Volume 50/Number 1/Abstract 3
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Acta Parasitologica, Vol.50, No. 1, 2005, 25-31
Lidia Chomicz(1)*, Justyna Zebrowska(1), Janusz Piekarczyk(2), Bohdan Starosciak(3), Przemyslaw Myjak(4), Michal Walski(5) and Zygmunt Kazimierczuk(6,7) - In vitro studies on susceptibility of Acanthamoeba castellanii to selected chemical agents

(1)Department of Medical Biology, Medical University of Warsaw, 73 Nowogrodzka Street, 02-018 Warsaw; (2)2nd Department of Maxillofacial Surgery, Medical University of Warsaw, 4 Lindleya Street, 02-005 Warsaw; (3)Department of Pharmaceutical Microbiology, Medical University of Warsaw, 3 Oczki Street, 02-007 Warsaw; (4)Department of Tropical Parasitology, Medical University of Gdansk, 9b Powstania Styczniowego Street, 81-516 Gdynia; (5)Ultrastructure Laboratory of CNS, Medical Research Centre, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106 Warsaw; (6)Institute of Chemistry, Agricultural University, 159c Nowoursynowska Street, 02-787 Warsaw; (7)Laboratory of Experimental Pharmacology, Polish Academy of Sciences, Medical Research Center, 5 Pawinskiego Street, 02-106 Warsaw; Poland
*Corresponding author: lchomicz@ib.amwaw.edu.pl

Amoebae of the Acanthamoeba castellanii Neff strain, cultured in bacteria-free condition at room temperature, were tested in vitro for their susceptibility to selected chemical compounds. The amoebae, grown during 4 and 10 days following regular subculturing, were exposed for 24 h to three compounds: the newly synthesized imidazole derivatives (1) 2-methyl-3N-(4-nitrobenzyl)- 5-nitro-1H-imidazole designated as AG16; (2) 2-methyl-3N-(3,5-dinitrobenzyl)-5-nitro-1H-imidazole designated as AG17 and to the (3) cationic antiseptic agent chlorhexidine digluconate (CHX). Two different concentrations of the above-mentioned substances were applied. The results showed that all chemicals tested had some amoebicidal effect on 4-day grown population of Acanthamoeba; variations in susceptibility of the amoebae, depending on the kind and concentration of the compounds occurred. It was also observed that several agents changed the relationship between A. castellanii trophozoites and cysts. Chlorhexidine digluconate caused a decrease in percentage of the trophozoites to 88.4% at higher concentration of the compound, 10 ug/ml (in comparison to 97.8% from the control samples), however, significant increase of the cyst percentage, to 11.6% in assays with this concentration of chlorhexidine were revealed (2.2% in the control samples). Tendency toward induction of encystment was also apparent when AG17 was applied. Because activation of the dormant cysts can lead to repeated development of amoebae, very important is cysticidal efficacy of tested agents. Among all compounds examined by us, the newly synthesized imidazole derivative AG16 was the most effective. It was expressed as decrease in average number of amoebae (to 655.6 103/ml at concentration of the agent 8 ug/ml; 682.5 103/ml in assays with CHX at concentration 4 ug/ml; 893 103/ml in the control samples) connected with a clear cysticidal effect (1.4% of cysts at concentration 4 ug/ml of AG16).

KEY WORDS: Acanthamoeba castellanii, Protozoa, susceptibility to chemicals, ultrastructure

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