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Improved Enzyme Protection Assay to Study Staphylococcus aureus Internalization and Intracellular Efficacy of Antimicrobial Compounds
Published on: September 8, 2021
Experimental studies with Staphylococcus aureus in M-K media
Abstract:
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.
Insights
This study investigated Staphylococcus aureus survival in tissue culture media after antibiotic treatment. Improper antibiotic application allowed some bacterial survival, highlighting the importance of correct administration in preventing ocular infections.
Area of Science:
- Ophthalmology
- Microbiology
- Infectious Diseases
Background:
- Bacterial keratitis is a significant cause of vision loss.
- Effective antibiotic treatment is crucial for managing ocular infections.
- Understanding bacterial survival in culture media informs treatment strategies.
Purpose of the Study:
- To evaluate the survival of Staphylococcus aureus in McCarey-Kaufman (M-K) media.
- To assess the efficacy of antibiotic treatment on bacterial survival in rabbit eyes.
- To determine the impact of antibiotic application methods on bacterial recovery.
Main Methods:
- Inoculation of rabbit eyes with Staphylococcus aureus.
- Application of topical antibiotics and complete eye immersion.
- Culturing of corneal buttons and limbal-conjunctival samples.
- Storage of corneas in M-K media with antibiotics for up to 48 hours.
Main Results:
- No clinical signs of infection were observed 12 hours post-inoculation.
- Some Staphylococcus aureus recovery from media with topical antibiotics.
- No bacterial recovery from eyes after complete antibiotic immersion.
- 25% of corneal buttons showed 1-3 colonies after 48-72 hours, indicating partial survival.
Conclusions:
- Improperly applied antibiotics can lead to Staphylococcus aureus survival in ocular tissues.
- Complete antibiotic immersion appears more effective than topical application in eradicating bacteria.
- Further research is needed to optimize antibiotic delivery for ocular infections.
