Isolation of Proteus sp. Closely Related to P. Vulgaris (Vulgaris/hauseri Complex) from Ornamental Koi (Cyprinus rubrofuscus) and its Pathogenicity

Koi (Cyprinus rubrofuscus) is a world-famous ornamental fish known for its unique characteristics and economic value. This species is susceptible to various infections, leading to high mortality and morbidity rates. In this study, bacterial pathogens isolated from naturally diseased koi were identif...

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Main Authors: Crystal Lim, Jia Jing, Hung Hui, Chung, Melinda Lau, Mei Lin, Cindy Kho, Jia Yung, Leonard Lim, Whye Kit, Kristene Ling, Yong, Pei Xuan, Hew
Format: Article
Language:en
Published: Springer Nature 2026
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Online Access:http://ir.unimas.my/id/eprint/51221/1/Lim_et_al-2026-Current_Microbiology.pdf
http://ir.unimas.my/id/eprint/51221/
https://link.springer.com/article/10.1007/s00284-025-04675-3
https://doi.org/10.1007/s00284-025-04675-3
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author Crystal Lim, Jia Jing
Hung Hui, Chung
Melinda Lau, Mei Lin
Cindy Kho, Jia Yung
Leonard Lim, Whye Kit
Kristene Ling, Yong
Pei Xuan, Hew
author_facet Crystal Lim, Jia Jing
Hung Hui, Chung
Melinda Lau, Mei Lin
Cindy Kho, Jia Yung
Leonard Lim, Whye Kit
Kristene Ling, Yong
Pei Xuan, Hew
author_sort Crystal Lim, Jia Jing
building Centre for Academic Information Services (CAIS)
collection Institutional Repository
content_provider Universiti Malaysia Sarawak
content_source UNIMAS Institutional Repository
continent Asia
country Malaysia
description Koi (Cyprinus rubrofuscus) is a world-famous ornamental fish known for its unique characteristics and economic value. This species is susceptible to various infections, leading to high mortality and morbidity rates. In this study, bacterial pathogens isolated from naturally diseased koi were identified as belonging mainly to the genera Aeromonas and Proteus through comprehensive characterisation and molecular identification. Experimental infections with Proteus sp. closely related to Proteus vulgaris (vulgaris/hauseri complex) showed some clinical signs very similar to those in naturally infected koi, suggesting that Proteus sp. in this study is a possible pathogen in addition to Aeromonas, indicating a potential co-infection. The median lethal dose (LD50) for Proteus sp. was determined to be 1.7 × 108 CFU/mL, with histopathological analysis showing changes such as fusions, lymphocyte aggregation, and necrosis in the kidney and liver. The bacterium was found to be sensitive to various antibiotics, suggesting that broad-spectrum antibiotics may be effective in treating the pathogen. This study represents the isolation of Proteus sp. closely related to P. vulgaris (vulgaris/hauseri complex) from koi and provides valuable insights for the prevention and management of related disease outbreaks. The study on bacterial infections in koi fish, particularly the isolation and characterization of Aeromonas species alongside Proteus sp., highlights significant implications for koi health management. The findings underscore the pathogenicity, potential for coinfection, and the susceptibility of Proteus sp. to broad-spectrum antibiotics, providing key understanding for disease outbreak management in ornamental koi populations.
