Related Experiment Videos
[Adherence of Pseudomonas aeruginosa to the rabbit corneal epithelium]
1Dept. of Ophthalmol., Niigata Univ. School of Med., Japan.
Abstract:
Adherence of bacteria to the corneal epithelium is the first step in the pathogenesis of corneal infection. Keratitis caused by Pseudomonas aeruginosa usually occurs among the contact lens wearers. Adherence of Pseudomonas aeruginosa to rabbit corneal epithelium, damaged by one week of hard contact lens wear, was examined histologically. The cornea was excised for scanning electron microscopy at 5, 15, 30 and 60 minutes after inoculation of Pseudomonas aeruginosa (0.2 ml, 10(8)CFU/ml). Pseudomonas aeruginosa did not adhere to the intact corneal epithelium, but traumatized cornea provided a site for adherence. In rabbits in which the eyelid was opened by lid retractors, large numbers of organisms were observed adhering to the injured cornea mediated by ocular surface mucin. Thirty minutes after inoculation, the adherent bacteria began to penetrate the epithelial cells and surface mucin by the formation of pockets surrounding the organism.
Insights
Pseudomonas aeruginosa bacteria do not adhere to healthy corneas. However, damaged corneal epithelium from contact lens wear allows bacterial adherence and invasion, initiating infection.
Area of Science:
- Ophthalmology
- Microbiology
- Pathogenesis
Background:
- Bacterial adherence to the corneal epithelium initiates corneal infection.
- Pseudomonas aeruginosa is a common cause of keratitis, particularly in contact lens wearers.
Purpose of the Study:
- To investigate the adherence of Pseudomonas aeruginosa to damaged rabbit corneal epithelium.
- To examine the early stages of bacterial invasion following adherence.
Main Methods:
- Rabbit corneas were damaged by one week of hard contact lens wear.
- Scanning electron microscopy was used to examine bacterial adherence at 5, 15, 30, and 60 minutes post-inoculation.
- Pseudomonas aeruginosa (0.2 ml, 10(8) CFU/ml) was inoculated onto the corneal surface.
Main Results:
- Pseudomonas aeruginosa did not adhere to intact corneal epithelium.
- Traumatized corneal epithelium, mediated by ocular surface mucin, facilitated significant bacterial adherence.
- Bacterial penetration into epithelial cells and mucin began around 30 minutes post-inoculation.
Conclusions:
- Contact lens-induced corneal trauma creates a niche for Pseudomonas aeruginosa adherence.
- Ocular surface mucin plays a role in mediating bacterial attachment to the injured cornea.
- Early bacterial invasion of the corneal epithelium occurs rapidly after adherence.