Identification and characterization of Streptococcus iniae from farmed American Bullfrogs (Aquarana catesbeiana)

Jingyang Sun; Hua Li; Han Lin; Kesong Chen; Zhendong Qin; Biao Jiang; Wei Li; Qing Wang; Youlu Su; Yanhua Huang; Chun Liu

Aquaculture Reports (Apr 2024)

Identification and characterization of Streptococcus iniae from farmed American Bullfrogs (Aquarana catesbeiana)

Jingyang Sun,
Hua Li,
Han Lin,
Kesong Chen,
Zhendong Qin,
Biao Jiang,
Wei Li,
Qing Wang,
Youlu Su,
Yanhua Huang,
Chun Liu

Affiliations

Jingyang Sun: 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
Hua 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
Han 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
Kesong Chen: 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
Zhendong Qin: 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
Qing Wang: Key Laboratory of Aquatic Animal Immune Technology of Guangdong Province and Key Laboratory of Fishery Drug Development of Ministry of Agriculture, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
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
Yanhua Huang: 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; Correspondence to: Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Guangzhou 510225, 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; Correspondence to: Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Guangzhou 510225, China.

Journal volume & issue: Vol. 35
p. 101980

Abstract

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The American bullfrog (Aquarana catesbeiana) is an economically important aquaculture species in China. Intensive high-density breeding of American bullfrogs has caused a variety of diseases. In this study, we isolated a dominant strain, STR202108, from the viscera of American bullfrogs raised on a bullfrog farm in Guangzhou, Guangdong Province, China, and affected by a disease outbreak that has led to many deaths. We identified the strain as Streptococcus iniae, on the basis of morphological, biochemical and phylogenetic analyses. Regression infection experiments using strain STR202108 indicated that the clinical signs in artificially infected bullfrogs were the same as those in naturally diseased bullfrogs. The typical clinical signs were hepatomegaly with white necrosis, and renal and intestinal bleeding. Histopathological examination indicated that strain STR202108 damaged multiple organs, such as the liver and intestines, in bullfrogs. Drug sensitivity tests showed that STR202108 was sensitive to tetracyclines, macrolides and β-lactam antibiotics. Challenge with high concentrations of the isolated strain STR202108 resulted in a high mortality rate in zebrafish, but no clear clinical signs or death in mice. This study is the first report of Streptococcus iniae infection in American bullfrogs. These results may aid in elucidating the pathogenicity of Streptococcus iniae in a variety of animals, and in controlling and preventing Streptococcus iniae infections in American bullfrogs.

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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