Purpose: To investigate the antimicrobial efficacy of a novel
amphibian antimicrobial peptide, Esculentin1-21 (Esc1-21), in vitro
and in a murine model of Pseudomonas aeruginosa (PA) keratitis.
Methods: Standard cfu assays were used to determine the MIC of
Esc1-21 against PA strains ATCC 27853 and 19660. The effects of
physiological salt concentrations and tears (basal and reflex) on antipseudomonal
activity were also tested. MTT assays were performed
to determine if Esc1-21 was toxic to a human corneal epithelial cell
line (HCEC). For in vivo studies corneas of C57BL/6 mice were
scratched; then 105-106 cfu PA ATCC19660 applied topically. Esc1-21
(40 μM) or PBS was applied topically three times/day for up to 5
days (pi) post-infection. At 1, 3 and 5 days pi, severity of infection was graded by slit-lamp, neutrophil infiltration was assessed by MPO
assay and viable bacterial counts were determined.
Results: The MIC for Esc1-21 was 4 μM and 32 μM for ATCC
27853 and 19660 (n=3) respectiv
