Characterization of Third Generation Cephalosporin- and Carbapenem-Resistant Isolates from Municipal and Hospital Wastewater.

Antibiotic resistance (AR) remains one of the greatest threats to global health, and species have the potential to spread AR in the aquatic environment. The spread of resistance to antibiotics important to human health, such as third-generation cephalosporins (3GCs) and carbapenems, is of great concern. We isolated and identified 15 cefotaxime (3GC)- and 51 carbapenem-resistant spp. from untreated hospital and treated municipal wastewater in January 2020. The most common species were (58%), (17%), (11%), and (11%). Almost all isolates exhibited a multidrug-resistant phenotype and harboured a diverse plasmidome, with the plasmid replicons ColE, IncU, and IncR being the most frequently detected. The most prevalent carbapenemase gene was the plasmid-associated and, for the first time, the , and genes were identified in spp. Among the 3GC-resistant isolates, the and genes were the most prevalent. Of the 10 isolates examined, three were capable of transferring carbapenem resistance to susceptible recipient . Our results suggest that conventionally treated municipal and untreated hospital wastewater is a reservoir for 3GC- and carbapenem-resistant, potentially harmful spp. that can be introduced into aquatic systems and pose a threat to both the environment and public health.