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Adherence of Pseudomonas aeruginosa to the mouse cornea. Epithelial v stromal adherence
Abstract:
Adherence of Pseudomonas aeruginosa to the cornea is the first step in the pathogenesis of Pseudomonas corneal ulceration. To determine the roles of epithelial and stromal adherence, a quantitative in vivo model of adherence was developed in the mouse. More than twice as many organisms were recovered from mouse corneas in which two linear abrasions were created compared with corneas totally denuded of epithelium. Scanning electron microscopy demonstrated poor adherence of Pseudomonas to bare stroma, but large numbers of organisms were seen adhering to the injured edge of epithelium. This study supports the concept that corneal trauma predisposes to Pseudomonas corneal ulceration by creating an injured epithelial edge as a site for adherence of the organisms, rather than by exposing areas of bare stroma susceptible to penetration by the organisms.
Insights
Pseudomonas aeruginosa corneal ulcers are caused by bacterial adherence to injured corneal epithelium, not exposed stroma. Trauma creates an epithelial edge, facilitating bacterial attachment and subsequent ulceration.
Area of Science:
- Ophthalmology
- Microbiology
- Pathogenesis
Background:
- Pseudomonas aeruginosa adherence to the cornea initiates corneal ulceration.
- Understanding adherence mechanisms is crucial for preventing and treating this condition.
Purpose of the Study:
- To investigate the distinct roles of corneal epithelial and stromal adherence in Pseudomonas aeruginosa pathogenesis.
- To quantify bacterial adherence in vivo following different types of corneal injury.
Main Methods:
- Development of a quantitative in vivo mouse model for studying bacterial adherence.
- Comparison of Pseudomonas aeruginosa recovery from corneas with linear abrasions versus those totally denuded of epithelium.
- Utilizing scanning electron microscopy to visualize bacterial adherence patterns.
Main Results:
- Significantly higher bacterial recovery from corneas with linear abrasions compared to completely denuded corneas.
- Demonstrated poor adherence of Pseudomonas aeruginosa to bare corneal stroma.
- Observed substantial bacterial adherence to the injured edge of the corneal epithelium.
Conclusions:
- Corneal trauma predisposes to Pseudomonas corneal ulceration by creating an injured epithelial edge.
- This injured epithelial edge serves as a primary site for bacterial adherence.
- Exposed stroma is less critical for initial Pseudomonas aeruginosa adherence and ulcer pathogenesis.