Swedish hospital wastewater promotes antibiotic-resistant bacteria

A study conducted by researchers at the University of Gothenburg has found that wastewater from ten Swedish hospitals promotes the growth of antibiotic-resistant bacteria. The research, published in Nature Communications, examined sewer systems and wastewater across eight Swedish cities.

Researchers observed that while municipal treatment plants did not show the same effect, sewage from all ten hospitals provided a distinct advantage to resistant bacteria. The study identified specific antibiotics driving this selection, notably ciprofloxacin, as well as penicillin-like antibiotics such as cefotaxim. Additionally, resistant E. coli bacteria were found to be enriched when establishing themselves in biofilms.

Professor Joakim Larsson, Director of the Center for Antibiotic Resistance Research (CARe), noted that this represents the first direct field evidence in over 25 years linking environmental effects to pharmaceuticals excreted by humans. The findings suggest that because resistance evolution occurs within the hospital sewer systems themselves, future mitigation and purification measures should be prioritized at the hospital level rather than solely at municipal treatment sites.