Sustainable water reuse in food production: risks of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and antimicrobial resistance gene release from tertiary-treated reclaimed water

Wastewater reuse for agricultural irrigation is increasingly essential, but it carries potential public health risks due to the dissemination of antimicrobial resistance (AMR). This study evaluates the effectiveness of four tertiary wastewater treatment technologies—peracetic acid (PAA), PAA combine...

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Main Authors: Pilar Truchado, Márcia Oliveira, Rebeca Cordero-García, Manuel Abellán Soler, Amador Rancaño, Francisca García, Avelino Álvarez-Ordóñez, Ana Allende
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-06-01
Series:Frontiers in Microbiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2025.1591202/full
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author Pilar Truchado
Márcia Oliveira
Rebeca Cordero-García
Manuel Abellán Soler
Amador Rancaño
Francisca García
Avelino Álvarez-Ordóñez
Ana Allende
author_facet Pilar Truchado
Márcia Oliveira
Rebeca Cordero-García
Manuel Abellán Soler
Amador Rancaño
Francisca García
Avelino Álvarez-Ordóñez
Ana Allende
author_sort Pilar Truchado
collection DOAJ
description Wastewater reuse for agricultural irrigation is increasingly essential, but it carries potential public health risks due to the dissemination of antimicrobial resistance (AMR). This study evaluates the effectiveness of four tertiary wastewater treatment technologies—peracetic acid (PAA), PAA combined with low-intensity ultraviolet-C (PAA/UV Low), high-intensity UV-C (UV High), and ultrafiltration (UF)—in reducing extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E. coli) and antimicrobial resistance genes (ARGs) in reclaimed water used for irrigation. The relative abundance of the genes, normalized to the 16S RNA gene present in the water samples, was then estimated to assess whether there is an amplification of these genes during the reuse process in the wastewater treatment plant (WWTP). The results indicate that while all treatments significantly reduced ESBL-E. coli (≥3 logs cfu/100 mL) and ARGs (≥ 1.5 logs gc/100 mL), complete elimination was not achieved in any WWTP. Among the treatments, UF demonstrated the highest removal efficiency (≈4 log gc ARG/100 mL), against ARGs, followed by UV High (≈3 log gc ARG/100 mL), whereas PAA and PAA/UV Low were less effective (≈2 log gc ARG/100 mL). The study also found that while absolute ARG levels were reduced, their relative abundance remained stable or showed minimal decline, suggesting a persistent environmental reservoir of resistance genes. Among the ARGs analyzed, the most frequently detected were associated with tetracyclines (tetW, tetA), quinolones (qnrB, qnrS), and sulfonamides (sul1, sul2), highlighting potential public health concerns. Moreover, multidrug-resistant (MDR) ESBL-E. coli isolates were present across all WWTPs, exhibiting resistance to β-lactams, quinolones, tetracyclines, and sulfonamides. Nevertheless, notably low levels of resistance to last-resort antibiotics (tigecycline, colistin, and meropenem) were observed. These findings underscore the critical role of tertiary treatments in mitigating antimicrobial resistance (AMR) risks in water reuse systems. However, the persistence of ARGs in effluents suggests that current WWTP processes require further optimization.
