Low concentrations with high impact: Understanding the spread of antibiotic resistance in aquatic ecosystems (ANTRAQ)

• Applicant: Dr. Stefanie Heß
• Subject Area: Microbial Ecology and Applied Microbiology ; Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: from 2017 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 396445063

The fast spread of antibiotic resistance (AR) in bacteria is one of the major challenges humankind is faced with (WHO, 2014). Although a more restrictive use of antibiotics in medicine might retard or reduce the spread of AR, it is widely accepted that the environmental dimension of the problem cannot be ignored. In particular, a better understanding of the mechanisms driving persistence and proliferation of AR in environmental systems, including surface waters, is urgently needed. Several recent studies identified wastewater as one of the major pathways through which antibiotic-resistant bacteria and the respective genes are released to the aquatic environment. Besides the residues of various substances, traces of antibiotics are omnipresent in treated wastewater. Current research has produced evidence that even low concentrations of antibiotics, far below therapeutic levels, can promote the spread of resistance genes in microbial populations. However, all existing studies focused on the impact of sub-inhibitory antibiotic concentrations on single bacterial strains or artificial communities comprising just a small number of species. Consequently, the impact of low antibiotic concentrations on the microbiome and resistome of complex aquatic ecosystems remains to be uncovered. The proposed research is targeted at filling this gap of knowledge relying on the innovative method of epicPCR. For the first time, this method allows to trace the spread of AR genes in highly diverse communities at species-level. Using epicPCR, microcosms inhabited by a diverse microbial community exposed to low concentrations of antibiotics will be monitored over time in order to track changes in both the community's composition and the distribution of AR genes. The microcosm experiments are particularly suited to answer the 'hot question' of whether critical pathogenic strains can acquire AR genes under environmental conditions. The microcosm studies will be complemented by a series of batch experiments aimed to unravel the link between genomic structures and the ability of bacteria to acquire plasmid-borne AR genes.

• DFG Programme: Research Fellowships
• International Connection: Finland
• Host: Professor Teppo Hiltunen, Ph.D.