Biocidal Efficacy of Silver Impregnated Contact Lens Storage Cases In vitro.
Summary of "Biocidal Efficacy of Silver Impregnated Contact Lens Storage Cases In vitro."
PURPOSE:
Silver-impregnated contact lens (CL) storage cases aim to reduce microbial contamination of storage cases during use, however there are limited data on their effectiveness. This study evaluated early anti-microbial activity of silver-impregnated CL cases and silver release characteristics in-vitro.
METHODS:
Three silver-impregnated CL storage cases Microblock, i-clean(R) and Nano-case(R) were evaluated. The test organisms included the ISO14729 panel and 2 clinical isolates, Delftia acidovorans and Stenotrophomonas maltophilia. Each well of the case was challenged with 2mL of the organism in phosphate buffered saline at 10(3), 10(4), 10(5) and 10(6) CFU/mL. Survivors were recovered following 6, 10 and 24h incubation at 25 degrees C. Inductively-coupled plasma mass spectrometry was used to quantify the release of silver from the cases for similar incubation conditions and for time points up to 28 days.
RESULTS:
Significant differences in anti-microbial activity were observed between cases (p=0.001). Activity was only apparent after 24h. Microblock showed the highest activity against P. aeruginosa (2.4+/-0.5 log reduction at 10(6)), S. marcescens (3.3+/-0.9 log reduction), D. acidovorans (2.8+/-0.1 log reduction) and F. solani (0.5+/-0.2). i-clean(R) was most effective against S. aureus (5.4+/-1.1 log reduction), whereas Nano-case(R) showed the greatest activity against S. maltophilia (0.2+/-0.3 log reduction). Microblock was the only case to demonstrate the silver release over 28 days.
CONCLUSIONS:
Current silver-impregnated CL storage cases show variation in their in vitro antimicrobial activity. Broadly, the Microblock case demonstrated robust activity against most Gram-negative bacteria, while the i-clean(R) case was more effective against S. aureus. Silver release data suggest different modes of action for different cases.
Affiliation
University of New South Wales, Brien Holden Vision Institute, School of Optometry and Vision Science, Sydney, Australia.
Journal Details
This article was published in the following journal.
Name: Investigative ophthalmology & visual science
ISSN: 1552-5783
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20720221
- DOI: http://dx.doi.org/10.1167/iovs.09-4809
Medical and Biotech [MESH] Definitions
Catgut
Sterile collagen strands obtained from healthy mammals. They are used as absorbable surgical ligatures and are frequently impregnated with chromium or silver for increased strength. They tend to cause tissue reaction.
Silver Staining
The use of silver, usually silver nitrate, as a reagent for producing contrast or coloration in tissue specimens.
Contact Lens Solutions
Sterile solutions used to clean and disinfect contact lenses.
Lens Implantation, Intraocular
Insertion of an artificial lens to replace the natural CRYSTALLINE LENS after CATARACT EXTRACTION or to supplement the natural lens which is left in place.
Silver
Silver. An element with the atomic symbol Ag, atomic number 47, and atomic weight 107.87. It is a soft metal that is used medically in surgical instruments, dental prostheses, and alloys. Long-continued use of silver salts can lead to a form of poisoning known as ARGYRIA.
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