Occurrence of Acanthamoeba Genotypes in Wastewater Samples in Tehran, Iran

Background Acanthamoeba spp. is potentially pathogenic free-living amoeba that can exist in various water sources. The presence of this amoeba in water sources could be a health hazard as Acanthamoeba could lead to severe diseases such as Acanthamoeba keratitis and encephalitis. This study aimed to determine the genotypes of isolated Acanthamoeba spp. in raw wastewater samples in Tehran, Iran. Methods Overall, 90 raw wastewater samples were collected from water treatment facilities in west and south of Tehran, Iran during 2014-2016. Water samples were filtered and cultured on non-nutrient agar (NNA) medium enriched with Escherichia coli. Morphological and molecular analyses were done on positive strains. The pathogenic ability of the isolated strains was determined using physical assays. Results Totally, 6 out of 90 (6.7%) samples were positive for Acanthamoeba, according to morphological characteristics of double-walled cysts. Genotyping and sequencing of the positive strains showed Acanthamoeba belonging to T4 (83%) and T11 (17%) genotypes. In vitro pathogenicity tests were revealed that five isolates were classified as non-pathogenic strains and one strain belonging to T4 genotype was classified as the highly pathogenic amoebae. Conclusion The current research reflected a low contamination of wastewater sources to Acanthamoeba. More studies regarding the contamination of wastewaters before and after treatment are required in different places of the country.