Survey of conjunctival flora in dogs with clinical signs of external eye disease.

Bacteria were isolated 68% of the time from the conjunctival sacs of 120 dogs with conjunctivitis, blepharitis, dacryocystitis, or corneal ulcerations. Coagulase-positive Staphylococcus aureus was the most frequently isolated organism (68%); when both eyes were affected, S aureus was recovered from 29% of the dogs; and in dogs with 1 eye affected, S aureus was isolated from 23% of the affected eyes and in 18% of the nonaffected eyes. Other organisms recovered from eyes were coagulase-negative Staphylococcus epidermidis (27%), beta-hemolytic streptococcus (19%), alpha-hemolytic Streptococcus (17%), Escherichia coli (10%), Bacillus spp (11%), and Proteus spp (7%). It was concluded that S aureus may appear as a primary pathogen in ocular disease. When 1 eye is clinically affected, S aureus can be a potential invader of the normal eye.