The effects of freezing and antibiotics on the viability of Acanthamoeba cysts.

The effects of cryotherapy and antibiotics (paromomycin, neomycin, or propamidine isethionate) on the viability of Acanthamoeba polyphaga and Acanthamoeba castellani cysts were studied in vitro. Either cryotherapy or exposure to antibiotic led to a decrease in the number of viable A castellani detected; A polyphaga showed variable response to the antibiotics tested. The combination of cryotherapy and antibiotic therapy was more cysticidal than either modality alone and eliminated detectable viable organisms in five of six experiments. Of the antibiotic solutions tested, paromomycin (15 mg/mL) was the most effective.