Fluoroquinolone Antibiotics in the Environment: Biodegradation Studies and Presence in Environmental Matrices


22 de outubro, 2020 | 12h00 | Webinar – Plataforma ZOOM

Resumo da apresentação:

The use of fluoroquinolone antibiotics for therapeutic, prophylactic and growth promotion applications is increasing worldwide. Due to its halogenated characteristics, ecotoxicity and persistence, a special importance is given to their occurrence in the environment. Since some fluoroquinolones have one or more stereogenic centers, they give rise to pairs of enantiomers. The pharmacological properties and toxicity of enantiomers can be very different. The stereochemistry of these compounds represents a major challenge in terms of its environmental monitoring and is frequently ignored. The presence of fluoroquinolones has been described in many environmental matrices, but few studies were done in Portugal regarding environmental monitoring studies.
Degradative processes for the removal of fluoroquinolones have also been subject of several studies, but none has considered the relevance of the stereochemistry. This work comprises the development of new analytical methods using liquid chromatography with fluorescence detection (LC-FD) to assess biodegradation of chiral and achiral fluoroquinolone antibiotics and liquid chromatography tandem mass spectrometry (LCMS/MS) to quantify fluoroquinolones residues in different environmental matrices, such as influents and effluents of waste water treatment plants. As the metabolites/degradation products originated during degradation processes may present higher ecotoxicity than the parent compound this work also aimed to identify the most important by-products originated during these processes. Fluoroquinolones by-products formed during degradation assays were identified using an integrated analytical approach and these studies enabled the proposal of the chemical structures of two new metabolites for ofloxacin and norfloxacin, never reported before. Biodegradation of chiral fluoroquinolone antibiotics in laboratory experiments using activated sludge and two single bacterial strains were followed by the enantioselective methods developed. An analytical method for quantification and achiral assessment of fluoroquinolones in environmental matrices was developed and applied to wastewater treatment plants influents and effluents.

Alexandra S. Maia graduated in Environmental Health and Biotoxicology in 2009 at Instituto Universitário de Ciências da Saúde (IUCS). In 2011, she obtained the Master degree in Environmental Contamination and Toxicology at ICBAS - University of Porto, and she was selected for a research grant under the “FLUOROPHARMA” project, at the associate laboratory CBQF (Centre of Biotechnology and Fine Chemistry) from Catholic University of Portugal (UCP). In 2018, she concluded her PhD degree in Biotechnology (specialization in Environmental Science and Engineering), in the area of Environmental Analytical Chemistry. She has published 21 peer-reviewed journal papers, five of which as the first author, and has 29 conference proceedings. In February of 2019, she was selected as a junior researcher at the Laboratory of Catalysis and Materials (LCM), Faculdade de Engenharia da Universidade do Porto, under the project SAMPREP, under the supervision of Dr. Ana Rita Ribeiro. Since March 2020 she is a full-time assistant professor at IUCS (Instituto Superior de Ciências da Saúde). Current Research Interests: Development of LC-MS/MS methods for the determination of organic micropollutants; Occurrence studies of multi-class compounds in the environment; Development of novel eco-friendly sample preparation methodologies; Identification of by-products in environmental matrices.


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IINFACTS - Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde CBAS_4Ed. - Programa Doutoral em Ciências Biológicas Aplicadas à Saúde do IUCS