title: Biotransformation of the Antibiotic Danofloxacin by Xylaria longipes Leads to an Efficient Reduction of Its Antibacterial Activity.
abstract: Fluoroquinolones are considered as critically important antibiotics. However, they are used in appreciable quantities in veterinary medicine. Liquid manure and feces can contain substantial amounts of unmetabolized antibiotics and, thus, antibiotics can enter the environment if manure is used for soil fertilization. In this study, the microbial biotransformation of the synthetic veterinary fluoroquinolone danofloxacin by the ascomycete Xylaria longipes was investigated. Fungal submerged cultures led to a regioselective and almost quantitative formation of a single metabolite within 3 days. The metabolite was unequivocally identified as danofloxacin N-oxide by high-resolution mass spectrometry and one- and two-dimensional nuclear magnetic resonance spectroscopic techniques. An oxidation of the terminal nitrogen of the substituted piperazine moiety of the substance led to a remarkable reduction of 80% of the initial antibacterial activity. Thus, fungal enzymes involved in the biotransformation process might possess the potential to reduce the entrance of antibiotics via biotransformation of these compounds.
authors.affiliation: †Institute of Food Chemistry and Food Biotechnology, Justus Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Rusch
authors.affiliation: †Institute of Food Chemistry and Food Biotechnology, Justus Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Kauschat
authors.affiliation: †Institute of Food Chemistry and Food Biotechnology, Justus Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
authors.forename: Astrid
authors.initials: A
authors.lastname: Spielmeyer
authors.affiliation: ‡Institute of Inorganic and Analytical Chemistry, Justus Liebig University Giessen, Schubertstrasse 60, 35392 Giessen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Römpp
authors.affiliation: #Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Hausmann
authors.affiliation: †Institute of Food Chemistry and Food Biotechnology, Justus Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Zorn
authors.affiliation: †Institute of Food Chemistry and Food Biotechnology, Justus Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Hamscher
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D001673:Biodegradation, Environmental; D001711:Biotransformation; D024841:Fluoroquinolones / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D013058:Mass Spectrometry; D015394:Molecular Structure; D013098:Xylariales / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; C068581:danofloxacin
keywords: N-oxidation; NMR; fluoroquinolone antibiotics; fungi; high-resolution mass spectrometry