Occurrence and distribution of Antibiotics and Antibiotic-Resistant Bacteria in theSuquía River (Córdoba, Argentina)

VALDÉS, MARÍA EUGENIA; RUIZ, SUSANA EUGENIA; SANTOS, LÚCIA HELENA ; BARCUDI DANILO; RODRÍGUEZ CASTRO, CAROLINA; GIORGI, ADONIS; WUNDERLIN, DANIEL ALBERTO; BARCELÓ, DAMIA; SOLA CLAUDIA; SAKA HECTOR A; RODRÍGUEZ-MOZAZ, SARA; AMÉ, MARÍA VALERIA

Toronto

Congreso; Society of Environmental Toxicology and Chemistry North America 40 th Annual Meeting; 2019

Society of Environmental Toxicology and Chemistry

Antibiotics (AB) are a particular group of emerging contaminants that have gained a lot of attention because of their high consumption in human and veterinary medicine, worldwide distribution in the environment and association with the proliferation of antibiotic resistance bacteria (ARB) bearing clinically relevant antibiotic resistance genes (ARG). The aim of this study was to evaluate the presence and environmental distribution of AB in the urban area of Suquía River (Córdoba city-1,330,023 inhabitants,Argentina) as well as ARB. Samples of water, sediment and natural river biofilms were collectedat 5sampling points: S1- control (upstream Córdoba city and the intake of water supply), S2 (dump area), S3 (downstream a city ringway), S4 and S5 (6 and 10 km downstream the city wastewater treatment plant-WWTP-discharge), during wet and dry seasons (2016). Samples were extracted by SPE, PLE and bead disruption andAB residues were determined by UPLC-MS/MS analysis:50 compounds in water, 40in biofilm and 30 in sediments.Water samples were also cultured in selective chromogenic media for detection of ARB. As a result, 12AB belonging to 8 chemical families were quantified in samples of urban influence (S2 to S5): 0.003-292 µg/Lrange of concentrationsin water,2-652 µg/kg d.w. in biofilm and 0.6-34 µg/kg d.w. in sediment. No ABwere detected in S1. S4 and S5 were the most polluted sites(highest loads and variety of AB). However, there are non-point sources of pollution in S2 and S3.Cephalexin was the most frequent AB in water samples, while fluoroquinolones (ofloxacin and ciprofloxacin) and macrolides (clarithromycin and azithromycin) were the most frequent AB in biofilm and sediments. This correlated with marked enrichment in ARB bearing clinical relevant ARGs, such us extended-spectrum producing Enterobacteriaceae and glycopeptide resistant Enterococcus. Higher AB frequencies and concentrations were detected in solid matrixes during wet season. Thiscould be related to matrixes composition: more heterotrophic communities in biofilm and higher organic carbon content insediments. The presence of AB along the urban area of Suquía river points out wastewater treatment plant discharges as main source of these compounds, while urban runoff and sewage illegal dischargesincreases the presence of AB in other areas. This study contributes to the knowledge of distribution of AB and their potential risk in urban impacted freshwater systems in Latin America.