African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5233

Full Length Research Paper

Nocardia seriolae, a causative agent of systematic granuloma in spotted butterfish, Scatophagus argus, Linn

Pei-Chi Wang
  • Pei-Chi Wang
  • Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan, ROC
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Ming-An Tsai
  • Ming-An Tsai
  • Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan, ROC
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Yu-Chi Liang
  • Yu-Chi Liang
  • Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan, ROC
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Yanting Chan
  • Yanting Chan
  • Diagnostic and Prevention Center of Livestock Diseases, Ilan, Taiwan, ROC
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Shih-Chu Chen*
  • Shih-Chu Chen*
  • Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan, ROC
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  •  Received: 03 May 2014
  •  Accepted: 05 September 2014
  •  Published: 17 September 2014

Abstract

A Nocardia seriolae was isolated from diseased spotted butterfish (Scatophagus argus, Linn). The cumu-lative mortality within one month was 30% (660 out of 2200). The diseased fish were two years old with lengths from 18 to 25 cm. Most fish suffered from haemorrhages and ulcers of the skin. The most significant gross pathological change was enlargement of the spleen, kidney and liver. White nodules, varying in size, were found in these organs. The isolated bacteria were either coccoid or filamentous in appearance, with bead-like staining. The identification of NS128 was verified by polymerase chain reaction (PCR) assay for N. seriolae that gave the expected specific amplicon of 432 bp of the 16S rDNA sequence with a 100% sequence identity with N. seriolae (GenBank accession number AF380937). A partial sequence of the 16S rRNA gene (GenBank accession number EU147501), the RNA polymerase B subunit (rpo B) gene (GenBank accession number DQ119300) and the heat shock protein gene (GenBank accession number DQ431437) of the organism, NS128 and the type strain of N. seriolae BCRC 13745 formed a monophyletic clade with a high sequence similarity and a bootstrap of 100%. White nodules that were induced in experimental fish, spotted butterfish and amberjack (Seriola dumerili, Risso) were similar to those in naturally infected fish cases and N. seriolae were re-isolated using brain heart infusion agar. These finding provides evidence that N. seriolae caused systemic granulomas in spotted butterfish. Based on the growth characteristics, and biochemical properties of the bacterium, its histopathological changes, PCR and the phylogenetic analysis, the pathogenic organism was identified as N. seriolae. This investigation is the first published on N. seriolae infection in spotted butterfish in aquaculture. The results reveal that the N. seriolae isolated in the field was pathogenic to spotted butterfish and amberjack.

Key words: Pathogenicity, Nocardia seriolae, spotted butterfish, Scatophagus argus, polymerase chain reaction (PCR).

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This article is published under the terms of the Creative Commons Attribution License 4.0

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