INTERDISCIPLINARY LABORATORY TRIALS FOR ISOLATION AND CHARACTERIZATION OF PATHOGENIC FREE-LIVING AMOEBAE FROM THE EGYPTIAN ENVIRONMENT

Abstract

Free-living amoebae species, such as Acanthamoeba and Vermamoeba vermiformis are found worldwide and cause severe infections in humans. It is critical to employ a variety of media in order to maximize the recovery of FLA from environmental samples. Interestingly, greater variety of media enhances the chances of detection of FLA. Thus, for research of amoebae diversity and ecology, it is critical to identify the efficacy of various media in order to choose from a small number of the most appropriate. In the present study, inlet and outlet water samples (n = 96) were collected from conventional and compact drinking water treatment facilities (DWTFs), concentrated through nitrocellulose membrane filters (0.45µm pore size) and cultured on non-nutrient agar covered with dead Escherichia coli. The morphologically positive Acanthamoeba and Vermamoeba, and Naegleria isolates were subjected to molecular identification and 19 morphologically different Acanthamoeba, two Vermamoeba, and one Naegleria isolates were genotyped for further confirmation. The predominance of FLA in surface water samples was belonging to Acanthamoeba (68.8%). Naegleria was observed only in one sample collected from the inlet of conventional DWTF. All morphologically positive samples for Acanthamoeba proved to be positive by PCR. The conventional DWTF showed better results (66.7%) for removing Acanthamoeba and Vermamoeba vermiformis than the compact DWTF (50%). At the sequence level, three Acanthamoeba genotypes (T3, T4, and T15) and two Acanthamoeba species (i.e., Acanthamoeba lenticulata