Isolation and identification of pathogenic Acanthamoeba species from different water sources in Minia Governorate, Egypt

Abstract

Acanthamoeba species (spp.) are opportunistic pathogens and they are a member of free-living amoebae (FLA). They cause granulomatous amoebic encephalitis (GAE), a chronic disease of immunocompromised hosts such as acquired immune-deficiency syndrome (AIDS) patients and transplant recipients. The present study was conducted to isolate and to identify Acanthamoeba spp. from various water sources. During the study period, 150 water samples were collected from various sources such as streams and ponds, tap water, tanks, swimming pools and Nile River water. All samples were processed and cultured on non-nutrient agar medium (NNA) with Escherichia coli overlay for the isolation of Acanthamoeba spp. Organism identifying was based on the microscopic morphology of cyst and trophozoites forms. Confirmation PCR was done to positive culture samples. The pathogenicity of Acanthamoeba spp. was analyzed by thermo-tolerance assay. Acanthamoeba spp. were detected in 84 (56%) out of the 150 examined water samples. The highest percentage of Acanthamoeba presence was observed in streams and ponds water (70.73%), followed by swimming pools water samples (60%) and Nile River water samples (66.67%) and the lowest was in tap water samples (37.5%). Out of 84 water samples positive by NNA culture, 72 (85.71%) samples were positive by PCR using specific primers for Acanthamoeba spp. Based on pathogenicity test assays, among 84 positive cultures, 39 (46.43%) were thermo-tolerant. This study was showing the distribution of Acanthamoeba spp. in various water sources in the environment. Also, this study confirmed that the high presence of pathogenic strains in recreational water could threat contact lens wearers.