Debarun Dutta, BOptom, is pursuing a PhD under the supervision of Mark Willcox at the School of Optometry and Vision Science, University of New South Wales and the Brien Holden Vision Institute, in Australia. He was recently awarded an Ezell Fellowship from the American Academy of Optometry.
About the study
Authors: Debarun Dutta 1,2 and Mark Willcox 2
Purpose: Development of antimicrobial contact lens could have the capacity to reduce the rate of contact lens related adverse events. The purpose of this study was to evaluate two cationic peptides coated on contact lenses for their activity against P. aeruginosa and S. aureus.
Methods: Minimal inhibitory concentration (MIC) of two peptides, Melimine (a synthetic peptide) and Cathelicidin (LL37) was measured against strains of P. aeruginosa and S. aureus. Increasing concentrations of peptides were covalently bound to contact lenses. Antimicrobial activity against the bacteria was evaluated by measuring the amount of cell death compared to control lenses with no melimine or LL37.
Results: MIC of LL37 against both P. aeruginosa and S. aureus was 3.9µg ml-1, whereas for Melimine against the same bacteria it was 500 µg ml-1 and 250 μg ml-1 respectively. Contact lenses covalently reacted with 1mg ml-1 Melimine showed 0.8 log and 2.6 log inhibition against P. aeruginosa and S. aureus respectively whereas no inhibition was detected with LL37 at that concentration. Contact lenses prepared with 3mg ml-1 melimine and LL37 showed 3.1 log and 3.3 log inhibition against P. aeruginosa , 3.9 log and -0.2 log inhibition against S. aureus respectively.
Conclusions: Whilst Melimine on contact lenses had activity against both bacterial types; covalently bound LL37 was not active against S. aureus. These differences suggest different mechanisms of action against Gram-negative or Gram-positive bacteria by these two cationic peptides.
- Brien Holden Vision Institute, Sydney, NSW, Australia
- School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia