Levofloxacin more effective than vancomycin

Levofloxacin is a viable treatment for endophthalmitis, according to a study published online ahead of print by the British Journal of Ophthalmology.

Consuelo Ferrer, PhD of the Vissim Institute of Ophthalmology, Alicante, Spain and colleagues compared intravitreal 1.5% levofloxacin monotherapy with 1% vancomycin plus 2.2% ceftazidime combination therapy against bacterial endophthalmitis in 75 New Zealand White rabbit eyes.

The eyes were injected with Staphylococcus epidermidis, Staphylococcus aureus or Pseudomonas aeruginosa and then treated with one of the two therapy options, or control. Vitreous and aqueous humour samples were harvested 24 hours after treatment, and colony-forming units (CFU) per millilitre of each sample was tested at day two, three, five and eight.

No statistically significant difference in CFU/ml between the levofloxacin and the combination treatment was seen in the vitreous humour of any of the eyes. In aqueous humour of the S. epidermidis eyes, levofloxacin monotherapy produced a 3 log decrease in CFU/ml over control; combination therapy produced a 5 log decrease in CFU/ml over control. In aqueous humour of the S. aureus eyes, levofloxacin monotherapy produced a 4 log decrease in CFU/ml over control; combination therapy produced a 2 log decrease in CFU/ml over control. In aqueous humour of the P. aeruginosa eyes, levofloxacin monotherapy produced a 5 log decrease in CFU/ml over control; combination therapy produced a 3–4 log decrease in CFU/ml over control.

The researchers concluded that levofloxacin is effective in the treatment of endophthalmitis in an experimental model although it must be tested further before it can be used in a clinical setting.