title: Resistance of Acanthamoeba castellanii cysts to physical, chemical, and radiological conditions.
abstract: Resistance of Acanthamoeba castellanii cysts to disinfection agents, antimicrobial agents, heat, freeze-thawing, ultraviolet radiation (UV), gamma irradiation, and cellulase were evaluated in vitro. Following exposure to different agents, the cysts were removed and cultured for A. castellanii trophozoites for 3-14 days. Solutions containing 20% isopropyl alcohol or 10% formalin effectively killed A. castellanii cysts. Hydrogen peroxide (3%, AOSept Disinfectant) effectively killed A. castellanii cysts after 4 hr of exposure. Polyhexamethylene biguanide (0.02%), clotrimazole (0.1%), or propamidine isethionate (Brolene) were effective in killing A. castellanii cysts in vitro. Acanthamoeba castellanii cysts were resistant to both 250 K rads of gamma irradiation and 800 mJ/cm2 of UV irradiation. Excystment of trophozoites was accelerated after exposure to 10, 100, and, 1,000 units of cellulase. These results suggest that A. castellanii cysts benefit by enhanced survival because of their resistance to very harsh environmental conditions.
authors.affiliation: Department of Microbiology and Clinical Microbiology, Istanbul Faculty of Medicine, University of Istanbul, Capa, Turkey.
authors.forename: A
authors.initials: A
authors.lastname: Aksozek
authors.forename: K
authors.initials: K
authors.lastname: McClellan
authors.forename: K
authors.initials: K
authors.lastname: Howard
authors.forename: J Y
authors.initials: JY
authors.lastname: Niederkorn
authors.forename: H
authors.initials: H
authors.lastname: Alizadeh
mesh_terms: D019840:2-Propanol / Q000494:pharmacology; D000048:Acanthamoeba / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002480:Cellulase; D004202:Disinfectants / Q000494:pharmacology*; D005557:Formaldehyde / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004202:Disinfectants; D005557:Formaldehyde; D006861:Hydrogen Peroxide; D002480:Cellulase; D019840:2-Propanol