Corneal rings with gram-negative bacteria
B. J. Mondino, B. S. Rabin, E. Kessler, J. Gallo and S. I. Brown
Corneal rings have been described with corneal ulcerations caused by
Gram-negative bacteria. Corneal rings were produced by intracorneal
injections of viable Pseudomonas aeruginosa as well as heat-inactivated
suspensions of Gram-negative bacteria (P aeruginosa and Escherichia coli)
but not Gram-positive bacteria (Staphylococcus aureus) or Freund's
adjuvant. It is suggested that endotoxin is the factor responsible for
their production since purified endotoxin produced corneal rings after
intracorneal injection. Histopathological examination of the areas
corresponding to the corneal rings disclosed that the rings represented
accumulations of polymorphonuclear leukocytes. Direct immunofluorescent
studies of the corneal rings revealed staining for properdin and C3
complement but not for immunoglobulins. The present report suggests that
endotoxin has the ability to stimulate the alternate pathway of complement
through properdin activation with the production of chemotactic fragments
that attract polymorphonuclear leukocytes into the cornea.
