Effect of caspofungin on trophozoites and cysts of three species of Acanthamoeba.

OBJECTIVES Amoebic keratitis is difficult to treat, without total efficacy in some patients because of cysts that are less susceptible than trophozoites to the usual treatments. We investigated here the in vitro effectiveness of caspofungin, a new antifungal, against three species of Acanthamoeba. METHODS Trophozoites and cysts of Acanthamoeba castellanii, Acanthamoeba culbertsoni and Acanthamoeba polyphaga were incubated with caspofungin at concentrations varying from 16 to 500 mg/L. RESULTS The trophozoites of the three tested species were susceptible in vitro to caspofungin at a concentration of 250 mg/L (206 microM). Furthermore, this drug was cysticidal at a concentration of 500 mg/L (412 microM) against A. castellanii and A. culbertsoni. CONCLUSIONS Caspofungin could represent, if in vivo studies confirm its efficacy, a new anti-Acanthamoeba compound.