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Published on: May 12, 2020
Topical Vancomycin is More Efficient than Povidone-Iodine Treatment in Controlling Bacterial Growth in
Yunus Alkan1,2, Abdulgani Kaymaz1, Mustafa Behcet3
1Department of Ophthalmology, Bolu Abant Izzet Baysal University, Training and Research Hospital, Bolu, Turkey.
Abstract:
To evaluate the efficacy of topical vancomycin and povidone iodine (PI) application on methicillin-resistant Staphylococcus aureus (MRSA) keratitis model in rabbits.
Abstract:
MRSA keratitis was induced by injecting 0.1 mL MRSA containing 1000 colony-forming units (CFU) into central cornea of right eyes of 24 New Zealand White rabbits. Animals were divided into four groups (n = 6): control (treated with balanced salt solution), 50 mg/mL topical vancomycin, 5% topical PI, and combination; examined before and after treatment, and corneal tissues were harvested for analysis at 9th hour of treatment.
Abstract:
Bacterial load was determined as: 7.63 ± 0.82 log10 CFU/g in control group, 6.95 ± 1.66 log10 CFU/g in PI group, 4.67 ± 0.77 log10 CFU/g in combination group, and 4.33 ± 0.71 log10 CFU/g in vancomycin group (p = 0.001). Median of total clinical score increased significantly from 7 [range: 5-8] to 11.5 [range: 11-15] (p = 0.001) in control group, did not change (6 [range: 5-8] to 7 [range: 5-7]; p = 0.695) in vancomycin group, increased significantly from 7 [range: 5-8] to 12.5 [range: 10-14] (p < 0.001) in PI group, increased significantly from 6.5 [range: 5-7] to 8 [range: 7-9] in combination group (p = 0.002). Post-treatment clinical scores for chemosis, conjunctival injection, iritis, hypopyon, epithelial erosion, and corneal infiltrate were significantly lower in vancomycin-treated groups compared to others (p < 0.05). In PI-treated groups, especially scores for chemosis, conjunctival injection, epithelial erosion and corneal infiltrate were significantly higher than vancomycin (p < 0.05).
Abstract:
Topical vancomycin significantly inhibited bacterial growth in MRSA keratitis. However, PI was ineffective in controlling this growth; additionally, exerted toxic effect on ocular surface. When vancomycin was combined with PI, no additional increase in efficacy of treatment was detected compared to only vancomycin.
Insights
Topical vancomycin effectively treats methicillin-resistant Staphylococcus aureus (MRSA) keratitis in rabbits by inhibiting bacterial growth. Povidone iodine (PI) was ineffective and caused ocular toxicity, with no added benefit when combined with vancomycin.
Area of Science:
- Ophthalmology
- Microbiology
- Pharmacology
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of bacterial keratitis.
- Effective treatment options for MRSA keratitis are crucial to prevent vision loss.
Purpose of the Study:
- To evaluate the efficacy of topical vancomycin and povidone iodine (PI) in a rabbit model of MRSA keratitis.
- To compare the effects of vancomycin, PI, and their combination on bacterial load and clinical signs of keratitis.
Main Methods:
- MRSA keratitis was induced in New Zealand White rabbits.
- Animals were treated with balanced salt solution (control), topical vancomycin, topical PI, or a combination.
- Bacterial load and clinical scores (chemosis, conjunctival injection, iritis, hypopyon, epithelial erosion, corneal infiltrate) were assessed.
Main Results:
- Topical vancomycin significantly reduced bacterial load and improved clinical scores compared to control and PI groups.
- Povidone iodine (PI) was ineffective in reducing bacterial load and showed signs of ocular toxicity.
- The combination of vancomycin and PI did not offer additional therapeutic benefit over vancomycin alone.
Conclusions:
- Topical vancomycin is an effective treatment for MRSA keratitis in rabbits.
- Povidone iodine (PI) is not effective and may be detrimental to the ocular surface in MRSA keratitis.
- Combination therapy with vancomycin and PI does not enhance treatment efficacy.
