Selection of resistance
The most critical driver of antibiotic resistance evolution is likely to be a selection pressure from antibiotics.
In a series of papers published from 2007 and onwards, we revealed massive discharges from the manufacturing of bulk drugs, leading to contamination of surface, ground and drinking water to unprecedented levels. Unsurprisingly, these environments are the most extreme described on earth to date with regards to antibiotic resistance. Lower levels of antibiotics, mostly in the ng-µg/L range, reach the environment mainly through urine and feces from humans or domestic animals. Accordingly, wastewater treatment plants and impacted rivers are often claimed to be spawning grounds for resistance development. In some contrast, our own research has not pointed to selection within Swedish wastewater treatment plants. We recently provided evidence that sterile-filtered wastewater from the Sahlgrenska University Hospital strongly selects for multi-resistant E. coli (Kraupner et al, 2021), likely caused by a combination of antibiotics present therein.
We have a long history of assessing risks for resistance selection in industrially polluted environments, as well as in those polluted by human excreta, primarily sewage treatment plants. Given our recent findings of selection by hospital wastewater, we are now putting additional focus on understanding the causes for resistance selection here, both at Swedish hospitals and at hospitals abroad. We are also interested in the roles biofilms in the sewers may play.
We have a strong dedication in developing and evaluating approaches to assess the selective potential by different agents (antibiotics, biocides) and by mixtures (wastewaters). Experimental methods that accurately reflect risks for environmental selection for antibiotic resistance are needed to understand and manage various pollution sources. Field approaches that can disentangle environmental transmission from environmental selection are also important.
Examples of papers
Larsson DGJ, Flach C-F. (2021). Antibiotic resistance in the environment. Nature Reviews Microbiology. https://doi.org/10.1038/s41579-021-00649-x Read-only link: https://rdcu.be/cAQBC.
Kraupner N, Hutinel M, Schumacher K, Gray DA, Genheden M, Fick J, Flach C-F, Larsson DGJ. (2021). Evidence for selection of multi-resistant E. coli by hospital effluent. Environment international. Vol. 150:106436. https://doi.org/10.1016/j.envint.2021.106436
Kraupner N, Ebmeyer S, Hutinel M, Fick J, Flach C-F, Larsson DGJ. (2020). Selective concentrations for trimethoprim resistance in aquatic environments. Environment international. 144:106083 https://doi.org/10.1016/j.envint.2020.106083.
Rutgersson C, Ebmeyer S, Lassen SB, Karkman A, Fick J, Kristiansson K, Brandt KK, Flach C-F, Larsson DGJ. (2020). Long-term application of Swedish sewage sludge on farmland does not cause clear changes in the soil bacterial resistome. Environ Int. 137:105339. https://doi.org/10.1016/j.envint.2019.105339
Karkman A., Pärnänen K. and Larsson DGJ. (2019). Fecal pollution can explain antibiotic resistance gene abundances in anthropogenically impacted environments. Nature Commun. 80:10. DOI: https://www.nature.com/articles/s41467-018-07992-3