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spelling my.unimas.ir-512212026-01-12T08:22:18Z http://ir.unimas.my/id/eprint/51221/ Isolation of Proteus sp. Closely Related to P. Vulgaris (Vulgaris/hauseri Complex) from Ornamental Koi (Cyprinus rubrofuscus) and its Pathogenicity Crystal Lim, Jia Jing Hung Hui, Chung Melinda Lau, Mei Lin Cindy Kho, Jia Yung Leonard Lim, Whye Kit Kristene Ling, Yong Pei Xuan, Hew QL Zoology QR Microbiology SH Aquaculture. Fisheries. Angling Koi (Cyprinus rubrofuscus) is a world-famous ornamental fish known for its unique characteristics and economic value. This species is susceptible to various infections, leading to high mortality and morbidity rates. In this study, bacterial pathogens isolated from naturally diseased koi were identified as belonging mainly to the genera Aeromonas and Proteus through comprehensive characterisation and molecular identification. Experimental infections with Proteus sp. closely related to Proteus vulgaris (vulgaris/hauseri complex) showed some clinical signs very similar to those in naturally infected koi, suggesting that Proteus sp. in this study is a possible pathogen in addition to Aeromonas, indicating a potential co-infection. The median lethal dose (LD50) for Proteus sp. was determined to be 1.7 × 108 CFU/mL, with histopathological analysis showing changes such as fusions, lymphocyte aggregation, and necrosis in the kidney and liver. The bacterium was found to be sensitive to various antibiotics, suggesting that broad-spectrum antibiotics may be effective in treating the pathogen. This study represents the isolation of Proteus sp. closely related to P. vulgaris (vulgaris/hauseri complex) from koi and provides valuable insights for the prevention and management of related disease outbreaks. The study on bacterial infections in koi fish, particularly the isolation and characterization of Aeromonas species alongside Proteus sp., highlights significant implications for koi health management. The findings underscore the pathogenicity, potential for coinfection, and the susceptibility of Proteus sp. to broad-spectrum antibiotics, providing key understanding for disease outbreak management in ornamental koi populations. Springer Nature 2026-01 Article PeerReviewed text en http://ir.unimas.my/id/eprint/51221/1/Lim_et_al-2026-Current_Microbiology.pdf Crystal Lim, Jia Jing and Hung Hui, Chung and Melinda Lau, Mei Lin and Cindy Kho, Jia Yung and Leonard Lim, Whye Kit and Kristene Ling, Yong and Pei Xuan, Hew (2026) Isolation of Proteus sp. Closely Related to P. Vulgaris (Vulgaris/hauseri Complex) from Ornamental Koi (Cyprinus rubrofuscus) and its Pathogenicity. Current Microbiology, 83 (126). pp. 1-13. ISSN 1432-0991 https://link.springer.com/article/10.1007/s00284-025-04675-3 https://doi.org/10.1007/s00284-025-04675-3
spellingShingle QL Zoology
QR Microbiology
SH Aquaculture. Fisheries. Angling
Crystal Lim, Jia Jing
Hung Hui, Chung
Melinda Lau, Mei Lin
Cindy Kho, Jia Yung
Leonard Lim, Whye Kit
Kristene Ling, Yong
Pei Xuan, Hew
Isolation of Proteus sp. Closely Related to P. Vulgaris (Vulgaris/hauseri Complex) from Ornamental Koi (Cyprinus rubrofuscus) and its Pathogenicity
title Isolation of Proteus sp. Closely Related to P. Vulgaris (Vulgaris/hauseri Complex) from Ornamental Koi (Cyprinus rubrofuscus) and its Pathogenicity
title_full Isolation of Proteus sp. Closely Related to P. Vulgaris (Vulgaris/hauseri Complex) from Ornamental Koi (Cyprinus rubrofuscus) and its Pathogenicity
title_fullStr Isolation of Proteus sp. Closely Related to P. Vulgaris (Vulgaris/hauseri Complex) from Ornamental Koi (Cyprinus rubrofuscus) and its Pathogenicity
title_full_unstemmed Isolation of Proteus sp. Closely Related to P. Vulgaris (Vulgaris/hauseri Complex) from Ornamental Koi (Cyprinus rubrofuscus) and its Pathogenicity
title_short Isolation of Proteus sp. Closely Related to P. Vulgaris (Vulgaris/hauseri Complex) from Ornamental Koi (Cyprinus rubrofuscus) and its Pathogenicity
title_sort isolation of proteus sp. closely related to p. vulgaris (vulgaris/hauseri complex) from ornamental koi (cyprinus rubrofuscus) and its pathogenicity
topic QL Zoology
QR Microbiology
SH Aquaculture. Fisheries. Angling
url http://ir.unimas.my/id/eprint/51221/1/Lim_et_al-2026-Current_Microbiology.pdf
http://ir.unimas.my/id/eprint/51221/
https://link.springer.com/article/10.1007/s00284-025-04675-3
https://doi.org/10.1007/s00284-025-04675-3
url_provider http://ir.unimas.my/