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Antimicrobial peptides: a potential role in ocular therapy
1Cooperative Research Centre For Eye Research and Technology, The University of New South Wales, Sydney, Australia. y.aliwarga@cclru.unsw.edu.au
Abstract:
Bacterial pathogens are often involved in contact lens-related adverse responses. This study aimed to find antimicrobial peptides and proteins that effectively eradicate or inhibit ocular bacteria. The antimicrobials were screened against gram-negative and gram-positive bacteria originating from ocular sources. The viability of these ocular bacteria was measured after exposure to the peptides and proteins. Two conditions were used to grow bacteria, low nutrient phosphate-buffered saline and high nutrient tryptone soya broth. Samples were taken at different times up to 48 h. In low nutrient conditions, protamine was found to be the most effective against all strains. Melittin was very effectve against all strains except Serratia and one Pseudomonas isolate which were partially affected. In high nutrient condition, only melittin was effective in killing Staphylococcus aureus. Protamine and the combination of protamine and melittin had the greatest effect in eradicating the bacteria tested in low nutrient condition. Protamine alone and its combination with melittin may have potential therapeutic agents for ocular infections in an era of emerging antibiotic resistance.
Insights
Antimicrobial peptides like protamine show promise for treating eye infections. They effectively kill ocular bacteria, offering a potential solution against rising antibiotic resistance.
Area of Science:
- Ophthalmology
- Microbiology
- Biochemistry
Background:
- Bacterial pathogens are a significant cause of adverse reactions associated with contact lens wear.
- The rise of antibiotic resistance necessitates the exploration of alternative antimicrobial agents.
Purpose of the Study:
- To identify antimicrobial peptides and proteins capable of eradicating or inhibiting common ocular bacteria.
- To evaluate the efficacy of selected antimicrobials against Gram-negative and Gram-positive ocular bacteria under different nutrient conditions.
Main Methods:
- Screening of antimicrobial peptides and proteins against ocular bacterial isolates.
- Assessment of bacterial viability after exposure to antimicrobials in low (phosphate-buffered saline) and high (tryptone soya broth) nutrient environments.
- Time-course analysis of bacterial response up to 48 hours.
Main Results:
- Protamine demonstrated broad-spectrum efficacy against all tested bacterial strains in low-nutrient conditions.
- Melittin was effective against most strains, with partial activity against Serratia and a Pseudomonas isolate.
- In high-nutrient conditions, melittin was effective against Staphylococcus aureus; protamine and its combination with melittin showed significant eradication in low-nutrient settings.
Conclusions:
- Protamine and melittin, particularly in combination, show potential as therapeutic agents for ocular infections.
- These antimicrobial peptides offer a promising alternative in the face of increasing antibiotic resistance in ocular pathogens.