qPCR raw data 16S rRNA gene, sul1, intI1

Animal antibiotic use contributes to antimicrobial resistance (AMR) in humans. Agricultural benefits of animal manure can be overshadowed by its role as a hotspot for antibiotic-resistant bacteria, their genes, and antibiotic residues. Of particular significance are fluoroquinolones, a class of antibiotics crucial for human health according to the World Health Organization (WHO). In Buenos Aires periuban agriculture, poultry farming administers enrofloxacin, a fluoroquinolone to the flocks via drinking water, and horticulture uses poultry litter as soil amendment. Fluoroquinolones’ fate and AMR dissemination resulting from these practices remain poorly understood. Our research addresses this gap by tracing fluoroquinolones trajectory from poultry to lettuce in circular periurban agriculture. The presence of biomarkers for AMR was also studied. In our biological model, we applied poultry litter from intensive farming as a source of fluoroquinolones to a soil with no prior history of poultry litter application. Lactuca sativa (lettuce) acts as a receptor of fluoroquinolones, representing a possible pathway for human exposure.Fresh poultry litter (FPL) was obtained and subsequently stored for six months before application as stored poultry litter (SPL) in a horticulture field experiment. The experiment included control (CRL) and manured (MPS) plots where lettuce (L) was cultivated till harvest. Enrofloxacin, was detected in FPL, while its primary metabolite, ciprofloxacin, was found in SPL. No fluoroquinolones were detected in MPS; however, L-MPS samples exhibited high ENR and CIP concentrations, providing evidence of fluoroquinolone bioaccumulation in plants. Despite soil quality improved in MPS plots compared to CTR, sul1 gene abundance was 2.60 times higher reaching a relative abundance of -3.57 Log sul1 per 16S rRNA. A smaller, but significant effect was registered for intI1. Our results suggest that, while amended plots may enhance soil quality, they may also act as hotspots for selecting bacteria carrying AMR genes, potentially contributing to AMR dissemination in the environment, increasing human health risk.