Abstract
Purpose: :
In vitro recent studies have shown an antimicrobial effect of riboflavin and ultraviolet-A (UVA) collagen cross-linking (CXL) on a number of pathogens. In order to evaluate new therapies against severe acanthamoeba infections, we performed in vitro tests to assess the amoebicidal effects of riboflavin and ultraviolet collagen CXL.
Methods: :
Two different strains of Acanthamoeba spp were identically tested. Four treatment groups were considered: GROUP 1 (Control): no riboflavin, no UVA exposition. GROUP 2: 0.1% riboflavin, no UVA exposition. GROUP 3: 0.1% riboflavin, 30-minute UVA irradiation. GROUP 4: 0.1% riboflavin, 60-minute UVA irradiation. UVA application was performed with the parameters used for in vivo corneal collagen cross-linking (3 mW/cm2, 370 nm), and the diameter of application in all cases exceeded the limits of seeding of protozoa.
Results: :
In all the cases, cysts and trophozoites were detected at a distance from the application point greater than 5 mm, indicating that the amoebas were viable. The distance was similar for all treatments and control (14-15 mm), although it was slightly lower for CLX + riboflavin for 60 min (12 mm). The final morphology of trophozoites of the control and the treated amoeba was similar.
Conclusions: :
The negative results obtained in our study show that CXL is not an effective procedure against Acanthamoeba. However, in vitro results do not always reproduce in vivo efficacy, so future studies are needed to test the validity of this treatment for Acanthamoeba Keratitis.
Keywords: Acanthamoeba • microbial pathogenesis: experimental studies • radiation damage: light/UV