Experimental studies with Staphylococcus aureus in M-K media.

This study reviewed the potential for survival of a pathogenic bacteria when inoculated into McCarey-Kaufman modified tissue culture media 199. A clinically isolated specimen of Staphylococcus aureus was selected and rabbit eyes inoculated with 0.1 ml. of the organism in a suspension of 1 to 3 x 10(-5). Upon enucleation 12 hours later no clinical signs of infection were noted. Limbal-conjunctival cultures were obtained on all eyes before and after application of the antibiotic. Corneas were stored in M-K media with standard penicillin-streptomycin added and cultured up to 48 hours. Our studies showed some recovery of the infecting organism from the media with topical antibiotic application but none following complete immersion of eyes in antibiotic. Direct cultures from corneal buttons taken 48 to 72 hours after antibiotic application by either method showed 1 to 3 colonies per plate in 25 per cent of eyes. In this study improperly applied antibiotic allowed some survival of S. aureus in the media.