Emergence of highly virulent Aeromonas dhakensis in channel catfish aquaculture: Genomic insights into pathogenicity and antimicrobial resistance

Aeromonas dhakensis has emerged as a significant pathogen in aquaculture, causing severe disease outbreaks and resulting in substantial economic losses. However, its pathogenic mechanism and virulence factors remain largely unexplored. In this study, we isolated a highly virulent strain of A. dhaken...

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Main Authors: Yuanyuan Wang, Zhengqi Feng, Wenbo Wu, Zhipeng Zhan, Jiaming Huang, Changjun Guo, Jianguo He
Format: Article
Language:English
Published: Taylor & Francis Group 2025-12-01
Series:Virulence
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Online Access:https://www.tandfonline.com/doi/10.1080/21505594.2025.2525933
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author Yuanyuan Wang
Zhengqi Feng
Wenbo Wu
Zhipeng Zhan
Jiaming Huang
Changjun Guo
Jianguo He
author_facet Yuanyuan Wang
Zhengqi Feng
Wenbo Wu
Zhipeng Zhan
Jiaming Huang
Changjun Guo
Jianguo He
author_sort Yuanyuan Wang
collection DOAJ
description Aeromonas dhakensis has emerged as a significant pathogen in aquaculture, causing severe disease outbreaks and resulting in substantial economic losses. However, its pathogenic mechanism and virulence factors remain largely unexplored. In this study, we isolated a highly virulent strain of A. dhakensis, CWH5, from a severe disease outbreak in farmed channel catfish (Ictalurus punctatus). Through comprehensive whole-genome analysis, we elucidated its pathogenicity and the genetic basis for its high virulence and multi-antimicrobial resistance in channel catfish. Experimental infections showed that CWH5 exhibited exceptional virulence, with an LD50 of (5.37 ± 0.31) ×105 CFU/fish and causing 100% mortality within 24 h at a concentration of 107 CFU/fish. Histopathological examinations revealed severe multi-organ damage, including extensive hepatocellular necrosis, gill epithelial destruction, and fin tissue deterioration. Whole-genome sequencing revealed a 4.92 Mb circular chromosome encoding sophisticated virulence mechanisms, such as complete Type III, IV, and VI secretion systems, and a vast arsenal of 60 antibiotic resistance genes across 15 drug classes. Comparative genomic analysis positioned CWH5 within the A. dhakensis clade, sharing the highest sequence similarity with A. dhakensis CIP 107,500T. The co-localization of virulence and resistance determinants within mobile genetic elements suggests the potential for horizontal gene transfer. Our work underscored the importance of A. dhakensis CWH5 as an emerging pathogen in channel catfish aquaculture, providing crucial insights into the molecular mechanisms of its exceptional virulence and implying significant implications for disease management and antimicrobial resistance surveillance in aquaculture settings.
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spelling doaj-art-53f7f2de526a4fd1992478389c27fbf32025-08-20T03:14:58ZengTaylor & Francis GroupVirulence2150-55942150-56082025-12-0116110.1080/21505594.2025.2525933Emergence of highly virulent Aeromonas dhakensis in channel catfish aquaculture: Genomic insights into pathogenicity and antimicrobial resistanceYuanyuan Wang0Zhengqi Feng1Wenbo Wu2Zhipeng Zhan3Jiaming Huang4Changjun Guo5Jianguo He6School of Life Sciences, State Key Laboratory for Biocontrol & Southern Maine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Province Key Laboratory of Aquatic Economic Animals / Guangdong Provincial Observation and Research Station for Marine Ranching of the Lingdingyang Bay, Sun Yat-sen University, Guangzhou, PR ChinaSchool of Life Sciences, State Key Laboratory for Biocontrol & Southern Maine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Province Key Laboratory of Aquatic Economic Animals / Guangdong Provincial Observation and Research Station for Marine Ranching of the Lingdingyang Bay, Sun Yat-sen University, Guangzhou, PR ChinaSchool of Life Sciences, State Key Laboratory for Biocontrol & Southern Maine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Province Key Laboratory of Aquatic Economic Animals / Guangdong Provincial Observation and Research Station for Marine Ranching of the Lingdingyang Bay, Sun Yat-sen University, Guangzhou, PR ChinaSchool of Life Sciences, State Key Laboratory for Biocontrol & Southern