Cefiderocol-resistant pathogens in German hospital wastewater: a reservoir for multidrug resistance

This study examined cefiderocol-resistant bacteria in wastewater from six German tertiary hospitals. From 36 samples, 97 resistant isolates were recovered, mainly Enterobacter roggenkampii, Klebsiella oxytoca, Serratia marcescens, and Citrobacter farmeri. Most showed high-level cefiderocol resistance, multidrug resistance, and frequently carried carbapenemase genes—often in combination with ESBLs and AmpC β-lactamases. All isolates remained susceptible to aztreonam-avibactam, with lower resistance observed to meropenem-vaborbactam and imipenem-relebactam. Genomic analysis revealed extensive plasmid diversity (38 types, many species-specific) and widespread biocide/heavy metal resistance genes, reflecting strong adaptation to wastewater environments. The findings underscore the role of hospital wastewater as a reservoir for multidrug-resistant pathogens and the need for ongoing resistance surveillance.