Fluoroquinolones and Tetracycline Antibiotics in a Portuguese Aquaculture System and Aquatic Surroundings: Occurrence and Environmental Impact

Abstract

The growth of aquaculture over the past few years is widely recognized as one of the main sources of antibiotics, mainly fluoroquinolones (FQ) and tetracyclines (TC), in the aquatic environment, consequently, increasing the risk of the emergence of antibiotic bacterial resistance and promoting the spread of resistant genes. This study aimed to (1) develop and validate a multiresidue method for determination and quantification of ciprofloxacin (CIP), difloxacin (DIFL), enrofloxacin (ENR), norfloxacin (NOR), sarafloxacin (SARA), and oxytetracycline (OXY) in aquaculture waters and surrounding water bodies and (2) provide the first Portuguese data to utilize in assessment of risk of adverse effects. In addition, the potential environmental impact posed by these antibiotics to aquatic organisms, belonging to different trophic levels, when exposed to the studied aquaculture waters was also assessed. The analytical strategy comprised of solid-phase extraction (SPE) through Oasis HLB cartridges, and detection and quantification by liquid chromatography with tandem mass spectrometry (LC/MS(n)). Method detection limits (MDL) and method quantification limits (MQL) were in the range of 0.7-3 ng/L and 2.4-10 ng/L, respectively. Recoveries varied between 57.4 and 122.8%. The method was applied to 31 water samples collected from an aquaculture and surrounding water bodies located in north of Portugal. Residues of all antibiotics, except SARA and DIFL, were detected at concentrations ranging from 3 to 75.1 ng/L. Norfloxacin was the antibiotic present at highest frequency and concentration. Regarding the environmental impact assessment (EIA), a risk quotient higher than 1 was observed for NOR.

Oxytetracycline in intensive aquaculture: water quality during and after its administration, environmental fate, toxicity and bacterial resistance

“…For instance, OTC concentrations ranging between 9.1 and 33.3 ng L −1 were detected in a river located at 250 m downstream of an aquaculture system (Pereira et al . ). Other authors (Dietze et al .…”

Selected Pharmaceuticals in Different Aquatic Compartments: Part II—Toxicity and Environmental Risk Assessment

“…We are testing antibiotics in algae, invertebrates and fish but probably the biggest impact will be on bacteria, namely on the emergence of resistant bacteria that can reach not only aquatic animals but also humans. Additionally, the emergence of bacterial resistance is a major concern involving the presence of pharmaceuticals in the aquatic compartment, which is more prone in this environment [6,182].…”

Streptomyces Bacteria as Potential Probiotics in Aquaculture

“…These antibiotic resistance genes can be acquired by human and animal pathogens via horizontal gene transfer ( Tomova et al, 2015 ), hence leading to difficulty in the treatment of infectious diseases. Moreover, the recent evidences of residual antibiotics in the cultured organisms could pose a potential health risk to human consumers ( Chen et al, 2015 ; Pereira et al, 2015 ; Pham et al, 2015 ).…”