Edwardsiella piscicida, a pathogenic bacterium newly detected in spotted sea bass Lateolabrax maculatus in China

Jianmei Hu; Baotun Wang; Juan Feng; Chun Liu; Biao Jiang; Wei Li; Li Lin; Youlu Su

Aquaculture Reports (Feb 2022)

Edwardsiella piscicida, a pathogenic bacterium newly detected in spotted sea bass Lateolabrax maculatus in China

Jianmei Hu,
Baotun Wang,
Juan Feng,
Chun Liu,
Biao Jiang,
Wei Li,
Li Lin,
Youlu Su

Affiliations

Jianmei Hu: Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; Key Laboratory of South China Sea Fishery Resources Development and Utilization, Ministry of Agriculture and Rural Affairs, Guangzhou 510300, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China
Baotun Wang: Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; Key Laboratory of South China Sea Fishery Resources Development and Utilization, Ministry of Agriculture and Rural Affairs, Guangzhou 510300, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China
Juan Feng: Key Laboratory of South China Sea Fishery Resources Development and Utilization, Ministry of Agriculture and Rural Affairs, Guangzhou 510300, China
Chun Liu: Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
Biao Jiang: Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
Wei Li: Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
Li Lin: Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; Corresponding author.
Youlu Su: Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; Corresponding author.

Journal volume & issue: Vol. 22
p. 100973

Abstract

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In this study, Edwardsiella piscicida strain 18BJ136 was isolated from diseased spotted sea bass Lateolabrax maculatus, in China, and its pathogenicity in this newly recognized host was investigated. Physiological and biochemical tests showed that 18BJ136 did not produce H2S but utilized d-maltose, and was positive for succinate alkalinization, coumarate, and the ellman reaction. Its growth characteristic showed that it proliferated in a wide range of salinities, but was sensitive to acidity and alkalinity. A PCR analysis showed that 18BJ136 carried at least nine virulence genes: gadB, katB, citC, usp13, esrB, sodB, luxS, fimA, and mukF. A spot test showed that the strain had a variety of extracellular enzyme activities, including hemolysin and protease. Artificial infection experiments indicated that 18BJ136 was strongly virulent in the spotted sea bass, with a median lethal dose (LD50) of 1.23 × 103 cfu/g. Similar to the naturally infected fish, the main clinical symptoms of the artificially infected fish were festering scores of skin, scale shedding, and the swelling of multiple internal organs. The 18BJ136 caused the following histopathological lesions in the spotted sea bass: different degrees of inflammation in each tissue; multiple necrotic foci in the liver, spleen, and head kidney; and severe hemorrhage in the spleen and head kidney. The expression of IL-8, TNF-α, TLR-23, and HSP70 was significantly upregulated after infection (P < 0.05), indicating that the pathogen activated the host’s innate immune response. These results extended our understanding of E. piscicida infection in the spotted sea bass.

Published in Aquaculture Reports

ISSN: 2352-5134 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Agriculture: Aquaculture. Fisheries. Angling
Website: http://www.journals.elsevier.com/aquaculture-reports/

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