AIM: To evaluate the efficacy of 1.5% intravitreal levofloxacin versus combined therapy vancomycin and ceftazidime in an experimental model of bacterial endophthalmitis.
METHODS: The right eye of 75 New Zealand rabbits was inoculated in the vitreous cavity with strains of Staphylococcus epidermidis, Staphylococcus aureus or Pseudomonas aeruginosa. The study evaluated 1.5% levofloxacin treatment against 1% vancomycin plus 2.2% ceftazidime, and a control group. 24 hours after treatment, 100 µl of vitreous and aqueous were harvested, and the number of CFU per ml was determined. The microbiological status of vitreous and aqueous humor samples was tested at day 2, 3, 5 and 8. The Peyman classification was used to assess the severity of endophthalmitis.
RESULTS: For the S. epidermidis endophthalmitis model, levofloxacin treatment produced approximately a 3-log decrease in CFU per ml of vitreous relative to that in untreated eyes (p = 0.023), while vancomycin plus ceftazidime produced 5-log reductions in CFU/ml (p=0.023). However, S. aureus model levofloxacin treatment produced approximately 4-log reduction in CFU /ml, while vancomycin plus ceftazidime produced approximately 2-log reductions in CFU/ml relative to that of the control (p=0.018 and p=0.019 respectively). Treatment of rabbit eyes infected with P. aeruginosa with levofloxacin produced 5-log reduction in CFU /ml of vitreous, while vancomycin plus ceftazidime produced approximately 3-4 log reductions in CFU/ml relative to that of the control (p = 0.001). However, there was no significant difference found between levofloxacin and vancomycin plus ceftazidime on comparing the reduction of CFU per ml of vitreous for any of the bacterial strains studied.
CONCLUSIONS: Levofloxacin appears to be effective in treating experimental endophthalmitis in the rabbit model. Further studies, especially on toxicity of intravitreal levofloxacin, are required before determining the clinical role of the drug for postoperative therapy.
- Eye (Globe)
- Treatment Medical
- bacterial endophthalmitis
- experimental model