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Hydrogel contact lens-induced Pseudomonas keratitis in a rabbit model
J A Durán1, M F Refojo, K R Kenyon
1Eye Research Institute, Boston, MA 02114.
Abstract:
Unused soft contact lenses (SCL) containing 38.6% water (polymacon) and 70% water (lidofilcon A) were exposed to Pseudomonas aeruginosa (10(8) CFU/ml) for 60 min and washed. The contaminated lenses were used on rabbit eyes under the following conditions: for 1 h on a scratched corneal epithelium (16 eyes, four infected), for 24 h on normal cornea (eight eyes, none infected), and for 7 days on normal cornea (eight eyes, three bacterial infections and two noninfected epithelial defects). A control group of rabbits used an uncontaminated lens for 7 days (eight eyes, four noninfected epithelial defects). The control group and groups that wore contaminated lenses for 24 h and 7 days underwent tarsorrhaphy to keep the contact lens in place. In addition, three drops of the bacterial suspension were instilled in eyes with normal corneal epithelium (eight eyes, none infected) and scratched corneal epithelium (16 eyes, 13 infected). Results suggest that Pseudomonas-contaminated SCL give rise to keratitis only on an injured corneal epithelium and that a bacterial suspension is more pathogenic to the rabbit cornea than is a similar amount of bacteria on an SCL.
Insights
Pseudomonas-contaminated soft contact lenses (SCL) cause keratitis only in rabbits with injured corneas. A direct bacterial suspension proved more pathogenic than contaminated SCL.
Area of Science:
- Ophthalmology
- Microbiology
- Biomaterials Science
Background:
- Soft contact lenses (SCL) are widely used for vision correction.
- Bacterial contamination of SCL can lead to serious eye infections, such as keratitis.
- Pseudomonas aeruginosa is a common pathogen associated with contact lens-related microbial keratitis.
Purpose of the Study:
- To investigate the pathogenic potential of Pseudomonas aeruginosa-contaminated SCL on rabbit corneas.
- To compare the pathogenicity of contaminated SCL with direct bacterial suspension instillation.
- To determine the role of corneal integrity in SCL-related infections.
Main Methods:
- Unused SCL (polymacon and lidofilcon A) were contaminated with Pseudomonas aeruginosa.
- Contaminated SCL were applied to rabbit eyes with normal or scratched corneal epithelium for varying durations.
- A control group used uncontaminated SCL.
- Direct bacterial suspension was instilled into rabbit eyes.
- Tarsorrhaphy was used to secure lenses in some groups.
Main Results:
- Pseudomonas-contaminated SCL induced keratitis exclusively in eyes with pre-existing corneal epithelial defects.
- Direct instillation of Pseudomonas aeruginosa suspension was more pathogenic than contaminated SCL.
- No significant infections were observed in eyes with intact corneal epithelium wearing contaminated SCL.
- Control groups and those with intact corneas showed minimal to no infection.
Conclusions:
- Corneal epithelial integrity is a critical factor in the development of keratitis from contaminated SCL.
- Direct bacterial inoculation poses a higher risk of severe keratitis compared to SCL-associated contamination.
- These findings highlight the importance of proper contact lens hygiene and prompt management of corneal abrasions.