Bacterial aspects of chronic blepharitis.

Patients with all forms of chronic blepharitis were thoroughly evaluated. These patients were found to have evidence for a primary bacterial component in the disease process only in the clinical staphylococcal and mixed seborrheic/staphylococcal forms of chronic blepharitis. Evidence was found for a shared common pathway for Staphylococcus aureus, coagulase negative staphylococci, and Propionibacterium acnes to contribute to the disease process. These organisms were found to produce lypolytic exoenzymes including fatty wax esterase, cholesteryl esterase, and triglyceride lipase. Statistically significantly larger numbers of coagulase negative staphylococci were found to produce these enzymes in patients with the various forms of seborrheic blepharitis and meibomian keratoconjunctivitis. Additionally, abnormalities in the free fatty acid component of the meibomian secretions were found in these patients supporting the hypothesis that lypolytic exoenzymes produced by bacteria might alter the meibomian secretion. Even though a primary pathogen is identifiable only in staphylococcal and mixed seborrheic/staphylococcal blepharitis, several different bacteria may contribute to the expression of disease in all other forms of chronic blepharitis.