ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Food Microbiology
This article is part of the Research TopicFood Safety in the Context of One Health: Current Trends, Challenges and PerspectivesView all 12 articles
Impact of treated wastewater reuse in agriculture on the transfer of antimicrobial-resistant bacteria and genes to edible crops: A One Health perspective
Provisionally accepted
Anicia Gomes1
Jesús López-Cañizares2
Alberto Martinez-Alonso2
Macarena Moreno2
ANA ALLENDE2,3
Pilar Truchado Gambao2*- 1REQUIMTE LAQV Porto, Porto, Portugal
- 2Centro de Edafologia y Biologia Aplicada del Segura, Murcia, Spain
- 3Spanish National Research Council (CSIC), Madrid, Spain
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The use of reclaimed water for irrigating fresh produce is increasing as a sustainable water management strategy. However, this practice may pose public health risks by promoting the dissemination of antibiotic-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs). This study evaluated whether irrigation with treated wastewater of different microbiological quality (secondary-and tertiary-treated wastewater) contributes to the transmission of antibiotic-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) from irrigation water to lettuce plants, using potable water as control. This study evaluated whether irrigation with treated wastewater of different microbiological quality influences the abundance of bacteria and resistance genes in lettuce plants compared with irrigation using potable water. Bacterial indicators (Escherichia coli and, extended-spectrum β-lactamase-producing E. coli, ESBL-E. coli) and ARGs (blaCTX-M-1, blaTEM, sul1, tetA) were quantified in irrigation water and lettuce using culture-based methods and quantitative PCR (qPCR). In addition, the efficiency of tertiary treatment in reducing Escherichia coli, extended-spectrum β-lactamase-producing E. coli (ESBL-E. coli), and resistance genes in reclaimed water was assessed. The relative abundance of ARGs was normalized to the 16S rRNA gene to evaluate potential amplification or persistence of resistance during water reuse and irrigation. Results showed that E. coli and ESBL-E. coli were consistently detected in crops irrigated with secondary-treated water but remained below detection limits after irrigation withusing tertiary treatedtertiary-treated and potable water. Resistance gene profiles followed a similar trend: secondary-treated water contained the highest absolute and relative abundances of blaCTX-M-1, blaTEM, sul1, and tetA, while tertiary treatment substantially reduced but did not completely eliminate them. In lettuce, ARG levels on lettuce were substantially lower than in the corresponding irrigation waters, representing only 4% and 6% of the
Keywords: antimicrobial resistance, Environmental surveillance, fresh produce, Irrigation water, qPCR, sustainable agriculture, wastewater, Water reuse
Received: 21 Oct 2025; Accepted: 09 Dec 2025.
Copyright: © 2025 Gomes, López-Cañizares, Martinez-Alonso, Moreno, ALLENDE and Truchado Gambao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Pilar Truchado Gambao
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