Widespread selection of antibiotic resistance within hospital sewers.

Hospital sewer wastewater in Sweden is linked to selection of antibiotic-resistant Escherichia coli, with ciprofloxacin and cefotaxime identified as principal selective agents.

• Why it matters: Hospital sewers may act as arenas where environmental resistance determinants are mobilized and transferred, but direct evidence for selection and its drivers has been lacking.
• What they did: Filtered wastewater from ten Swedish hospitals was used to expose Escherichia coli, showing consistent enrichment of multiple resistances versus corresponding municipal wastewaters; in-situ enrichment was also seen in sewer biofilms, with culturing and metagenomics used to compare hospital versus municipal sites.
• The result: Adding resistance genes rescued sensitive Escherichia coli under fluoroquinolones and β-lactams, and liquid-chromatography-tandem-mass-spectrometry plus thresholds implicated ciprofloxacin and cefotaxime, supporting prioritized mitigation in hospital sewers.

AI summary of the abstract · may contain errors · not medical advice · read the paper.