Hospital wastewater favors multi-resistant bacteria

February 16, 2021

Scientists from the University of Gothenburg, Sweden presents evidence that hospital wastewater, containing elevated levels of antibiotics, rapidly kills antibiotic-sensitive bacteria, while multi-resistant bacteria continue to grow. Hospital sewers may therefore provide conditions that promote the evolution of new forms of antibiotic resistance.

It is hardly news that hospital wastewater contains antibiotics from patients. It has been assumed that hospital sewers could be a place where multi-resistant bacteria develop and thrive due to continuous low-level antibiotic exposure. However, direct evidence for selection of resistant bacteria from this type of wastewater has been lacking, until now.

A research group at the University of Gothenburg, Sweden, led by Professor Joakim Larsson, has sampled wastewater from Sahlgrenska University Hospital in Gothenburg, and at the inlet and outlet of the local municipal treatment plant for comparison. They first removed all bacteria from the wastewaters by filtering and tested how the filtered wastewater affected bacteria in different controlled test systems in the lab.

"The results were very clear," says Joakim Larsson. "In all assay, we could see that antibiotic-sensitive bacteria were rapidly killed by the hospital wastewater, while the multi-resistant ones continued to grow. The wastewater entering the municipal treatment plant, primarily made up of wastewater from households, showed a very slight effect, while we could not see any effect of the filtered wastewater."

"It is good news that the wastewater entering the Göta Älv river is not selecting for resistant bacteria, but the strong selection by hospital wastewater is concerning," says Larsson. "Strong selection pressure that favors multi-resistant bacteria is the most important driver behind the evolution of new forms of resistance in pathogens. We now know that hospital wastewater does not only contain pathogens, it can also favor resistant bacteria."

Sweden uses very little antibiotics compared to many other countries in the world. It is therefore plausible that hospitals wastewaters from other places in the world also favor resistant bacteria, but this remains to be investigated. The researchers found some antibiotics that could explain some of the effects on bacteria, but they say that more research is needed to clarify exactly what is favoring the multi-resistant ones.

"One possible way to reduce risks could involve pre-treatment of wastewater at hospitals, something that is done in certain countries already", explains Larsson. "To find the best ways to reduce risks, including designing possible treatment measures, it is critical to first figure out which antibiotics or other antibacterial chemicals explain selection for resistance. That is something we are working on right now."
-end-
The study has been published in the scientific journal Environment International.

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 150:106436 https://www.sciencedirect.com/science/article/pii/S0160412021000611

Contact: For more information, please contact Joakim Larsson, preferably by email first: joakim.larsson@fysiologi.gu.se

Research team: Research interests - Joakim Larsson group; https://www.gu.se/en/biomedicine/about-us/department-of-infectious-diseases/joakim-larsson-group

CARe: Centre for Antibiotic Resistance Research; https://www.gu.se/en/care

University of Gothenburg

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.