title: Diffusion of ofloxacin in the endocarditis vegetation assessed with synchrotron radiation UV fluorescence microspectroscopy.
abstract: The diffusion of antibiotics in endocarditis vegetation bacterial masses has not been described, although it may influence the efficacy of antibiotic therapy in endocarditis. The objective of this work was to assess the diffusion of ofloxacin in experimental endocarditis vegetation bacterial masses using synchrotron-radiation UV fluorescence microspectroscopy. Streptococcal endocarditis was induced in 5 rabbits. Three animals received an unique i.v. injection of 150 mg/kg ofloxacin, and 2 control rabbits were left untreated. Two fluorescence microscopes were coupled to a synchrotron beam for excitation at 275 nm. A spectral microscope collected fluorescence spectra between 285 and 550 nm. A second, full field microscope was used with bandpass filters at 510-560 nm. Spectra of ofloxacin-treated vegetations presented higher fluorescence between 390 and 540 nm than control. Full field imaging showed that ofloxacin increased fluorescence between 510 and 560 nm. Ofloxacin diffused into vegetation bacterial masses, although it accumulated in their immediate neighborhood. Fluorescence images additionally suggested an ofloxacin concentration gradient between the vegetation peripheral and central areas. In conclusion, ofloxacin diffuses into vegetation bacterial masses, but it accumulates in their immediate neighborhood. Synchrotron radiation UV fluorescence microscopy is a new tool for assessment of antibiotic diffusion in the endocarditis vegetation bacterial masses.
authors.affiliation: Université de Nantes, EA3826 Thérapeutiques cliniques et expérimentales des infections, Nantes, France. eric.batard@chu-nantes.fr
authors.forename: Eric
authors.initials: E
authors.lastname: Batard
authors.forename: Fréderic
authors.initials: F
authors.lastname: Jamme
authors.forename: Sandrine
authors.initials: S
authors.lastname: Villette
authors.forename: Cédric
authors.initials: C
authors.lastname: Jacqueline
authors.forename: Marie-France
authors.initials: MF
authors.lastname: de la Cochetière
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Caillon
authors.forename: Matthieu
authors.initials: M
authors.lastname: Réfrégiers
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004058:Diffusion; D004697:Endocarditis, Bacterial / Q000188:drug therapy*; D006351:Heart Valves / Q000382:microbiology; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000379:methods*; D015242:Ofloxacin / Q000494:pharmacology*; D025341:Principal Component Analysis; D011817:Rabbits; D013298:Streptococcus sanguis / Q000378:metabolism; D017356:Synchrotrons; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; D015242:Ofloxacin