Quantitative study of ESBL and carbapenemase producers in wastewater treatment plants in Spain: a culture-based detection analysis of raw and treated waters [Dataset]

Abstract

Background Antibiotics could modify multidrug-resistant microorganisms (MDRO) populations in urban wastewater. Water treatment plays a major role in their control. This study aimed to explain the characteristics of multidrug-resistant Gram-negative bacteria in the wastewater of a city in southern Spain, the reduction achieved by treatment and the influence of human antibiotic prescriptions. Methods We collected 24-hour composite water samples from four wastewater treatment plants (WWTPs) over one year (2021-2022) and cultured them quantitatively. All acquired ESBL/carbapenemase isolates were sequenced and genomes were compared with those of clinical isolates. Linear mixed model regression analyses were performed to assess the WWTP effect and the association with human antibiotic prescriptions. Findings Aeromonas predominated among the MDROs and KPC-2 was the main carbapenemase detected in the influents. The 44% and 30% of E. coli and K. pneumoniae influent isolates, respectively, belonged to high-risk clones; 10·6% of Enterobacteriaceae could be matched to clinical isolates and a strain from a current hospital outbreak was found in raw samples. WWTPs reduced ESBL and carbapenemase producers by 1·4-log and 1·8-log, respectively. New MDROs and persistence of certain strains were detected in effluents. Quinolone and cephalosporin prescriptions, flow-rate and population density were associated with higher OXA-48 producer counts. Interpretation Despite the reduction, additional technologies should be implemented in WWTPs receiving hospital discharges. Due to the predominance of environmental species, culture and metagenomic approaches should be combined to differentiate human and sewages origin for antibiotic resistance monitoring. Antibiotic stewardship could be a strategy to reduce the release of MDROs.