EFFECT OF HYBRID PEPTIDES OF CECROPIN-A AND MELITTIN IN AN EXPERIMENTAL-MODEL OF BACTERIAL KERATITIS

Synthetic peptides, ranging from 12 to 18 residues, containing partial sequences from natural cecropin A and melittin were tested for activi ty in an experimental pseudomonas keratitis model in rabbits. In separ ate experiments, two Pseudomonas aeruginosa strains: (a) a clinical is olated strain, and (b) an American Type Culture Collection (ATCC) stra in, were inoculated into the stroma of one cornea of each rabbit. Pept ides were topically applied at 0.1% in phosphate-buffered saline (PBS) and compared with PBS alone and 0.3% gentamicin eye drops. Clinical e valuation, based on the McDonald-Shadduck scale, was performed during a >48-h period after the bacterial inoculation. The peptide-treated an imals showed significantly lower (p < 0.05) inflammatory signs and low er anterior-segment bacterial damage compared with PBS-treated animals , after the first 6 h. The antiinflammatory/antimicrobial activity was non significantly different (p > 0.05) from that in animals treated w ith gentamicin. We conclude that peptides keeping the sequence KWKLFKK from cecropin A and at least the sequence VLKVL from melittin show pr omise as novel agents in topical ocular therapy of bacterial keratitis .