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spelling doaj-art-980cd1fa84cb4fbc8c831cd856af08982025-08-20T02:36:02ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2025-06-011610.3389/fmicb.2025.15912021591202Sustainable water reuse in food production: risks of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and antimicrobial resistance gene release from tertiary-treated reclaimed waterPilar Truchado0Márcia Oliveira1Rebeca Cordero-García2Manuel Abellán Soler3Amador Rancaño4Francisca García5Avelino Álvarez-Ordóñez6Ana Allende7Research Group on Microbiology and Quality of Fruit and Vegetables, Food Science and Technology Department, CEBAS-CSIC, Murcia, SpainDepartment of Food Hygiene and Technology and Institute of Food Science and Technology, Universidad de León, León, SpainDepartment of Food Hygiene and Technology and Institute of Food Science and Technology, Universidad de León, León, SpainEntidad Regional de Saneamiento y Depuración de Murcia (ESAMUR), Murcia, SpainAcciona Agua, S.A.U., Madrid, SpainAcciona Agua, S.A.U., Madrid, SpainDepartment of Food Hygiene and Technology and Institute of Food Science and Technology, Universidad de León, León, SpainResearch Group on Microbiology and Quality of Fruit and Vegetables, Food Science and Technology Department, CEBAS-CSIC, Murcia, SpainWastewater reuse for agricultural irrigation is increasingly essential, but it carries potential public health risks due to the dissemination of antimicrobial resistance (AMR). This study evaluates the effectiveness of four tertiary wastewater treatment technologies—peracetic acid (PAA), PAA combined with low-intensity ultraviolet-C (PAA/UV Low), high-intensity UV-C (UV High), and ultrafiltration (UF)—in reducing extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E. coli) and antimicrobial resistance genes (ARGs) in reclaimed water used for irrigation. The relative abundance of the genes, normalized to the 16S RNA gene present in the water samples, was then estimated to assess whether there is an amplification of these genes during the reuse process in the wastewater treatment plant (WWTP). The results indicate that while all treatments significantly reduced ESBL-E. coli (≥3 logs cfu/100 mL) and ARGs (≥ 1.5 logs gc/100 mL), complete elimination was not achieved in any WWTP. Among the treatments, UF demonstrated the highest removal efficiency (≈4 log gc ARG/100 mL), against ARGs, followed by UV High (≈3 log gc ARG/100 mL), whereas PAA and PAA/UV Low were less effective (≈2 log gc ARG/100 mL). The study also found that while absolute ARG levels were reduced, their relative abundance remained stable or showed minimal decline, suggesting a persistent environmental reservoir of resistance genes. Among the ARGs analyzed, the most frequently detected were associated with tetracyclines (tetW, tetA), quinolones (qnrB, qnrS), and sulfonamides (sul1, sul2), highlighting potential public health concerns. Moreover, multidrug-resistant (MDR) ESBL-E. coli isolates were present across all WWTPs, exhibiting resistance to β-lactams, quinolones, tetracyclines, and sulfonamides. Nevertheless, notably low levels of resistance to last-resort antibiotics (tigecycline, colistin, and meropenem) were observed. These findings underscore the critical role of tertiary treatments in mitigating antimicrobial resistance (AMR) risks in water reuse systems. However, the persistence of ARGs in effluents suggests that current WWTP processes require further optimization.https://www.frontiersin.org/articles/10.3389/fmicb.2025.1591202/fullwastewater treatmentsustainable agricultureESBL-E. coliantimicrobial resistance (AMR)irrigation water
spellingShingle Pilar Truchado
Márcia Oliveira
Rebeca Cordero-García
Manuel Abellán Soler
Amador Rancaño
Francisca García
Avelino Álvarez-Ordóñez
Ana Allende
Sustainable water reuse in food production: risks of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and antimicrobial resistance gene release from tertiary-treated reclaimed water
Frontiers in Microbiology
wastewater treatment
sustainable agriculture
ESBL-E. coli
antimicrobial resistance (AMR)
irrigation water
title Sustainable water reuse in food production: risks of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and antimicrobial resistance gene release from tertiary-treated reclaimed water
title_full Sustainable water reuse in food production: risks of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and antimicrobial resistance gene release from tertiary-treated reclaimed water
title_fullStr Sustainable water reuse in food production: risks of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and antimicrobial resistance gene release from tertiary-treated reclaimed water
title_full_unstemmed Sustainable water reuse in food production: risks of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and antimicrobial resistance gene release from tertiary-treated reclaimed water
title_short Sustainable water reuse in food production: risks of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and antimicrobial resistance gene release from tertiary-treated reclaimed water
title_sort sustainable water reuse in food production risks of extended spectrum β lactamase esbl producing escherichia coli and antimicrobial resistance gene release from tertiary treated reclaimed water
topic wastewater treatment
sustainable agriculture
ESBL-E. coli
antimicrobial resistance (AMR)
irrigation water
url https://www.frontiersin.org/articles/10.3389/fmicb.2025.1591202/full
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