Photochemical degradation of fluoroquinolones ciprofloxacin, enrofloxacin and norfloxacin in aqueous solution under light conditions relevant to surface waters at neutral and alkaline pH was found to proceed readily with half-lives between 0.9 and 2.7 min. The products of photochemical degradation identified by HPLC-MS included defluorinated, hydroxylated, and decarboxylated structures as well as structures with opened cyclic structures. For all of the studied substances, the reaction pathways were influenced significantly by the pH of the reaction system, with more products formed at alkaline pH than at neutral pH: the ratios of products in neutral and alkaline pH were 16/26, 9/19, 15/23 for ciprofloxacin, enrofloxacin, and norfloxacin, respectively. The structures of photoproducts and pathways of photochemical degradation are proposed. The antibacterial activities of photoproduct mixtures tested on E. coli and S. epidermidis were significantly higher in comparison to parental antibiotics in the case of both ciprofloxacin and enrofloxacin with p-values less than 0.0001 in most cases. The effect of the photoproducts was shown to be dependent on the pH value of the original antibiotic solutions before photodegradation: for ciprofloxacin, antibacterial activity against E. coli was more notably pronounced with regard to neutral pH photoproducts, while a less significant, or in one case not significant, effect of pH was observed against S. epidermidis; for norfloxacin, antibacterial activity against both E. coli and S. epidermidis was especially high with regard to alkaline pH photoproducts.

Department of Chemistry Faculty of Science University of South Bohemia České Budějovice Czech Republic

Department of Medical Biology Faculty of Science University of South Bohemia České Budějovice Czech Republic

Zobrazit více v PubMed

Ahmad I, Bano R, Musharraf SG, Sheraz MA, Ahmed S, Tahir H, ul Arfeen Q, Bhatti MS, Shad Z, Hussain SF (2015) Photodegradation of norfloxacin in aqueous and organic solvents: a kinetic study. J Photochem Photobiol A Chem 302:1–10 DOI

Babić S, Periša M, Škorić I (2013) Photomytic degradation of norfloxacin, enrofloxacin and ciprofloxacin in various aqueous media. Chemosphere 91:1635–1642 DOI

Baudry-Simner PJ, Singh A, Karlowsky JA, Hoban DJ, Zhanel GG (2012) Mechanism of reduced susceptibility to ciprofloxacin in Escherichia coli isolates from Canadian hospitals. Can J Infect Dis Med Microbiol 23(3):e60–e64 DOI

Frade VMF, Dias M, Costa Teixeira AC, Alves Palma MS (2014) Environmental contamination by fluoroquinolones. Braz J Pharm Sci 50:unpaginated DOI

Jacobs MR, Bajaksouzian S, Windau A, Appelbaum PC, Patel MV, Gupte SV, Bhagwat S, De Souza NJ, Khoradiwala HF (2004) In vitro activity of the new quinolone WCK 771 against Staphylococci. Antimicrob Agents Chemother 48:3338–3342 DOI

Kratochvíl J, Štěrba J, Lieskovská J, Langhansová H, Kuzminova A, Khalakhan I, Kylián O, Straňák V (2018a) Atibacterial effect of Cu/C:F nanocomposites deposited on PEEK substrates. Mater Lett 230:96–99 DOI

Kratochvíl J, Kahoun D, Štěrba J, Langhansová H, Lieskovská J, Fojtíková P, Hanuš J, Kousal J, Kylián O, Straňák V (2018b) Plasma pomerized C:H:N:O thin films for controlled release of antibiotic substtances. Plasma Process Polym 15:1700160 DOI

Kümmerer K, Al-Ahmad A, Mersch-Sundermann V (2000) Biodegradability of some antibiotics, elimination of the genotoxicity and affection of wastewater bacteria in a simple test. Chemosphere 40:701–710 DOI

Li Y, Niu J, Wenlong W (2011) Photolysis of Enrofloxacin in aqueous systems under simulated sunlight irradiation: kinetics, mechanism and toxicity of photolysis products. Chemosphere 85:892–897 DOI

Rizzo L, Fiorentino A, Anselmo A (2013) Advanced treatment of urban wastewater by UV radiation: effect on antibiotics and antibiotic-resistantE. coli strains. Chemosphere 92:171–176 DOI

Roth N, Käsebohrer A, Mayrhofer S, Zitz U, Hofacre C, Domig K (2019) The application of antibiotics in broiler production and the resulting antibiotic resistance in Escherichia coli: a global overview. Poult Sci 98:1791–1804 DOI

Sanhueza L, Melo R, Montero R, Maisey K, Mendoza L, Wilkens M (2017) Synergistic interactions between phenolic compounds identified in grape pomace extract with natibioticx of different classes against Staphylococcus aureus and Escherichia coli. PLoS One 12(2):e0172273 DOI

Sturini M, Speltini A, Maraschi F, Pretali L, Profumo A, Fasani E, Albini A, Migigliavacca R, Nucleo E (2012) Photodegradation of fluoroquinolones in surface water and antimicrobial activity of the photopruducts. Water Res 46:5575–5582 DOI

Sturini M, Speltini A, Maraschi F, Pretali L, Ferri EN, Profumo A (2015)Sunlight-induced degradation of fluoroquinolones in wastewater effluent: photoproducts identification and toxicity. Chemosphere 134:313–318 DOI

Sukul P, Spiteller M (2007) Fluoroquinolones antibiotics in the environment. Rev Environ Contam Toxicol 191:131–154

Van Doorslaer X, Dewulf J, Van Langenhove H, Demeestere K (2014) Fluoroquinolone antibiotics: an emerging class of environmental micropollutants. Sci Total Environ 500-501C:250–269 DOI

Vasconcelos TG, Henriques DM, König A, Martins AF, Kümerer K (2009)Photo-degradation of the antimicrobial ciprofloxacin at high pH: identification and biodegradability assessment of the primary by-products. Chemosphere 76:487–493 DOI

Wammer KH, Korte AR, Lundeen RA, Sundberg JE, McNeill K, Arnold WA (2013) Direct photochemistry of three fluoroquinolone antibacterials: norfloxacin, ofloxacin and enrofloxacin. Water Res 47:439–448 DOI

Yamada M, Yoshida J, Hatou S, Yoshida T, Minegawa Y (2008) Mutations in the quinolone resistence determining region in Staphylococcus epidermidis recovered from conjunctiva and their assiciation with susceptibility to various fluoroquinolones. Br J Ophthalmol 92:848–851 DOI

Zhang Z, Xie X, Yu Z, Cheng H (2019) Influence of chemical speciation on phtochemical transformation of three fluoroquinolones (FQs) in water: kinetics, mechanism, and toxicity of photolysis products. Water Res 148:19–29 DOI

Selected widely prescribed pharmaceuticals: toxicity of the drugs and the products of their photochemical degradation to aquatic organisms