Selective identification of the pathogenic E. histolytica in fresh stool samples using polymerase chain reaction (PCR).

Stool samples from 93 individuals clinically presumed to have intestinal amoebiasis and subjected to microscopic examination and DNA extraction. The PCR amplification was performed using two sets of primers that differentiate between pathogenic and nonpathogenic Entamoeba DNA. Of 93 clinically positive cases, 51 (54.8%) were positive by microscopy, while 53 (56.9%) were detected by PCR as having DNA specific for either E. histolytica / E. dispar. A specificity of 85.71% and a sensitivity of 92.15% were with PCR compared to microscopy. Among 53 PCR positive specimens, three different DNA sequences were demonstrated: 8 specimens had DNA sequences specific of E. histolytica, 31 with DNA specific for E. dispar and 14 specimens have mixed DNA sequences for E. histolytica and E. dispar. PCR is a sensitive and a specific tool. PCR application is better the epidemiology in endemic areas through keeping indefinite DNA records for prospective and retrospective studies.