Crop irrigation with reclaimed water have resulted in increased levels of antibiotics, antibiotic resistant bacteria (ARB) and genes (ARGs) in agroecosystems. Vegetable microbiomes are important to the quality and safety of fresh produce and could be influenced by crop production with contaminated soils and waters. However, little is known about how exposure to antibiotics influence the ARB, ARGs and microbiomes, and whether the changes of microbiomes influence the survival of human pathogens in soils and vegetables. This study investigated the Salmonella survival on lettuce irrigated with antibiotics-spiked irrigation water using culture-dependent isolation method. ARGs and microbiomes in lettuce were examined using high throughput real-time qPCR and 16S rRNA sequencing. Salmonella survival was not influenced by the uptake and accumulation of antibiotics in lettuce leaves. Ongoing work is examining the antibiotics concentrations, ARGs profile, and bacterial communities in bulk soil, rhizosphere soil, lettuce roots, and lettuce shoots. Multivariate analysis will be performed to link antibiotics concentrations, microbiome, and ARGs in soils and lettuce. These results will improve our understanding on risks associated with vegetable production using reclaimed water, thus minimizing environmental risks of water reuse in agriculture.

Antibiotic resistance genes, microbiomes, and Salmonella survival in lettuce exposed to antibiotics via soil surface irrigation

2019 Fall National Meeting

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