Go to main content

The Bergen sewage: 1,580 antibiotic-resistant bacteria identified


A scientist in a lab, holding a petridish with samples.

Researcher Nachiket Marathe is in charge of the project that has taken samples from the sewage in Bergen.

Photo: Priyank Nimje

IMR researchers have discovered a new type of antibiotic-resistant E. coli bacterium. This adds to a long list of similar findings in Bergen's sewage.

“This E. coli type has never been seen anywhere in the world before, but now we’ve found it in Bergen.”

That’s what marine researcher Nachiket Marathe says about the new type of antibiotic-resistant E. coli bacterium discovered by him and his research colleagues in Bergen's sewage.

The discovery is described in a recent scientific article published in the Journal of Global Antimicrobial Resistance.

Samples from 2020 to 2023

Between 2020 and 2023, researchers from the Institute of Marine Research (IMR) regularly collected sewage samples from five different treatment plants in Bergen.

Over those years, the researchers identified 1,580 different bacteria resistant to at least one type of antibiotic.

Could kill 39 million by 2050

Antibiotic-resistant bacteria are a major global issue. A recent study in The Lancet estimates that such bacteria could cause 39 million deaths by 2050.

“Currently, antibiotic resistance is monitored in Norwegian hospitals, but we also need systematic surveillance in the environment and the general population,” Marathe says.

A new EU regulation also suggests monitoring disease-causing bacteria and viruses, as well as resistance, in sewage.

Poop from Bergen

When the Institute of Marine Research collected sewage samples between 2020 and 2023, they sampled both untreated sewage and treated wastewater.

“The advantage of this approach is that the raw sewage data tells us what exists in the population, while the treated wastewater data indicates what is being released into the environment and the ocean,” Marathe explains.

The five treatment plants cover different areas of Bergen. One plant processes all sewage from the city’s hospitals, while another handles sewage from the airport and cruise port. The remaining three plants mainly serve the general population.

“This means we have more data on bacteria and antibiotic resistance in sewage than anyone else in Norway,” the marine researcher says.

Grå hall med rekkverk og stort basseng med brunaktig væske i midten.
Kvernevik treatment plant is one of the plants from where IMR researchers have collected sewage samples from. (Photo: Gunn Eklund Breisnes / Bergen kommune)

Hospital bacteria entering the ocean

When researchers examined which bacteria were recurring at the various plants, they noticed something interesting.

“We observed that some E. coli strains resistant to the antibiotic carbapenem were consistently detected only in the sewage from the plant receiving hospital waste – in both raw and treated wastewater,” Marathe reveals.

“This indicates that hospital sewage contributes to the spread of pathogenic bacteria into the marine environment,” he adds.

Reference

Grevskott, Didrik H., F. Salvà-Serra, E. R. B. Moore og N. P. Marathe. «Escherichia coli novel sequence type 11873 harbours a new CTX-M-15–carrying multidrug resistance type 1/2 hybrid IncC plasmid». Journal of Global Antimicrobial Resistance (2024). Link: https://doi.org/10.1016/j.jgar.2024.08.008