title: Biotransformation of the antibiotic agent flumequine by ligninolytic fungi and residual antibacterial activity of the transformation mixtures.
abstract: Flumequine, a fluoroquinolone antibiotic, is applied preferably in veterinary medicine, for stock breeding and treatment of aquacultures. Formation of drug resistance is a matter of general concern when antibiotics such as flumquine occur in the environment. Thus, biodegradation of flumequine in solution was investigated using five different ligninolytic fungi. Irpex lacteus, Dichomitus squalens, and Trametes versicolor proved most efficient and transformed more than 90% of flumequine within 6 or even 3 days. Panus tigrinus and Pleurotus ostreatus required up to 14 days to remove >90% of flumequine. Analyses of the metabolites by liquid chromatography-mass spectrometry suggest different transformation pathways for the different fungal strains. Structure proposals were elaborated for 8 metabolites. 7-Hydroxy-flumequine and flumequine ethyl ester were identified as common metabolites produced by all ligninolytic fungi. The largest variety of metabolites was formed by D. squalens. Residual antibacterial activity of the metabolite mixtures was tested using gram-positive and gram-negative bacteria. While for the less efficient P. tigrinus and P. ostreatus cultures the antibacterial activities corresponded to the residual concentrations of flumequine, a remarkable antibacterial activity remained in the D. squalens cultures although flumequine was transformed to more than 90%. Obviously, antibacterially active transformation products were formed by this fungal strain.
authors.affiliation: Institute of Microbiology , Academy of Sciences of the Czech Republic, v.v.i., Vídeňská 1083, CZ-142 20 Prague 4, Cech Republic.
authors.forename: Monika
authors.initials: M
authors.lastname: Cvančarová
authors.forename: Monika
authors.initials: M
authors.lastname: Moeder
authors.forename: Alena
authors.initials: A
authors.lastname: Filipová
authors.forename: Thorsten
authors.initials: T
authors.lastname: Reemtsma
authors.forename: Tomáš
authors.initials: T
authors.lastname: Cajthaml
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001673:Biodegradation, Environmental / Q000187:drug effects; D001711:Biotransformation / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media / Q000737:chemistry; D024841:Fluoroquinolones / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D005658:Fungi / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism*; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D020076:Pleurotus / Q000378:metabolism; D025341:Principal Component Analysis; D055454:Trametes / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D024841:Fluoroquinolones; D008031:Lignin; C012976:flumequine