Evaluation of in vitro effects of selected physical and chemical agents on detected in Poland Acanthamoeba strains – factors of increasing threats for public health

Abstract

Acanthamoeba keratitis, the vision-threatening corneal disease reported with increasing frequency in Poland is difficult to treat due to extremely high resistance of the amoeba cysts to chemicals. The agents of possible anti-amoebic activity are still tested. Pathogenic Acanthamoeba samples/isolates acquired from severe cases of keratitis examined by molecular techniques to determine genotypes, compared to one another as well as to the environmental Acanthamoeba castellanii Neff strain were included in the studies. These strains were in vitro examined in terms of their sensitivity/resistance to selected chemicals and tolerance to temperature changes. Samples of the strains cultivated in vitro under bacteria-free conditions were monitored during different growth phases. Higher amoebic population dynamics was observed in both pathogenic Acanthamoeba strains during transfer to 37°C. Agents tested influenced population dynamics in different degree; they showed amoebostatic or amoebicidal effects, however a tendency toward induction of encystment also appeared. Because activation of the dormant cysts can lead to repeated development of amoebae, very important is cysticidal efficacy of chemicals. Further in vitro investigations on various Acanthamoeba strains with different chemicals are still necessary.