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. 2016 Apr;44(3):181-7.
doi: 10.1111/ceo.12644. Epub 2016 Feb 23.

Riboflavin and ultraviolet A as adjuvant treatment against Acanthamoeba cysts

Ricardo Lamy  1 , Elliot Chan  1 , Samuel D Good  1 , Vicky Cevallos  2 , Travis C Porco  2 , Jay M Stewart  1
Affiliations

Riboflavin and ultraviolet A as adjuvant treatment against Acanthamoeba cysts

Ricardo Lamy et al. Clin Exp Ophthalmol. 2016 Apr.

Abstract

Background: Experimental studies have shown that the standard dose of riboflavin (R) or R + ultraviolet-A (UVA) as solo treatment are not able to exterminate Acanthamoeba cysts or even trophozoites. The purpose of this study is to determine whether the application of R + UVA can enhance the cysticidal effects of cationic antiseptic agents in vitro.

Methods: The log of either polyhexamethylene biguanide or chlorhexidine minimal cysticidal concentration in solutions containing riboflavin (concentrations 0.1, 0.05 and 0.025%) plus either Acanthamoeba castellanii cysts or Acanthamoeba polyphaga cysts was determined and compared in groups treated with UVA 30 mW/cm(2) for 30 min and in control groups (with no exposure to UVA). A permutation test was used to determine the P value associated with treatment.

Results: Regardless of the riboflavin concentration and UVA treatment condition, no trophozoites were seen in plates where the cysts were previously exposed to cationic antiseptic agent concentrations ≥200 µg/mL for Acanthamoeba castellanii samples and ≥100 µg/mL for A. polyphaga samples. There was no statistical evidence that R + UVA treatment was associated with minimal cysticidal concentration (P = 0.82).

Conclusion: R + UVA in doses up to 10 times higher than recommended for corneal crosslinking does not enhance the cysticidal effect of either polyhexamethylene biguanide or chlorhexidine in vitro.

Keywords: Acanthamoeba; photochemotherapy; riboflavin; ultraviolet.

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Conflict of interest statement

Competing/conflicts of interest: None

References

    1. Khan NA. Acanthamoeba: biology and pathogenesis. Caister Academic Pr; 2009.
    1. Marciano-Cabral F, Cabral G. Acanthamoeba spp. as agents of disease in humans. Clin Microbiol Rev. 2003;16(2):273–307. - PMC - PubMed
    1. Qian Y, Meisler DM, Langston RHS, Jeng BH. Clinical experience with Acanthamoeba keratitis at the cole eye institute, 1999–2008. Cornea. 2010;29(9):1016. - PubMed
    1. Nagington J, Watson P, Playfair T, McGill J, Jones BR, Steele A. Amoebic infection of the eye. The Lancet. 1974;304(7896):1537–1540. - PubMed
    1. Visvesvara G, Jones DB, Robinson NM, et al. Isolation, identification, and biological characterization of Acanthamoeba polyphaga from a human eye. The American journal of tropical medicine and hygiene. 1975;24(5):784. - PubMed

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