Kamil Bilgihan1, Ayse Kalkanci2, Huseyin Baran Ozdemir1, Reyhan Yazar2, Funda Karakurt2, Erdem Yuksel1, Feza Otag3, Nilgun Karabicak4, Sevtap Arikan-Akdagli5. 1. a Department of Opthalmology , School of Medicine, Gazi University , Ankara , Turkey. 2. b Department of Medical Microbiology , School of Medicine, Gazi University , Ankara , Turkey. 3. c Department of Medical Microbiology , School of Medicine, Mersin University , Mersin , Turkey. 4. d Mycology Reference Laboratory, Public Health Institution of Turkey , Ankara , Turkey. 5. e Department of Medical Microbiology , School of Medicine, Hacettepe University , Ankara , Turkey.
Abstract
PURPOSE: Antifungal efficacy of photochemical cross-linking (PACK-CXL) with 0.1% and 0.25% riboflavin was evaluated with a comparative in vitro study. METHODS: Candida albicans and Aspergillus fumigatus ATCC reference strains, Candida parapsilosis, Aspergillus fumigatus, Fusarium solani, Scedosporium apiospermum, and Alternaria alternata strains isolated from keratitis cases were chosen as targeted microorganisms. Unique "black plate method" was developed in polystyrene microplates. Riboflavin suspensions in 0.1% and 0.25% were separately added into inoculated wells. Non-inoculated wells were filled by black colored dye in order to protect treated wells from reflection of UV treatment. After ultraviolet A (UVA) treatment, each well was evaluated by microbiological culture in order to count viable fungal colonies. Fungal killing rate was calculated by comparing fungal counts (CFU/mL) before and after UVA application of riboflavin-added wells. RESULTS: Four different fungal inoculum concentrations of targeted microorganisms, including 104, 103, 102, and 101 CFU/mL, were assayed. PACK-CXL with 0.25% riboflavin was found to be highly effective on fungal cells even in 104 CFU/mL of concentration. CONCLUSIONS: PACK-CXL appears as a promising treatment option for difficult-to-treat cases of fungal keratitis and 0.25% riboflavin concentration increases fungicidal effect of the procedure dramatically.
PURPOSE: Antifungal efficacy of photochemical cross-linking (PACK-CXL) with 0.1% and 0.25% riboflavin was evaluated with a comparative in vitro study. METHODS:Candida albicans and Aspergillus fumigatus ATCC reference strains, Candida parapsilosis, Aspergillus fumigatus, Fusarium solani, Scedosporium apiospermum, and Alternaria alternata strains isolated from keratitis cases were chosen as targeted microorganisms. Unique "black plate method" was developed in polystyrene microplates. Riboflavin suspensions in 0.1% and 0.25% were separately added into inoculated wells. Non-inoculated wells were filled by black colored dye in order to protect treated wells from reflection of UV treatment. After ultraviolet A (UVA) treatment, each well was evaluated by microbiological culture in order to count viable fungal colonies. Fungal killing rate was calculated by comparing fungal counts (CFU/mL) before and after UVA application of riboflavin-added wells. RESULTS: Four different fungal inoculum concentrations of targeted microorganisms, including 104, 103, 102, and 101 CFU/mL, were assayed. PACK-CXL with 0.25% riboflavin was found to be highly effective on fungal cells even in 104 CFU/mL of concentration. CONCLUSIONS: PACK-CXL appears as a promising treatment option for difficult-to-treat cases of fungal keratitis and 0.25% riboflavin concentration increases fungicidal effect of the procedure dramatically.
Entities:
Keywords:
0.1% and 0.25% riboflavin; antifungal efficacy; black plate method; photochemical cross-linking (PACK-CXL)