Blastocystis is an anaerobic parasite that was identified as the most common eukaryotic organism
reported in human fecal samples. Data on treatment options signifies that efficacious antimicrobial
eradication of Blastocystis spp. is still far from straight forward. As well as Metronidazole, has
shown some resistance. The study evaluated chitosan and chitosan Nano particles against Blastocystis
in vitro. Blastocystis species in stool samples were cultured. Culture tubes were divided into
three groups: Chitosan, Chitosan Nano particles and Metronidazole (reference drug), and positive
control. Different criteria were used to evaluate the tested drugs on Blastocystis and assessing
the viability before and after treatment by the use of Neutral red stain and recording structural
changes. Also, TEMand the single cell gel electrophoresis (SCGE)/comet assay were used.
The results showed a direct relation between increase in the concentration of Chitosan and Chitosan
nano-particles and exposure time and increase in the mortality rates. TEM showed morphological
damage when exposed to tested drug, Comet assay showed direct relationship between the
increase in the dose of Chitosan Nano particles NPs and the degree of DNA genotoxic destruction.