Staphylococcal keratitis. Experimental model in guinea pigs
S. D. Davis, L. D. Sarff and R. A. Hyndiuk
An experimental model of staphylococcal keratitis in guinea pigs was
devised that is suitable for quantitative evaluation of therapy. The growth
curve in the cornea of a virulent strain of Staphylococcus aureus was
determined. The organism multiplied rapidly, reached a peak in about 12
hours, and began to decline in numbers after three days. Infections were
relatively resistant to therapy begun 24 hours after infection was
established. Treatment started earlier when fewer bacteria were present was
more effective than treatment begun later. Treatment begun at the time of
infection, which might be considered prophylaxis, was highly effective.
When treatment was begun eight hours after infection, tobramycin sulfate
and gentamicin sulfate solutions administered topically in doses of 20
mg/ml were more effective than topical bacitracin, erythromycin,
clindamycin phosphate, or a solution containing polymyxin B sulfate,
neomycin sulfate, and gramicidin. Bacitracin and erythromycin ointments
were ineffective.
