Χημειοπροφύλαξη με μοξιφλοξασίνη σε πειραματική ενδοκαρδίτιδα αορτικής βαλβίδας από streptococcus oralis

Abstract

Objectives: Studies related to the prophylactic efficacy of newer fluoroquinolones against infective endocarditis are scarce. The aim of this study was to evaluate the efficacy of moxifloxacin, a quinolone active in vitro against Gram-positive cocci, in preventing streptococcal aortic valve endocarditis. Methods: Non-bacterial thrombotic endocarditis of the aortic valve was induced in rabbits by the insertion of a polyethylene catheter. Twenty-four hours later, rabbits were randomly assigned to a control group, and groups receiving either a single dose of moxifloxacin (15 mg/kg, intravenously), or two doses of ampicillin (40 mg/kg, intravenously), 2 h apart. Ampicillin and moxifloxacin were administered 0,5 and 1 h, respectively, prior to the intravenous inoculation of 107 CFU of Streptococcus oralis. The rabbits were sacrificed 3 days after bacterial challenge and vegetations were cultured quantitatively. Results: Seventeen out of 18 (94%) of the control animals developed infected vegetations. In rabbits challenged with this very high inoculum, moxifloxacin and ampicillin prevented endocarditis in 81% (p < 0.001 versus controls) and in 50% (p = 0,022 versus controls) of animals, respectively. The difference between ampicillin and moxifloxacin was not statistically significant (p = 0.128) (Fisher exact test). The mean ± SD bacterial densities in vegetations from rabbits infected (in log10CFU/g) were: Controls 9,28 ± 0,95a (n=17), ampicillin 7,78 ± 2,07b (n=7) and, moxifloxacin 8,38 ± 0,77c (n=3). Statitics: a vs b: p=0,065 (ns), a vs c: p=0,491 (ns) (Kruskal-Wallis test). Moxifloxacin levels at 1, 2, 4, 8 and 24 h post-dosing were (mean ± SD): 3,45±0,8 mg/L (n=13), 2,42±0,66 mg/L (n=14), 1,2±0,46 mg/L (n=13), 0,28±0,11 mg/L (n=13) and undetectable (n=6), respectively. Ampicillin levels at 0,5, 1, 2 h after the first dose and 2 h after the second dose were (mean ± SD): 9,56±3,72 mg/L, 3,24±1,19 mg/L, 0,58±0,48 mg/L, 0,73±0,47 mg/L, respectively (n=15). Conclusions: Moxifloxacin was at least as effective as ampicillin in preventing streptococcal endocarditis.