Frequency and Genotyping of Acanthamoeba Species in the Swimming Pools and Ponds of Khoramabad, Iran, in 2016

Acanthamoeba is a free-living and opportunistic amoeba found in the water, soil, and air. This amoeba causes granulomatous amoebic encephalitis in the immunocompromised patients and amoebic keratitis in the people using contact lenses. The genotypes of Acanthamoeba are pathogenic and non-pathogenic. Regarding this, the present study aimed to determine the frequency and genotypes of Acanthamoeba in the water pools and ponds of Khorramabad, Iran, using culture, polymerase chain reaction (PCR), and sequencing methods in 2016.
This study was conducted on a total of 84 water samples collected from the water pools and ponds of Khorramabad. The samples were filtered using nitrocellulose syringe (0.45 μm); subsequently, they were cultured on 1.5% non-nutrient agar, covered by killed Escherichia coli and incubated at 27ºC. After the extraction of DNA from positive samples, PCR was performed using specific primers to detect and confirm Acanthamoeba. Then, for genotyping, the PCR products of positive samples were sequenced.
Out of the 84 water samples, 50 (59.5%) cases were positive for amoeba in the culture method. However, the results of the PCR revealed 35 (41.7%) positive samples for Acanthamoeba. The sequencing of the PCR products demonstrated that 17 samples were T4 genotype (pathogen), and the rest were other Acanthamoeba genotypes.
This study indicated the high prevalence of Acanthamoeba species, especially the pathogenic type, in the water pools of Khoramabad that could be a source of infection risk for humans. Regarding the fact that almost half of the found genotypes were pathogenic (genotype T4) that are the main cause of amoebic keratitis, these water bodies could be a potential risk factor for the public health. Therefore, the health professionals should prevent contamination.