Study of Entamoeba Histolytica from Stool Using Polymerase Chain Reaction Amplification

Entamoeba histolytica infection is the third-greatest parasitic disease responsible for death in the world. Amoebic infections result either in a harmless colonization of the intestine, or in an amoebiosis with invasion and damage of the intestine, liver, lung, and brain. These distinct manifestations are due to the existence of Entamoeba histolytica alone or with Entamoeba dispar as a complex of two different, but morphologically identical species. One that is a nonpathogenic commensal in the intestine of humans, E. dispar , and the other that is capable of inducing cell and tissue damage. Due to genomic DNA differences between pathogenic and nonpathogenic of these protozoan infections, we used a polymerase chain reaction (PCR) method that diagnosed and differentiated the two conditions. We report here a DNA extraction protocol using non-fixed stool samples. We characterized 60 of 65 stool specimens from patients with amoebiosis. Among them, 45 (75%) were infected only with the nonpathogenic species, E. dispar, while 15 (25%) displayed a mixed infection with both the pathogenic nonpathogenic species ,ie , E. dispar and E. histolytica. The PCR protocol showed a specificity of 1.00 and a sensitivity of 0.95. The molecular approach is therefore reliable and applicable in the identification of pathogenic E.histolytica infection. Our results provide important data for the Iraqi Health Care System and a need to address the emerging problem of amoebic infection in Iraqi.