In vitro evaluation of the effectiveness of the macrolide rokitamycin and chlorpromazine against Acanthamoeba castellanii

The present study demonstrates the in vitro effectiveness of the macrolide rokitamycin and the phenothiazine compound chlorpromazine against Acanthamoeba castellanii. Growth curve evaluations revealed that both drugs inhibit trophozoite growth in dose- and time-dependent ways. The effects of both drugs when they were used at the MICs at which 100% of isolates are inhibited were amoebistatic, but at higher doses they were amoebicidal as well as cysticidal. Experiments showed that when rokitamycin was associated with chlorpromazine or amphotericin B, rokitamycin enhanced their activities. Furthermore, low doses of rokitamycin and chlorpromazine, alone or in combination, blocked the cytopathic effect of A. castellanii against WKD cells derived from the human cornea. These results may have important significance in the development of new anti-Acanthamoeba compounds.