Infectious crystalline keratopathy. The role of bacterial exopolysaccharide.
OBJECTIVE
Infectious crystalline keratopathy is a unique pauci-inflammatory infection of the cornea most commonly due to viridans type streptococci. We investigated the hypothesis that production of exopolysaccharide by streptococci, a property that can be induced by growth conditions, may contribute to the pathogenesis of infectious crystalline keratopathy by suppressing the ocular immune response.


METHODS
Streptococcus sanguis type II was grown under two conditions, conventionally in brain-heart infusion broth and in 5% sucrose-supplemented brain-heart infusion broth, to promote exopolysaccharide formation. Rabbit corneas were inoculated by passage of 9-0 silk sutures soaked in bacterial suspensions.


RESULTS
Arborizing, sharply demarcated pauci-inflammatory lesions were noted in 71% of rabbit corneas inoculated with S sanguis type II grown in sucrose-supplemented media and in 25% of control corneas (P = .05). Suppurative lesions developed in the remaining corneas. Histologic evaluation of infectious crystalline keratopathy lesions revealed characteristic features.


CONCLUSIONS
Increased exopolysaccharide formation by S sanguis type II is associated with production of infectious corneal lesions that resemble those of infectious crystalline keratopathy.
Hunts
J H
JH
Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030.
Matoba
A Y
AY
Osato
M S
MS
Font
R L
RL
D000818:Animals; D003315:Cornea / Q000378:metabolism / Q000382:microbiology; D015818:Eye Infections, Bacterial / Q000378:metabolism / Q000382:microbiology*; D007634:Keratitis / Q000378:metabolism / Q000382:microbiology*; D008828:Microbiological Techniques; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis / Q000502:physiology*; D011817:Rabbits; D013290:Streptococcal Infections / Q000378:metabolism / Q000382:microbiology*; D013298:Streptococcus sanguis / Q000378:metabolism*
D011135:Polysaccharides, Bacterial