Fate of cefotaxime-resistant Enterobacteriaceae and ESBL-producers over a full-scale wastewater treatment process with UV disinfection

Disinfection by UV radiation is one of the most promising solutions to reduce the bacterial load and antibiotic resistance in the final effluents of urban wastewater treatment plants (UWTP). Our aim was to evaluate the fate of cefotaxime-resistant Enterobacteriaceae and Extended Spectrum Beta-Lactamase (ESBL) producers in a full-scale system that includes UV-C disinfection. Over treatment, the abundance of cefotaxime-resistant Enterobacteriaceae was reduced, with reductions of 1.9 log units after secondary treatment (STW samples) and 1.8 log following UV disinfection (UTW samples). These reductions, did not reflect the variations in the prevalence of cefotaxime-resistant Enterobacteriaceae, estimated to be of 3% in raw wastewater (RW), 18% in STW and 3% in UTW. A significant increase of cefotaxime-resistant bacterial counts (0.5 log; p