Quantitative antibiotic sensitivity determinations of Staphylococcus aureus isolated from eye cultures

The sensitivities of 108 strains of Staphylococcus aureus, isolated from patients with a variety of ocular conditions, were tested quantitatively against nine antibiotics by means of a microtiter broth-dilution method. Of the nine antibiotics, cephalothin sodium had the lowest (and therefore the best) minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC). The MBC and MIC of gentamicin sulfate were very close to those of cephalothin. The MBCs and MICs of erythromycin, ampicillin sodium, penicillin, tetracycline, methicillin sodium, and carbenicillin disodium were moderately good. Chloramphenicol had the poorest response.

Marginal corneal ulcer due to beta-streptococcus

A 72-year-old woman with a low-grade nasolacrimal duct obstruction developed a hyperacute conjunctivitis caused by beta-hemolytic streptococci. This condition has been termed "conjunctivitis of Morax". An unusual feature consisting of a large, marginal furrow-like corneal ulcer was noted associated with a plastic iritis. The condition improved with the use of topical erythromycin, irrigation of the lacrimal sac with aqueous penicillin and oral penicillin. We believe that the marginal corneal ulcer was an actual infection of the corneal stroma resulting from the intense conjunctival chemosis trapping the exudate between the conjunctiva and the corneal epithelium, thus causing a breakdown of the corneal epithelium and allowing the organism to gain access to the stroma. Conjunctivitis of Morax can be clinically differentiated from a conjunctivitis associated with pneumococcal dacryocystitis and from the acute and hyperacute purulent conjunctivis due to infection with Neisseria.

Proteus species isolated from human eyes

Of 34 species of Proteus isolated from human eyes, 29 (85%) were P. mirabilis and five (15%) were P. morganii. In vitro antibiotic sensitivity studies showed that gentamicin best controlled both P. mirabilis and P. morganii of all the antibiotics tested. In vivo tests on experimental Proteus infections of rabbit coreas, treated with gentamicin and tobramycin, yielded comparable clinical results, but gentamicin was more effective in eliminating the organism from the experimental lesions.

Nebcin in the treatment of experimental Pseudomonas keratitis

When the ocular toxicity and the in vivo and in vitro effects of gentamicin, Nebcin, and saline solution were compared in experimentally induced Pseudomonas keratitis in rabbits, both antibiotics showed the same toxicity for the rabbits' conjunctival tissues. But Nebcin showed better in vitro and in vivo results than gentamicin, and the clinical effect was confirmed by culture study: significant numbers of organisms were recovered from the corneas of the gentamicin-treated rabbits but none from the corneas of the Nebcin-treated rabbits.