2022 OMIG Abstracts

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Evaluation of Rose Bengal, Erythrosin B, and Eosin Y for Photodynamic Antimicrobial Therapy Against Ocular Isolates

Katherine D. Leviste1, Paula A. Sepulveda-Beltran1, Heather Durkee1, Maya Jarolem2, Rebecca Menendez1, Braulio Ferreira3,
Roger Leblanc3, Jean-Marie Parel1,4, Guillermo Amescua1,4, Darlene Miller4,5
1Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida; 2College of Human Ecology, Cornell University, Ithaca, New York; 3Department of Chemistry, College of Arts and Science, University of Miami, Coral Gables, Florida; 4Anne Bates Leach Eye Hospital, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida; 5Ocular Microbiology Laboratory, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida

Purpose: To compare the in vitro inhibitory effect of three different photosensitizers, Rose Bengal (RB), Eosin Y (EY), and Erythrosin B (EB), using photodynamic antimicrobial therapy (PDAT) on ocular Pseudomonas aeruginosa and Candida albicans isolates.

Methods: Solutions of each of the three photosensitizers (RB, EB, and EY) were prepared at 0.1% concentration in 0.9% sodium chloride (NaCl). Clinical isolates of Pseudomonas aeruginosa (PA) and Candida albicans (CA) were tested in this study. Candida albicans isolates were prepared in solution to 1.5 × 104 CFU/mL and Pseudomonas aeruginosa isolates were prepared in solution to 1.5 × 107 CFU/mL. For each combination of photosensitizer and microbial organism suspension, the following treatment groups were assigned: (1) Control (No photosensitizer/ No Irradiation); (2) Photosensitizer/No Irradiation; (3) Photosensitizer/Irradiation. All photosensitizers are activated by the same wavelength of light and all plates in Group 3 were irradiated with a custom green-light source for total fluence of 5.4 J/cm2. Plates were protected from light, incubated at 37oC for 72 hours, and then photographed. Percent inhibition was evaluated using Labview-based software.

Results: Pseudomonas aeruginosa isolates mixed with 0.1% RB with and without irradiation demonstrated minimal microbial inhibition. Pseudomonas aeruginosa isolates mixed with 0.1% EY and EB demonstrated no microbial inhibition in either the dark or irradiated groups. Candida albicans isolates mixed with 0.1% RB, EY, and EB with and without irradiation demonstrated 2-log microbial reduction.

Conclusions: RB photosensitizers may confer more antimicrobial inhibition on Pseudomonas aeruginosa than EB and EY photosensitizers. RB, EB, and EY have inhibitory effect on Candida albicans isolates. More studies are needed to evaluate the strain-specific inhibitory effect on ocular isolates. PDAT with RB, EB, and EY may be an effective adjunct treatment for some common ocular pathogens known to contribute to infectious keratitis.

Disclosure: N: (Leviste, Sepulveda-Beltran, Jarolem, Menendez, Ferreira, Leblanc);
P: (Durkee, Parel, Amescua, Miller)

Support: Supported by the Edward D. and Janet K. Robson Foundation (Tulsa, OK); the Florida Lions Eye Bank and the Beauty of Sight Foundation (Miami, FL); NIH Center Core Grant P30EY14801; Research to Prevent Blindness – Unrestricted Grant; and the Henri and Flore Lesieur Foundation (Chicago, IL) (Parel).

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