Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
3358374 | International Journal of Antimicrobial Agents | 2016 | 6 Pages |
Abstract
In recent years, the emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains has been observed in ocular infections. Resistance of MRSA to second- and third-generation fluoroquinolones has increased interest in the fourth-generation fluoroquinolones. In this study, the antibacterial activity of gemifloxacin against MRSA ocular isolates in vitro and in a modified ex vivo rabbit keratitis model was investigated. In vitro susceptibility test results indicated that the minimum inhibitory concentrations (MICs) of gemifloxacin were lower than the MICs of other fluoroquinolones, including moxifloxacin (MIC50 range, 0.016-0.032âµg/mL; MIC90 range, 0.047-0.094âµg/mL). Results from the ex vivo keratitis model showed a statistically significant decrease in MRSA counts (0.5-2 log10 CFU/g; Pâ<0.05) in corneas treated with 0.3% gemifloxacin every 30âmin for 7âh. Moreover, the dose-response effect of different concentrations of gemifloxacin (3-3000âµg/mL) demonstrated that a dose of 30âµg/mL had the same efficacy as the highest dose of 3000âµg/mL against all S. aureus strains. Possibly, gemifloxacin reached a steady-state level in the cornea, as the fourth-generation fluoroquinolones have better anterior chamber penetration. This study demonstrated that 0.3% gemifloxacin ophthalmic solution may be an effective topical therapy for the treatment of MRSA keratitis. In addition, this reproducible, ethical and economic ex vivo infection model can be used as a mechanistically-based alternative to in vivo animal testing, bridging the gap between in vitro and in vivo results.
Keywords
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Applied Microbiology and Biotechnology
Authors
Andreana Marino, Anna Rita Blanco, Giovanna Ginestra, Antonia Nostro, Giuseppe Bisignano,