Parenteral therapy with trisulfapyramidines (Triple Sulfas) for 21 days did not alter the bacterial flora of the conjunctiva and lid margin. Topical therapy with tetracycline and erythromycin for six weeks significantly reduced the isolation frequency of Staphylococcus albus, increased the number of S albus strains resistant to either drug, and increased the number of sterile cultures. It is apparent that prolonged administration of topically applied tetracycline and erythromycin can reduce the incidence of certain bacteria on conjunctiva and lid margin, but such treatment may promote growth of resistant, wild-type allele strains which populate the ecological niche created by the therapy. There was no tendency for gram-negative overgrowth to occur following treatment with the three drugs in this study.
Olson CL. Bacterial Flora of the Conjunctiva and Lid MarginEffects of Parenteral Trisulfapyramidines and Topical Tetracycline and Erythromycin. Arch Ophthalmol. 1969;82(2):197-202. doi:10.1001/archopht.1969.00990020199009