A New Treatment Experience in Pseudomonas Keratitis: Topical Meropenem and Cefepime

To compare the efficacy of topical meropenem and cefepime treatments with respect to moxifloxacin as new treatment options in an experimental Pseudomonas keratitis model.

Twenty-four rabbits in which keratitis are induced using Pseudomonas aeruginosa were divided into four groups according to treatment options. A solution of 50 mg/mL meropenem was prepared and topically applied to the first group, 50 mg/mL cefepime solution to the second group, topical 0.5% moxifloxacin drop to the third group, and topical isotonic (0.9% saline) solution to the fourth (control) group. The eyes were examined before and after treatment to score the clinical severity. After the subjects were sacrificed, their corneas were excised. To determine the efficacy of treatments, clinical score, bacterial load, and histopathological and immunohistochemical findings were evaluated.

When the three treatment groups were compared, there was a significant difference in the colony-forming unit (CFU) value, polymorph-nuclear leukocyte (PMNL) infiltration, and matrix metalloproteinase (MMP)-9 immunoreactivity (P=0.022, P=0.038, and P=0.037, respectively). The CFU values, PMNL infiltration scores and MMP-9 immunoreactivity were significantly lower in the meropenem and moxifloxacin groups compared with the cefepime group (P<0.05 for all). There was no significant difference between the meropenem and moxifloxacin groups in respect of the CFU values, PMNL infiltration, and MMP-9 immunoreactivity (P=0.842, P=0.784, and P=0.699, respectively).

The results of our study indicate that topical meropenem is at least as effective as topical moxifloxacin in the treatment of Pseudomonas keratitis. The meropenem and moxifloxacin are safer and suitable in the limited corneal invasion than cefepime. Thus, topical meropenem may be an alternative drug in the treatment of this condition. Clinical studies are needed to be conducted to assess this possibility more accurately.