Effect of topical 0.5% povidone-iodine compared to 5% natamycin in fungal keratitis caused by Fusarium solani in a rabbit model: a pilot study

Abstract

Purpose:To evaluate the efficacy of topical administration of 0.5% povidone-iodine in experimental Fusarium solani keratitis in rabbits. Methods: Fungal keratitis caused by Fusarium solani was induced in the right eye of 24 New Zealand rabbits. The rabbits were randomly divided into 3 different treatment groups: Group I (povidone-iodine) -treated with topical 0.5% povidone-iodine; Group II (natamycin) -treated with topical 5% natamycin; and Group III (control) -treated with topical saline solution. In all groups the rabbits were treated for three days and then sacrificed. The corneas were excised, macerated and immersed in 10 mL BHI. Culture samples were plated daily on Sabouraud's agar for 7 days, and the number of colony-forming units (CFU) was counted. The rabbits were clinically evaluated during the treatment period. Results: The povidone-iodine and natamycin groups demonstrated better efficacy than the control group based on the number of rabbits with no colonies growing. However, there were no statistically significant differences between the three groups when the number of CFU was analyzed (p>0.05). Conclusion: Our study demonstrates important methodological considerations in the use of in vivo animal models for the testing of antifungal agents. Using this sample size and methodology of counting CFU, topical 0.5% povidone-iodine demonstrated no benefit in the treatment of experimental Fusarium solani when compared with topical 5% natamycin.ABSTRACT

Keratomycosis in a pet rabbit (Oryctolagus cuniculus) treated with topical 1% terbinafine ointment

“…This antiseptic, a complex of polyvinyl pyrrolidone and iodine, is reported to be efficacious against bacteria, viruses, and fungi. Its use has been advocated in the treatment of keratomycosis as an inexpensive, and widely available preparation, but is not sufficiently efficacious at concentrations of 0.5% and 1% …”

Antifúngicos em infecções oculares: drogas e vias de administração

“…In a number of cases, povidoneiodine 2.3% was used successfully to treat keratitis by Candida albicans and Acremonium strictum (132) . However, in a comparative study, povidone-iodine 0.5% showed no benefit compared to NTM 5% in the treatment of experimental keratitis by Fusarium solani (40) . In another experimental study, Fiscella et al showed that polyhexamethylene biguanide (PHBM) 0.02% is effective in the treatment of eye infections by Fusarium solani in rabbits (133) .…”

“…Epithelial debridement is recommended as an adjuvant therapy so that higher concentrations can be achieved in the corneal stroma. This provides a greater adherence of the drug to the de-epithelised surface (3,40) . However, in a study by Prajna et al epithelial scraping did not improve healing time.…”

Development of a capillary zone electrophoresis method to determine natamycin in food and a comparison with a liquid chromatography method

“…Natamycin has a certain effect in the treatment of bacterial and fungal keratitis, which is often used to prevent or treat fungal infections. [8][9][10][11][12] As a microbial preservative, natamycin is characterized in terms of safety, naturalness, and health, which has attracted much attention. 13 However, excessive intake of natamycin poses a potential threat to human health.…”