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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Aquatic Microbiology
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1499126

Isolation, Identification and Characteristics of Aeromonas sobria From Diseased Rainbow Trout (Oncorhynchus mykiss)

Provisionally accepted
Li-Ping Liu Li-Ping Liu 1,2Ying-Dong Fang Ying-Dong Fang 1Peng-Tian Kang Peng-Tian Kang 3Xiang-Yun Gao Xiang-Yun Gao 3Guo-Wei Zhang Guo-Wei Zhang 3Jing Pan Jing Pan 1Jia Lu Jia Lu 1Ji-Xing Liu Ji-Xing Liu 2Wang-Dong Zhang Wang-Dong Zhang 1*
  • 1 Gansu Agricultural University, Lanzhou, China
  • 2 Lanzhou Witsen Biotechnology Co., LTD, Lanzhou, China
  • 3 Gansu Fishery Technology Extension Station, Lanzhou, China

The final, formatted version of the article will be published soon.

    Aeromonas sobria is an opportunistic pathogen that can infect humans, animals and aquatic species, which is widely distributed in different aquatic environments and products. In recent years, with the rapid expansion of intensive aquaculture, the disease caused by A. sobria has occurred. This study aims to understand the pathogenic characteristics of A. sobria and provide scientific basis for the prevention and control of the epidemic. The dominant strain As012 was isolated from the diseased rainbow trout during the outbreak. Through physiological and biochemical experiments, sequencing and phylogenetic tree analysis of 16S rRNA and gyrB genes, the strain As012 was identified as A. sobria. The clinical signs of the diseased rainbow trout in the experimental infection were consistent with those in the farm, and the LD50 was 1.0×10 6.6 CFU/mL. The histopathological lesions in the gills, heart, liver, spleen and intestines were mainly extensive hemorrhage. In addition, eight virulence genes were screened from strain As012, including Act, Aer, AexT4, Alt, ahyB, ascV, Nuc and Hly. The strain As012 can grow in the environment with pH 1-11, temperature 8-43℃ and NaCl concentration 0-8%. The drug sensitivity results showed that it was resistant to 12 antibiotics including penicillin G, vancomycin, and clindamycin, and highly sensitive to 16 antibiotics including cefazolin, ciprofloxacin, and furadantin. The results showed that A. sobria, the dominant strain isolated from diseased rainbow trout, was the main pathogen causing the epidemic in the farm. The strain As012 has a very wide range of growth and strong pathogenicity, causing widespread hemorrhaging in various tissues of rainbow trout. It is multi-resistant, but . 删除[萍水相逢]: % 删除[萍水相逢]:highly sensitive to cephalosporins, quinolones, nitrofurans and sulfonamides. Among them, ciprofloxacin will be one of the effective antibiotics for preventing and controlling A. sobria infection in Chinese aquaculture.

    Keywords: 16S rRNA gene, gyrB gene, histopathology, virulence genes, Growth characteristics, Antibiotic sensitivity

    Received: 20 Sep 2024; Accepted: 03 Dec 2024.

    Copyright: © 2024 Liu, Fang, Kang, Gao, Zhang, Pan, Lu, Liu and Zhang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Wang-Dong Zhang, Gansu Agricultural University, Lanzhou, China

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