Treatment of hospital wastewater: emphasis on ecotoxicity and antibiotic resistance genesTreatment of hospital wastewater: emphasis on ecotoxicity and antibiotic resistance genes Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2025-10-312024enBACKGROUND Hospital wastewater (HWW) charges wastewater treatment plants (WWTPs) with a mixture of contaminants such as pharmaceutically active compounds (PhACs) and pathogenic bacteria. This matrix is considered highly toxic to the ecosystem and organisms, and it may induce the development of antibiotic resistant bacteria (ARB) and the transfer of antibiotic resistance genes (ARGs) within microbial communities. Conventional WWTPs cannot treat HWW effectively, because they have not been designed to confront this challenge. Therefore, this study investigated the applicability of photocatalysis to purify HWW, regarding its ecotoxicity and the removal rates of targeted substances, selected pathogenic bacteria and specific ARGs. RESULTS The HWW samples showed high toxicity towards the bioindicator Daphnia magna population, while they also contained significant levels of ARB and ARGs. Upon application of the photocatalytic treatment, the pharmaceutical concentrations decreased at a rate of >80% and the removal rates of the examined bacteria (Escherichia coli, Enterococci, Klebsiella sp. and Staphylococcus sp.) were >80%. Importantly, the bacteria remaining after photocatalysis were sensitive to the tested antibiotics. Conversely, the examined ARGs were present in high concentrations before and after photocatalytic treatment. For example, the concentrations of the selected genes, namely ampC, sul2, tetA and qnrA, in the effluents were from 104 to 106 gene copies L−1. CONCLUSIONS Photocatalysis may be a promising treatment technique for the elimination of PhACs and pathogenic bacteria from HWW. Moreover, it proved capable of altering the antibiotic resistance profile of the bacteria surviving after treatment, making them sensitive to certain antibiotic compounds. However, the main concern regarding public health protection remains, as the presence of ARGs in effluents in considerable concentrations may induce antibiotic resistance in bacterial communities of aquatic environments. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).This research has been co-financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH - CREATE - INNOVATE (project code: T2EDK-02905).http://creativecommons.org/licenses/by/4.0/Journal of Chemical Technology and Biotechnology99102129–2138Kaliakatsos_et_al_J. Chem. Technol. Biotechnol._99(10)_2024.pdfChania [Greece]Library of TUC2025-10-31application/pdf1.3 MBfree Kaliakatsos Andreas Καλιακατσος Ανδρεας Gounaki Iosifina Γουνακη Ιωσηφινα Dokianakis Spyros Maragkaki Emmanouela Stasinakis Athanasios S. Gyparakis Stylianos Katsarakis Nikos Manios Thrassyvoulos Fountoulakis Michalis S. Venieri Danai Βενιερη Δαναη Wiley Hospital wastewater Wastewater treatment Antibiotics Pharmaceuticals Antibiotic resistant bacteria Antibiotic resistance genes