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Human corneal stromal tissue concentration after consecutive doses of topically applied 3.3% vancomycin
M Cahane1, G J Ben Simon, I S Barequet
1Goldschleger Eye Institute, Sheba Medical Center, Ramat Gan, 52621 Israel.
The British Journal of Ophthalmology
|December 25, 2003
Summary
Topical vancomycin eyedrops achieve high concentrations in corneal tissue, exceeding the minimum inhibitory concentration for common Gram-positive pathogens. This suggests efficacy for treating corneal infections before penetrating keratoplasty (PKP).
Area of Science:
- Ophthalmology
- Pharmacology
- Microbiology
Background:
- Bacterial keratitis is a significant cause of corneal opacity and vision loss.
- Topical antibiotics are crucial for managing corneal infections, particularly before surgical interventions like penetrating keratoplasty (PKP).
- Vancomycin is a key antibiotic for treating Gram-positive bacterial infections, including those affecting the cornea.
Purpose of the Study:
- To quantify vancomycin penetration into human corneal stromal tissue.
- To assess the efficacy of topical vancomycin eyedrops administered before PKP.
- To compare vancomycin concentrations in different corneal conditions.
Main Methods:
- A study involving 24 patients undergoing PKP (7 with keratoconus, 17 with corneal scar/decompensation).
- Patients received topical vancomycin eyedrops (33 mg/ml) at specific intervals before surgery.
- Corneal tissue vancomycin levels were determined using a bioassay.
Main Results:
- Mean vancomycin concentration in corneal stromal tissue was 46.7 µg/g.
- This concentration was 4 to 20 times higher than the MIC90 for Staphylococcus aureus.
- Higher vancomycin stromal concentration to protein ratio was observed in non-keratoconus patients.
Conclusions:
- Topical vancomycin effectively penetrates corneal tissue, reaching concentrations well above the MIC90 for major Gram-positive pathogens.
- These findings support the use of vancomycin eyedrops for pre-operative treatment in patients undergoing PKP.
- Corneal tissue characteristics may influence vancomycin penetration and retention.