan Gu¹ 

关键词: Sea cucumber;    Apostichopus japonicus;    Bacterial pathogen;    Vibrio splendidus;    Shewanella sp.;    Pseudoalteromonas tetraodonis;   

DOI  :  10.3354/dao02254

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: During the winter–spring from 2004 to 2006 in northeastern China cultured Japanese sea cucumber Apostichopus japonicus suffered from a serious disease. Clinical signs included swollen mouth, skin ulceration and massive mortality. Clinical samples taken during this period were studied. Thirty-one bacterial samples were isolated from diseased sea cucumbers and identified through biochemical tests, 16S rRNA gene sequence analysis and PCR amplification, followed by pathogenicity determination. The results showed that the 31 isolates belonged to the genera Vibrio (64.5%), Shewanella (12.9%), Serratia (12.9%), Pseudoalteromonas (6.4%) and Flavobacterium (3.2%). The 3 prominent strains were Vibrio splendidus (41.9%), Shewanella (12.9%) and Serratia odorifera biogroup I (12.9%). Pathogenicity tests demonstrated that 13 out of 31 isolates were pathogenic, including 8 strains of V. splendidus, 3 strains of Shewanella sp. and 2 strains of Pseudoalteromonas tetraodonis. The pathogenic V. splendidus showed the highest frequency of appearance. Median lethal dose (LD₅₀) values (14 d) of V. splendidus, Shewanella sp. and P. tetraodonis were 1.74 × 10⁷, 7.76 × 10⁶, 7.24 × 10⁷ CFU g^–1 body weight of sea cucumber, respectively. The virulences differed by species: Shewanella sp. > V. splendidus > P. tetraodonis. This is the first report of Shewanella sp. virulence in sea cucumber.

【 授权许可】

Unknown