Evaluating the in vitro efficacy of gatifloxacin, levofloxacin and gentamicin against Acanthamoeba cysts.

Abstract

To evaluate the in vitro efficacy of three commercial ophthalmic solutions (gatifloxacin, levofloxacin and gentamicin) against cysts of Acanthamoeba species. Experimental study METHODS: Acanthamoeba cysts belonging to genotypes T3, T4 and T5 were incubated with three ophthalmic solutions for different periods of time; 1, 24, 48 and 72h at 37°C. After incubation, treated cysts were stained with trypan blue and counted to express the percent of growth inhibition. Additionally, the viability of treated cysts was assessed by culturing them in PYG medium at 30°C for 72h as well as on non-nutrient agar plates at 30°C for 1month. Acanthamoeba cysts of all genotypes were susceptible to gentamicin and gatifloxacin after exposure for 1h and 24h, respectively, and for levofloxacin, cysts of all genotypes were resistant to levofloxacin even after 72h of incubation. Gentamicin and gatifloxacin showed statistically highly significant difference (P < 0.001), and levofloxacin showed statistically significant difference (P < 0.05) in comparison to non-treated control. Gentamicin and gatifloxacin were highly effective against Acanthamoeba cysts. Although our results should be confirmed in animal models, this result will guide the choice of the appropriate ophthalmic drugs for early treatment of eye infection caused by Acanthamoeba spp.