Impact of treated wastewater reuse in agriculture on the transfer of antimicrobial-resistant bacteria and genes to edible crops: a One Health perspective

The study experimentally assessed whether irrigation with secondary- and tertiary-treated wastewater facilitates transmission of antibiotic-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) to lettuce under controlled conditions, using potable water as a reference; while ARB (including E. coli and extended-spectrum β-lactamase-producing E. coli) and multiple ARGs were detectable at higher levels in secondary-treated wastewater, tertiary treatment markedly reduced their abundance and only low levels of ARGs were found on the lettuce surface, indicating limited transfer of resistance determinants to crops and highlighting that advanced wastewater treatment significantly mitigates AMR-related risks associated with reclaimed water reuse in agriculture.