title: Antimicrobial activity and acute toxicity of ozonated lomefloxacin solution.
abstract: Lomefloxacin (LOM) is a synthetic antimicrobial from the fluoroquinolone family (FQ) used as a veterinary and human drug. Once in the environment, LOM may pose a risk to aquatic and terrestrial microorganisms due to its antimicrobial activity. This study evaluated the effect of ozonation of LOM (500 μg L-1), the residual antimicrobial activity against Escherichia coli and acute toxicity against Vibrio fischeri. In addition, degradation products were investigated by UHPLC-MS/MS and proposed. Ozonation was carried out varying the applied ozone dose from 0 to 54.0 mg L-1O3and pH values of 3, 7, and 11. Ozonation was most efficient at pH 11 and led to 92.8% abatement of LOM in a 9-min reaction time (54.0 mg L-1O3applied ozone dose). Ozonation at pH 3 was able to degrade 80.4% of LOM. At pH 7, 74.3% of LOM was degraded. Although the LOM concentration and the antimicrobial activity of the solution dropped as ozone dose increased (antimicrobial activity reduction of 95% at pH 11), toxicity to V. fischeri increased for pH 7 and 11 (i.e., 65% at pH 7 and 75% at pH 11). The reduction in antimicrobial activity may be related to the oxidation of piperazinyl and the quinolone moiety. The formation of intermediates depended on the oxidant (hydroxyl radicals or/and molecular O3) that acted the most in the process.
authors.affiliation: School of Civil Engineering, Architecture and Urban Design, University of Campinas, P.O. Box 6143, Campinas, 13083-889, Brazil.
authors.forename: Amanda Marchi Duarte
authors.initials: AMD
authors.lastname: de Oliveira
authors.affiliation: School of Civil Engineering, Architecture and Urban Design, University of Campinas, P.O. Box 6143, Campinas, 13083-889, Brazil.
authors.forename: Milena Guedes
authors.initials: MG
authors.lastname: Maniero
authors.affiliation: Institute of Chemistry, Department of Analytical Chemistry, University of Campinas, P.O. Box 6154, Campinas, SP, 13084-971, Brazil.
authors.forename: Caio
authors.initials: C
authors.lastname: Rodrigues-Silva
authors.affiliation: School of Civil Engineering, Architecture and Urban Design, University of Campinas, P.O. Box 6143, Campinas, 13083-889, Brazil. jorober@fec.unicamp.br.
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Guimarães
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology / Q000633:toxicity; D024841:Fluoroquinolones / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity*; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry*; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity*
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D012996:Solutions; D014874:Water Pollutants, Chemical; D017665:Hydroxyl Radical; D010126:Ozone; C053091:lomefloxacin
keywords: AOP; Biological assays; Fluoroquinolone; Hydroxyl radical; Microtox®; Molecular ozone