Role of coagulase-negative staphylococci and micrococci in ocular disease.

Forty-nine strains of coagulase-negative staphylococci and 26 strains of micrococci isolated from human eyes were classified by the Baird-Parker system of 1966. The staphylococci belonged to subgroups II, III, IV, and V with one strain each in subgroups III and IV. However, when biotyped by Baird-Parker's system of 1974, less than 50% (23/49) of strains were typable and they belonged to biotypes 1 and 2. With our proposed modified classification all strains could be classified into biotypes 1, 2, and 3. All the 26 strains of micrococci belonged to subgroup VII. Staphylococci isolated from diverse sources produced, qualitatively and quantitatively, different corneal pathology in rabbits when compared to those isolated from healthy conjunctiva. This bore no relation to the present system of subtyping based on biochemical reactions. Micrococci were incapable of producing experimental corneal lesions in the rabbit.