Pathogenicity, morphology, and differentiation of Acanthamoeba

Acanthamoeba keratitis is sight threatening corneal infection caused by pat hogenic Acanthamoeba. Previous studies have shown the genotypic differences between pathogenic and non-pathogenic species/strains of Acanthamoeba. In this study, we examined the morphological differences between pathogenic an d non-pathogenic species/strains using scanning electron microscopy. Pathog enic Acanthamoeba exhibited higher number of acanthopodia (structures assoc iated with the binding of amoeba to the target cells) as compared to non-pa thogens. In addition, interactions of amoeba with the corneal epithelial ce lls were studied. Only pathogenic amoeba exhibited adhesion to epithelial c ells. Further results indicated that phagocytosis occurs in the pathogenic amoeba by the formation of amoebastome (characteristic of amoeba phagocyte) . This study showed that Acanthamoeba phagocytosis may be both an efficient means of obtaining nutrients for the amoeba and a significant factor in th e pathogenesis of Acanthamoeba infections.