Pathologic mechanisms of multifocal choroiditis with retinal detachment after carotid injection of Streptococcus mutans and other bacteria in dogs.

Multifocal choroiditis with overlying retinal detachment occurs after carotid injection of certain bacteria in dogs. The ocular lesions occur mainly in the tapetal area of the retina, correlate with microabscesses in the inner choroid and subretinal space, and occasionally occur in the inner retina and anterior uveal tract. The major pathophysiologic factor involved in the dog model of septic choroiditis appears to be embolization of the choriocapillairies by "live" bacteria, which clump and adhere well to tissues. In the dosages used, antibiotics did not prevent or alter the severity of the fundus lesions.