Related Experiment Videos
Topical antibiotic therapy of Pseudomonas aeruginosa keratitis
Abstract:
The in vivo antibacterial effectiveness in the rabbit cornea of several commercially available ophthalmic antibiotic preparations was determined against a single strain of Pseudomonas aeruginosa isolated from a human corneal ulcer. Each antibiotic was instilled topically at hourly intervals, and the number of residual viable organisms in the cornea subsequently was ascertained. In vivo measurements correlated well with in vitro data and with generally held clinical impressions. Three antibiotics, gentamicin sulfate, polymyxin B sulfate, and colistin sulfate, suppressed corneal growth of P aeruginosa in commercially available concentrations. Gentamicin was slightly more effective than polymyxin B; both drugs were substantially more effective than colistin. Formulations of gentamicin and polymyxin B containing approximately four times the quantity of drug found in commercial preparations eliminated this P aeruginosa strain from the cornea much more rapidly than did the commercial preparations.
Insights
This study evaluated ophthalmic antibiotics against Pseudomonas aeruginosa in rabbit corneas. Gentamicin and polymyxin B showed significant effectiveness, with higher concentrations clearing the infection faster.
Area of Science:
- Ophthalmology
- Microbiology
- Pharmacology
Background:
- Pseudomonas aeruginosa is a common cause of bacterial keratitis.
- Ophthalmic antibiotic efficacy can vary, necessitating in vivo evaluation.
- Rabbit cornea models are suitable for studying ocular infections.
Purpose of the Study:
- To determine the in vivo antibacterial effectiveness of commercial ophthalmic antibiotics against Pseudomonas aeruginosa.
- To compare the efficacy of gentamicin sulfate, polymyxin B sulfate, and colistin sulfate.
- To assess the impact of increased antibiotic concentrations on bacterial clearance.
Main Methods:
- Antibacterial effectiveness was tested in vivo using rabbit corneas.
- Ophthalmic antibiotic preparations were instilled topically at hourly intervals.
- Residual viable Pseudomonas aeruginosa organisms in the cornea were quantified.
Main Results:
- Gentamicin sulfate, polymyxin B sulfate, and colistin sulfate suppressed corneal Pseudomonas aeruginosa growth.
- Gentamicin was more effective than polymyxin B, which was more effective than colistin.
- Higher concentrations (four times commercial) of gentamicin and polymyxin B cleared the bacteria more rapidly.
Conclusions:
- Commercial ophthalmic antibiotics, particularly gentamicin and polymyxin B, are effective against Pseudomonas aeruginosa in vivo.
- Increased antibiotic concentrations enhance the rate of bacterial clearance from the cornea.
- In vivo findings align with in vitro data and clinical expectations for ophthalmic antibiotic treatment.