Evaluation of antibacterial efficacy of photo-activated riboflavin using ultraviolet light (UVA).

Abstract

BACKGROUND:

To evaluate the antibacterial efficacy of photo-activated riboflavin using Ultraviolet A (UVA) on three bacterial strains commonly detected in keratitis.

METHODS:

Three bacterial strains (Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa) were cultured on blood/hematin-agar plates and dispersed in PBS. Dispersion was done of 10 microl of bacterial stock-solutions in 90 microl of RPMI, where different riboflavin molarities had been added, to achieve a bacterial concentration of 1-4 x 10 (4)/ml. Riboflavin end molarities before illumination were 0, 100, 200, 300 and 400 microM. Each solution had a negative control. The solutions were illuminated with UVA (365 nm) for 30 minutes (5.4 J/cm(2)) and then continued for a total time of 60 minutes (10.8 J/cm(2)). A count of CFU was conducted after incubation and results compared.

RESULTS:

In all tested strains, a slight decrease of bacteria was seen when exposed to UV for 30 minutes. A doubling of the UV dose showed a marked decrease of bacterial count in all bacteria tested. The combination of UV and riboflavin showed a more extensive reduction of CFU, confirming an interaction effect between UV and riboflavin.

CONCLUSION:

Riboflavin photo-activation using UVA (365 nm) can achieve an extensive eradication of bacteria, and the combination is more potent in reducing bacterial number than UV alone.

• Authors: Karim Makdoumi, Anders Bäckman, Jes Mortensen, Sven Crafoord
• Journal: Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie (Graefes Arch Clin Exp Ophthalmol) Vol. 248 Issue 2 Pg. 207-12 (Feb 2010) ISSN: 1435-702X [Electronic] Germany
• PMID: 19921518 (Publication Type: Journal Article)

Chemical References

• Anti-Bacterial Agents
• Photosensitizing Agents
• Riboflavin

Topics

• Anti-Bacterial Agents (pharmacology)
• Colony Count, Microbial
• Humans
• Keratitis (drug therapy, microbiology)
• Photosensitizing Agents (pharmacology)
• Pseudomonas Infections (drug therapy, microbiology)
• Pseudomonas aeruginosa (drug effects, radiation effects)
• Riboflavin (pharmacology)
• Staphylococcal Infections (drug therapy, microbiology)
• Staphylococcus aureus (drug effects, radiation effects)
• Staphylococcus epidermidis (drug effects, radiation effects)
• Ultraviolet Rays