Emergence of blaNDM-5 Enterobacterales in Swedish wastewater effluent

Abstract Carbapenem-resistant Enterobacterales were isolated from the outlet of a wastewater treatment plant in Kristianstad in southern Sweden, during spring and summer of the year 2024. MALDI-ToF MS identification and subsequent whole-genome sequencing identified eight Klebsiella pneumoniae strains belonging to ST437 and ST873 and 10 Escherichia coli strains belonging to ST167, ST648, ST1284, and ST8346. All strains, except K. pneumoniae ST873, were NDM-5 positive. K. pneumaniae ST437 and E. coli ST8346 carried two carbapenemase genes, bla NDM-5 and bla OXA-181, as well as the extended-spectrum-β-lactamases (ESBL) gene bla CTX-M-15. These two multi-drug-resistant ST variants that are widespread globally, that have previously not been detected in clinical settings in Sweden, are now detected in treated wastewater in a Swedish middle-sized town.