EXPERIMENTAL STUDIES WITH STAPHYLOCOCCUS-AUREUS IN M-K MEDIA

Abstract

The survival of a pathogenic bacterium in McCarey-Kaufman [M-K] modified tissue culture medium 199 was studied. Rabbit eyes were inoculated with a S. aureus suspension. Upon enucleation 12 h later no clinical signs of infection were noted. Limbal-conjunctival cultures were obtained on all eyes before and after application of antibiotic [a neomycin sulfate-polymyxin B sulfate combination]. Corneas were stored in M-K media with standard penicillin-streptomycin added and cultured up to 48 h. Some infecting organisms were isolated from M-K media containing scleral-corneal buttons of eyes which had been treated topically with antibiotic after removal from the rabbits, but none were isolated from M-K media containing scleral-corneal buttons of eyes which had been completely immersed in antibiotic following removal. Direct cultures from corneal buttons taken 48-72 h after antibiotic application by either method showed 1-3 colonies/plate in 25% of eyes. Improperly applied antibiotic allowed some survival of S. aureus in the media. These results have relevance to ensuring sterility in donor corneas stored in M-K medium prior to grafting.