Maine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Province Key Laboratory of Aquatic Economic Animals / Guangdong Provincial Observation and Research Station for Marine Ranching of the Lingdingyang Bay, Sun Yat-sen University, Guangzhou, PR ChinaGuangdong Evergreen Feed Industrial Co., Ltd., Zhanjiang, ChinaSchool of Life Sciences, State Key Laboratory for Biocontrol & Southern Maine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Province Key Laboratory of Aquatic Economic Animals / Guangdong Provincial Observation and Research Station for Marine Ranching of the Lingdingyang Bay, Sun Yat-sen University, Guangzhou, PR ChinaSchool of Life Sciences, State Key Laboratory for Biocontrol & Southern Maine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Province Key Laboratory of Aquatic Economic Animals / Guangdong Provincial Observation and Research Station for Marine Ranching of the Lingdingyang Bay, Sun Yat-sen University, Guangzhou, PR ChinaAeromonas dhakensis has emerged as a significant pathogen in aquaculture, causing severe disease outbreaks and resulting in substantial economic losses. However, its pathogenic mechanism and virulence factors remain largely unexplored. In this study, we isolated a highly virulent strain of A. dhakensis, CWH5, from a severe disease outbreak in farmed channel catfish (Ictalurus punctatus). Through comprehensive whole-genome analysis, we elucidated its pathogenicity and the genetic basis for its high virulence and multi-antimicrobial resistance in channel catfish. Experimental infections showed that CWH5 exhibited exceptional virulence, with an LD50 of (5.37 ± 0.31) ×105 CFU/fish and causing 100% mortality within 24 h at a concentration of 107 CFU/fish. Histopathological examinations revealed severe multi-organ damage, including extensive hepatocellular necrosis, gill epithelial destruction, and fin tissue deterioration. Whole-genome sequencing revealed a 4.92 Mb circular chromosome encoding sophisticated virulence mechanisms, such as complete Type III, IV, and VI secretion systems, and a vast arsenal of 60 antibiotic resistance genes across 15 drug classes. Comparative genomic analysis positioned CWH5 within the A. dhakensis clade, sharing the highest sequence similarity with A. dhakensis CIP 107,500T. The co-localization of virulence and resistance determinants within mobile genetic elements suggests the potential for horizontal gene transfer. Our work underscored the importance of A. dhakensis CWH5 as an emerging pathogen in channel catfish aquaculture, providing crucial insights into the molecular mechanisms of its exceptional virulence and implying significant implications for disease management and antimicrobial resistance surveillance in aquaculture settings.https://www.tandfonline.com/doi/10.1080/21505594.2025.2525933Aeromonas dhakensischannel catfishaquaculturevirulence factorsantibiotic resistancepathogenicity
spellingShingle Yuanyuan Wang
Zhengqi Feng
Wenbo Wu
Zhipeng Zhan
Jiaming Huang
Changjun Guo
Jianguo He
Emergence of highly virulent Aeromonas dhakensis in channel catfish aquaculture: Genomic insights into pathogenicity and antimicrobial resistance
Virulence
Aeromonas dhakensis
channel catfish
aquaculture
virulence factors
antibiotic resistance
pathogenicity
title Emergence of highly virulent Aeromonas dhakensis in channel catfish aquaculture: Genomic insights into pathogenicity and antimicrobial resistance
title_full Emergence of highly virulent Aeromonas dhakensis in channel catfish aquaculture: Genomic insights into pathogenicity and antimicrobial resistance
title_fullStr Emergence of highly virulent Aeromonas dhakensis in channel catfish aquaculture: Genomic insights into pathogenicity and antimicrobial resistance
title_full_unstemmed Emergence of highly virulent Aeromonas dhakensis in channel catfish aquaculture: Genomic insights into pathogenicity and antimicrobial resistance
title_short Emergence of highly virulent Aeromonas dhakensis in channel catfish aquaculture: Genomic insights into pathogenicity and antimicrobial resistance
title_sort emergence of highly virulent aeromonas dhakensis in channel catfish aquaculture genomic insights into pathogenicity and antimicrobial resistance
topic Aeromonas dhakensis
channel catfish
aquaculture
virulence factors
antibiotic resistance
pathogenicity
url https://www.tandfonline.com/doi/10.1080/21505594.2025.2525933
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