Antibiotic and antibiotic-resistant gene loads in swine slurries and their digestates: Implications for their use as fertilizers in agriculture

The spread of antibiotic resistance in bacteria is a matter global concern, and the identification possible sources associated genetic elements (antibiotic genes -ARGs-, components horizontal gene transfer mechanism), becoming an urgent need. While transmission ARGs medical settings have been adequately characterized, ARG propagation agroecosystems remains insufficiently studied. Particularly crucial determination potential risks to use swine slurries related products as component organic fertilizers, increasingly used farming practice. We determined loads analysed from digestates eight farms Catalonia (NE Spain), compared results with their microbiome composition. Both were conspicuous farm wastes, levels some antibiotics exceeded currently accepted minimum inhibitory concentrations. Particularly, presence high fluoroquinolones was directly correlated prevalence qnrS1 slurry. also found evidence that bacterial taxa (Actinobacteria, Proteobacteria, Spirochaeta), parameter could be potentially modulated by processing raw slurry prior fertilizer.