Fate and effects of antibiotics in agricultural soils

Antibiotics comprise a wide range of structurally diverse compounds used to treat bacterial infections in humans and animals, and to prevent and control disease events in livestock production. The extensive use has already led to the development of widespread antibiotic resistance and the emergence of multiresistant pathogens that can no longer be treated with available antibiotics. Antibiotics are only partially metabolized by humans and animals and enter agricultural soils mainly via manure fertilization or wastewater irrigation.

Manure application Manure is a major source of antibiotics in agricultural soils. Once added to the soil, antibiotics interact with soil particles, are subject to microbial transformation and influence the indigenous microbial community. Existing studies on the fate and effects of antibiotics mostly focus on individual compounds while knowledge on mixtures is largely missing. This has strong implications for environmental risk assessment since the ecotoxicity of pharmaceutical mixtures can be higher than the effects of individual compounds. In addition, most studies do not take into account the spatial and temporal variability of antibiotics in hotspots of soil microbial activity. Such hotspots were shown to have a substantial effect on the fate of antibiotics, but the mechanisms behind this observation are largely unknown.

The project will combine field studies, lab‐scale experiments and in silico analyses to address:
  • the impact of long‐term manure fertilization on the soil resistome,
  • the effects of antibiotic mixtures on the fate of antibiotics and the phylogenetic distribution of ARGs and,
  • the particular role of activity hotspots in soils for antibiotic degradation and ARG development and spread.

This project is part of the PhD college "FATE".