Occurrence of antibiotics and antibiotic resistance genes in hospital and urban wastewaters and their impact on the receiving river. (1st February 2015)

• Record Type: Journal Article
• Authors: Rodriguez-Mozaz, Sara; Chamorro, Sara; Marti, Elisabet; Huerta, Belinda; Gros, Meritxell; Sànchez-Melsió, Alexandre; Borrego, Carles M.; Barceló, Damià; Balcázar, Jose Luis
• Is Part Of: Water research. Volume 69(2015)
• Page Start: 234
• Page End: 242
• Publication Date: 2015-02-01
• Subjects: Urban and hospital wastewater -- Antibiotics -- Antibiotic resistance -- Aquatic ecosystem; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2014.11.021
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Antibiotic resistance has become a major health concern; thus, there is a growing interest in exploring the occurrence of antibiotic resistance genes (ARGs) in the environment as well as the factors that contribute to their emergence. Aquatic ecosystems provide an ideal setting for the acquisition and spread of ARGs due to the continuous pollution by antimicrobial compounds derived from anthropogenic activities. We investigated, therefore, the pollution level of a broad range of antibiotics and ARGs released from hospital and urban wastewaters, their removal through a wastewater treatment plant (WWTP) and their presence in the receiving river. Several antimicrobial compounds were detected in all water samples collected. Among antibiotic families, fluoroquinolones were detected at the highest concentration, especially in hospital effluent samples. Although good removal efficiency by treatment processes was observed for several antimicrobial compounds, most antibiotics were still present in WWTP effluents. The results also revealed that copy numbers of ARGs, such as bla TEM (resistance to β-lactams), qnrS (reduced susceptibility to fluoroquinolones), ermB (resistance to macrolides), sul I (resistance to sulfonamides) and tet W (resistance to tetracyclines), were detected at the highest concentrations in hospital effluent and WWTP influent samples. Although there was a significant reduction in copy numbers of these ARGs in WWTP effluent samples, this reduction was not uniform across analyzed ARGs. Relative concentration of ermB and tetW genes decreased as a result of wastewater treatment, whereas increased in the case of bla TEM, sul I and qnrS genes. The incomplete removal of antibiotics and ARGs in WWTP severely affected the receiving river, where both types of emerging pollutants were found at higher concentration in downstream waters than in samples collected upstream from the discharge point. Taken together, our findings demonstrate a widespread occurrence of antibiotics and ARGs in urban and hospital wastewater and how these effluents, even after treatment, contribute to the spread of these emerging pollutants in the aquatic environment. Highlights: Antibiotics and ARGs studied in a hospital-urban wastewater system and receiving river. Higher levels of fluoroquinolones were found in hospital than in urban wastewater. Similar levels of ARGs were found in hospital and urban wastewaters. Urban treated effluents contribute to antibiotic pollution and resistance in the aquatic environment. Correlations between antibiotic concentration and corresponding ARG were observed.