The interaction between Pseudomonas aeruginosa and the corneal epithelium. An electron microscopic study
G. A. Stern, A. Lubniewski and C. Allen
The interaction between Pseudomonas aeruginosa and the rabbit corneal
epithelium during the first hour after inoculation was studied using
scanning and transmission electron microscopy. Fifteen minutes after
inoculation, adherent bacteria were found on damaged or exposed basal
epithelial cells at the edge of an epithelial defect, and this adherence
was the result of an interaction between the bacterial and epithelial cell
membranes. Thirty minutes after inoculation, the adherent bacteria began to
penetrate the epithelial cells by the formation of "pockets" surrounding
the organisms, and after an additional 15 minutes the bacteria further
penetrated the cells as the pockets began to fill in with cellular
material. One hour after inoculation, only rare bacteria were seen on the
cell surfaces or within the margins of the epithelial defect. Transmission
electron microscopy, however, revealed many intracellular bacteria or
bacteria that had migrated between the basal epithelium and corneal stroma.
Therefore, it appears that the initiating events in Pseudomonas corneal
ulceration involve adherence to the damaged or exposed basal epithelial
cells by an interaction between the bacterial and cellular membranes, after
which the organisms are engulfed by the epithelial cell and reach the
corneal stroma by a process of transcellular migration.
