Presentation Information
[P02-243]Toxicity Assessment of Environmentally Relevant Cytostatic Drugs toward Model and Environmental Gram-Negative Bacteria
○Adam Grzywaczyk1, Olha Stefanyshyn2, Olimpia Wojciechowska1, Urszula Guzik3, Ewa Kaczorek1 (1. Institute of Chemical Technology and Engineering, Poznan University of Technology (Poland), 2. Institute of Animal Biology of NAAS (Ukraine), 3. Institute of Biology, Biotechnology and Environmental Protection, University of Silesia (Poland))
Keywords:
cytostatic drugs,microbial resistance
Cytostatic drugs, which are detected in hospital effluents, wastewater, and surface waters, raise concern about their possible impact on non-target aquatic organisms. However, their effects on environmental bacteria, particularly freshwater isolates, remain poorly understood. Thus, this study examines the acute response of selected Gram-negative bacteria to three cytostatic drugs relevant to environmental monitoring: cyclophosphamide, fluorouracil, and methotrexate.
The experimental model included reference strains of Escherichia coli and Pseudomonas aeruginosa, as well as environmental isolates obtained from lake water. Before microbiological analyses, the chemical purity of the collected water samples was verified using HPLC and GC-MS-based screening, confirming the suitability of the material for the isolation of native bacterial strains. The isolated lake-derived bacteria were identified as three strains of Aeromonas salmonicida and Pseudomonas species: P. mosselii, P. japonica, and P. rhodesiae.
Acute exposure experiments were first evaluated using growth curve analysis over a broad concentration range. No inhibition of bacterial growth was observed for any tested strain, even at concentrations up to 0.3 mg/mL. These findings indicate that conventional growth-based endpoints may be insufficient to capture subtle or early bacterial responses to cytostatic exposure. To extend the assessment beyond biomass formation, additional toxicity analyses based on Alamar Blue and MTT assays were performed in order to evaluate changes in metabolic activity and cell viability-related responses.
To broaden the interpretation of bacterial adaptation to cytostatic exposure, the analytical framework also includes a general assessment of cell surface-related responses, such as membrane permeability, surface hydrophobicity, zeta potential, and size distribution. These parameters are intended to support interpretation of whether exposure to cytostatic compounds induces early physicochemical changes at the cell envelope level, even in the absence of visible growth inhibition.
The results highlight the importance of combining growth-independent and physicochemical endpoints when assessing the environmental impact of pharmaceutical contaminants on aquatic microorganisms.
This work was supported by the National Science Centre, Poland, grant number 2024/53/N/NZ9/02287.
The experimental model included reference strains of Escherichia coli and Pseudomonas aeruginosa, as well as environmental isolates obtained from lake water. Before microbiological analyses, the chemical purity of the collected water samples was verified using HPLC and GC-MS-based screening, confirming the suitability of the material for the isolation of native bacterial strains. The isolated lake-derived bacteria were identified as three strains of Aeromonas salmonicida and Pseudomonas species: P. mosselii, P. japonica, and P. rhodesiae.
Acute exposure experiments were first evaluated using growth curve analysis over a broad concentration range. No inhibition of bacterial growth was observed for any tested strain, even at concentrations up to 0.3 mg/mL. These findings indicate that conventional growth-based endpoints may be insufficient to capture subtle or early bacterial responses to cytostatic exposure. To extend the assessment beyond biomass formation, additional toxicity analyses based on Alamar Blue and MTT assays were performed in order to evaluate changes in metabolic activity and cell viability-related responses.
To broaden the interpretation of bacterial adaptation to cytostatic exposure, the analytical framework also includes a general assessment of cell surface-related responses, such as membrane permeability, surface hydrophobicity, zeta potential, and size distribution. These parameters are intended to support interpretation of whether exposure to cytostatic compounds induces early physicochemical changes at the cell envelope level, even in the absence of visible growth inhibition.
The results highlight the importance of combining growth-independent and physicochemical endpoints when assessing the environmental impact of pharmaceutical contaminants on aquatic microorganisms.
This work was supported by the National Science Centre, Poland, grant number 2024/53/N/NZ9/02287.
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