Conjugation effects on antibiotic resistance genes at various salt Levels: Insights from single-factor and simulation study

The dissemination mechanisms of antibiotic resistance genes (ARGs) under salinity fluctuations remain poorly understood, despite their critical implications for environmental resistance ecology. This study systematically decoupled salinity-driven conjugation dynamics through controlled single-factor...

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Main Authors: Pei Jiang, Yu Xia, Jiali Chang, Cheng Zhang, Xia Li, Le Fang, Xinhui Liu
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2025-09-01
Series:Emerging Contaminants
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Online Access:http://www.sciencedirect.com/science/article/pii/S2405665025000563
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author Pei Jiang
Yu Xia
Jiali Chang
Cheng Zhang
Xia Li
Le Fang
Xinhui Liu
author_facet Pei Jiang
Yu Xia
Jiali Chang
Cheng Zhang
Xia Li
Le Fang
Xinhui Liu
author_sort Pei Jiang
collection DOAJ
description The dissemination mechanisms of antibiotic resistance genes (ARGs) under salinity fluctuations remain poorly understood, despite their critical implications for environmental resistance ecology. This study systematically decoupled salinity-driven conjugation dynamics through controlled single-factor experiments and simulated sediment microcosms. Controlled conjugation assays revealed a threshold-dependent response, with RP4 plasmid transfer frequencies peaking at 2.00 % salinity (4.58–13.51-fold increase vs. 0.85 % control, p < 0.01), mechanistically linked to reactive oxygen species (ROS)-mediated SOS pathway activation. In simulated sediment systems, salinity gradients drove host-specific ARGs enrichment, with plasmid-borne tetA and blaTEM abundances increasing 1.49–4.39 fold under brackish conditions (2.00 % salinity). Multidrug resistance genes floR, qacH-01 exhibited synergistic diffusion patterns (r = 0.77–0.94, p < 0.05), while salt-tolerant phyla Campylobacterota and Spirochaetota became dominant ARGs reservoirs at 3.50 % salinity (2.05–3.17 fold enrichment vs. controls). Although exogenous antibiotic resistance bacteria (ARB) introduction marginally reduced α-diversity, phylum-level community structure remained stable. Salinity preferentially suppressed rare taxa, amplifying ARGs co-occurrence networks through niche restructuring. These findings establish salinity as a dual regulator of ARGs dissemination, directly enhancing conjugation via oxidative stress pathways and indirectly reshaping resistance landscapes through microbial host selection. The results underscore the necessity of integrating salinity gradients into ARGs risk assessments, particularly in coastal ecosystems where tidal fluctuations may potentiate resistance propagation.
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institution Kabale University
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publishDate 2025-09-01
publisher KeAi Communications Co., Ltd.
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series Emerging Contaminants
spelling doaj-art-704516e7c6b545b0af24fef1bea356502025-08-20T03:46:49ZengKeAi Communications Co., Ltd.Emerging Contaminants2405-66502025-09-0111310052210.1016/j.emcon.2025.100522Conjugation effects on antibiotic resistance genes at various salt Levels: Insights from single-factor and simulation studyPei Jiang0Yu Xia1Jiali Chang2Cheng Zhang3Xia Li4Le Fang5Xinhui Liu6Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, 519087, China; School of Environment, Beijing Normal University, Beijing, 100875, China; Key Laboratory of Coastal Water Environmental Management and Water Ecological Restoration of Guang-dong Higher Education Institutes, Beijing Normal University, ChinaGuangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, ChinaDepartment of New Energy Materials and Chemistry, Leshan Normal University, Leshan, 614004, ChinaAdvanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai, 519087, China; Instrumentation and Service Center for Science and Technology, Beijing Normal University, Zhuhai, 519087, ChinaAdvanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, 519087, China; School of Environment, Beijing Normal University, Beijing, 100875, China; Key Laboratory of Coastal Water Environmental Management and Water Ecological Restoration of Guang-dong Higher Education Institutes, Beijing Normal University, ChinaAdvanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, 519087, China; School of Environment, Beijing Normal University, Beijing, 100875, China; Key Laboratory of Coastal Water Environmental Management and Water Ecological Restoration of Guang-dong Higher Education Institutes, Beijing Normal University, China; Corresponding author. Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, 519087, China.Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, 519087, China; School of Environment, Beijing Normal University, Beijing, 100875, China; Key Laboratory of Coastal Water Environmental Management and Water Ecological Restoration of Guang-dong Higher Education Institutes, Beijing Normal University, ChinaThe dissemination mechanisms of antibiotic resistance genes (ARGs) under salinity fluctuations remain poorly understood, despite their critical implications for environmental resistance ecology. This study systematically decoupled salinity-driven conjugation dynamics through controlled single-factor experiments and simulated sediment microcosms. Controlled conjugation assays revealed a threshold-dependent response, with RP4 plasmid transfer frequencies peaking at 2.00 % salinity (4.58–13.51-fold increase vs. 0.85 % control, p < 0.01), mechanistically linked to reactive oxygen species (ROS)-mediated SOS pathway activation. In simulated sediment systems, salinity gradients drove host-specific ARGs enrichment, with plasmid-borne tetA and blaTEM abundances increasing 1.49–4.39 fold under brackish conditions (2.00 % salinity). Multidrug resistance genes floR, qacH-01 exhibited synergistic diffusion patterns (r = 0.77–0.94, p < 0.05), while salt-tolerant phyla Campylobacterota and Spirochaetota became dominant ARGs reservoirs at 3.50 % salinity (2.05–3.17 fold enrichment vs. controls). Although exogenous antibiotic resistance bacteria (ARB) introduction marginally reduced α-diversity, phylum-level community structure remained stable. Salinity preferentially suppressed rare taxa, amplifying ARGs co-occurrence networks through niche restructuring. These findings establish salinity as a dual regulator of ARGs dissemination, directly enhancing conjugation via oxidative stress pathways and indirectly reshaping resistance landscapes through microbial host selection. The results underscore the necessity of integrating salinity gradients into ARGs risk assessments, particularly in coastal ecosystems where tidal fluctuations may potentiate resistance propagation.http://www.sciencedirect.com/science/article/pii/S2405665025000563Antibiotic resistance genes (ARGs)SalinityHorizontal gene transferConjugationMicrobial community
spellingShingle Pei Jiang
Yu Xia
Jiali Chang
Cheng Zhang
Xia Li
Le Fang
Xinhui Liu
Conjugation effects on antibiotic resistance genes at various salt Levels: Insights from single-factor and simulation study
Emerging Contaminants
Antibiotic resistance genes (ARGs)
Salinity
Horizontal gene transfer
Conjugation
Microbial community
title Conjugation effects on antibiotic resistance genes at various salt Levels: Insights from single-factor and simulation study
title_full Conjugation effects on antibiotic resistance genes at various salt Levels: Insights from single-factor and simulation study
title_fullStr Conjugation effects on antibiotic resistance genes at various salt Levels: Insights from single-factor and simulation study
title_full_unstemmed Conjugation effects on antibiotic resistance genes at various salt Levels: Insights from single-factor and simulation study
title_short Conjugation effects on antibiotic resistance genes at various salt Levels: Insights from single-factor and simulation study
title_sort conjugation effects on antibiotic resistance genes at various salt levels insights from single factor and simulation study
topic Antibiotic resistance genes (ARGs)
Salinity
Horizontal gene transfer
Conjugation
Microbial community
url http://www.sciencedirect.com/science/article/pii/S2405665025000563
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AT xiali conjugationeffectsonantibioticresistancegenesatvarioussaltlevelsinsightsfromsinglefactorandsimulationstudy
AT lefang conjugationeffectsonantibioticresistancegenesatvarioussaltlevelsinsightsfromsinglefactorandsimulationstudy
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