Background: Water contamination with variable microbial contaminants is a major problem worldwide.
Acanthamoeba spp. are able to survive in different environments including various water sources, thus
posing important public health hazards.
Objective: To investigate the presence of Acanthamoeba spp. in three drinking water treatment plants
(DWTPs) in Menofia governorate.
Material and Methods: Overall, 72 water samples were collected from three DWTP located in Shebin El-
Kom, Tala, and El-Shohadaa cities. Water samples were collected monthly from the inlet and the outlet of
each DWTP during the period from September 2021 to August 2022. Samples were filtered and processed
for detection of Acanthamoeba spp. using direct microscopic examination, Gimenez stain, cultivation on
non-nutrient agar (NNA), as well as molecular and phylogenetic analyses. Acanthamoeba isolates were
microscopically identified to the genus level based on morphological criteria while molecular confirmation
was accomplished by sequencing of the positive-PCR products, and phylogenetic analysis.
Results: Acanthamoeba was detected in 22 water samples (30.6%) by cultivation on NNA, out of which 17
were from raw water, and 5 from treated water samples. The highest detection rate of Acanthamoeba spp.
was in Tala DWTP (11/22) followed by El-Shohadaa DWTPs (6/22), and Shebin El-kom DWTP (5/22).
Seasonal distribution of Acanthamoeba isolates was highest in summer (40.8%) while the lowest was
in winter (13.7%). Morphological identification revealed six Acanthamoeba spp. namely, A. triangularis,
A. polyphaga, A. astronyxis, A. castellanii, A. royreba and A. quina. Utilizing phylogenetic analysis, only 9
samples (12.5%) were identified, all of which belonged to genotype T4.
Conclusion: Identification of Acanthamoeba spp. (genotype T4) in municipal water represents a potential
health risk which should alert the authorities to adjust the procedures used to control this waterborne
pathogen.