Seasonal and environmental drivers of antibiotic resistance and virulence in Escherichia coli from aquaculture and their public health implications

Abstract Aquaculture is increasingly impacted by environmental stressors such as temperature and pH fluctuations, which influence the proliferation and antibiotic resistance of Escherichia coli (E. coli). This study investigates the effects of these factors on the prevalence, virulence, and antibiot...

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Main Authors: Aya El Badawy, Dalia Hamza, Zeinab Ahmed, Maha A. Sabry
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-98498-8
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author Aya El Badawy
Dalia Hamza
Zeinab Ahmed
Maha A. Sabry
author_facet Aya El Badawy
Dalia Hamza
Zeinab Ahmed
Maha A. Sabry
author_sort Aya El Badawy
collection DOAJ
description Abstract Aquaculture is increasingly impacted by environmental stressors such as temperature and pH fluctuations, which influence the proliferation and antibiotic resistance of Escherichia coli (E. coli). This study investigates the effects of these factors on the prevalence, virulence, and antibiotic resistance of E. coli isolated from aquaculture environments in Egypt, with a focus on public health implications. A total of 328 Oreochromis niloticus (Nile tilapia) samples were collected from Egyptian fish farms over five sampling periods, representing different seasonal conditions. E. coli was isolated and identified using selective culture methods and biochemical tests. Molecular characterization was conducted via polymerase chain reaction (PCR) to detect diarrheagenic E. coli pathotypes (st, lt, eaeA, bfpA, stx1, stx2). Additionally, PCR was utilized to screen for β-lactamase and carbapenemase resistance genes. Water parameters, including temperature and pH, were recorded, and their correlation with bacterial prevalence, virulence, and antibiotic resistance profiles were analyzed. A high prevalence of E. coli (92.68%) was observed, with a significant correlation between bacterial occurrence and elevated water temperatures. Diarrheagenic E. coli was detected in 82.1% of samples, with enterotoxigenic E. coli (ETEC) being the most common pathotype. Some isolates harbored multiple virulence genes, indicating hybrid strains. Resistance genes such as bla TEM, bla CTX-M, and bla OXA-48 were widely distributed, particularly during warmer months and at neutral pH levels. Groups with elevated water temperatures exhibited a higher prevalence of antibiotic-resistant isolates, often harboring multiple resistance genes. This study highlights the significant role of environmental stressors in influencing the prevalence, pathogenicity, and antibiotic resistance profiles of E. coli in aquaculture systems. The findings emphasize the need for continuous monitoring and improved biosecurity measures to mitigate the risks associated with MDR E. coli in aquaculture, ensuring food safety and protecting public health.
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spelling doaj-art-ccd948933e3f4a0e9b3442b678a8be382025-08-20T01:49:42ZengNature PortfolioScientific Reports2045-23222025-05-0115111210.1038/s41598-025-98498-8Seasonal and environmental drivers of antibiotic resistance and virulence in Escherichia coli from aquaculture and their public health implicationsAya El Badawy0Dalia Hamza1Zeinab Ahmed2Maha A. Sabry3Department of Zoonoses, Faculty of Veterinary Medicine, Cairo UniversityDepartment of Zoonoses, Faculty of Veterinary Medicine, Cairo UniversityDepartment of Zoonoses, Faculty of Veterinary Medicine, Cairo UniversityDepartment of Zoonoses, Faculty of Veterinary Medicine, Cairo UniversityAbstract Aquaculture is increasingly impacted by environmental stressors such as temperature and pH fluctuations, which influence the proliferation and antibiotic resistance of Escherichia coli (E. coli). This study investigates the effects of these factors on the prevalence, virulence, and antibiotic resistance of E. coli isolated from aquaculture environments in Egypt, with a focus on public health implications. A total of 328 Oreochromis niloticus (Nile tilapia) samples were collected from Egyptian fish farms over five sampling periods, representing different seasonal conditions. E. coli was isolated and identified using selective culture methods and biochemical tests. Molecular characterization was conducted via polymerase chain reaction (PCR) to detect diarrheagenic E. coli pathotypes (st, lt, eaeA, bfpA, stx1, stx2). Additionally, PCR was utilized to screen for β-lactamase and carbapenemase resistance genes. Water parameters, including temperature and pH, were recorded, and their correlation with bacterial prevalence, virulence, and antibiotic resistance profiles were analyzed. A high prevalence of E. coli (92.68%) was observed, with a significant correlation between bacterial occurrence and elevated water temperatures. Diarrheagenic E. coli was detected in 82.1% of samples, with enterotoxigenic E. coli (ETEC) being the most common pathotype. Some isolates harbored multiple virulence genes, indicating hybrid strains. Resistance genes such as bla TEM, bla CTX-M, and bla OXA-48 were widely distributed, particularly during warmer months and at neutral pH levels. Groups with elevated water temperatures exhibited a higher prevalence of antibiotic-resistant isolates, often harboring multiple resistance genes. This study highlights the significant role of environmental stressors in influencing the prevalence, pathogenicity, and antibiotic resistance profiles of E. coli in aquaculture systems. The findings emphasize the need for continuous monitoring and improved biosecurity measures to mitigate the risks associated with MDR E. coli in aquaculture, ensuring food safety and protecting public health.https://doi.org/10.1038/s41598-025-98498-8Seasonal variationsE. coliVirulence genesAntibiotic resistance genesFish farmsEgypt
spellingShingle Aya El Badawy
Dalia Hamza
Zeinab Ahmed
Maha A. Sabry
Seasonal and environmental drivers of antibiotic resistance and virulence in Escherichia coli from aquaculture and their public health implications
Scientific Reports
Seasonal variations
E. coli
Virulence genes
Antibiotic resistance genes
Fish farms
Egypt
title Seasonal and environmental drivers of antibiotic resistance and virulence in Escherichia coli from aquaculture and their public health implications
title_full Seasonal and environmental drivers of antibiotic resistance and virulence in Escherichia coli from aquaculture and their public health implications
title_fullStr Seasonal and environmental drivers of antibiotic resistance and virulence in Escherichia coli from aquaculture and their public health implications
title_full_unstemmed Seasonal and environmental drivers of antibiotic resistance and virulence in Escherichia coli from aquaculture and their public health implications
title_short Seasonal and environmental drivers of antibiotic resistance and virulence in Escherichia coli from aquaculture and their public health implications
title_sort seasonal and environmental drivers of antibiotic resistance and virulence in escherichia coli from aquaculture and their public health implications
topic Seasonal variations
E. coli
Virulence genes
Antibiotic resistance genes
Fish farms
Egypt
url https://doi.org/10.1038/s41598-025-98498-8
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