Specific detection of Entamoeba histolytica DNA by hemolysin gene targetedPCR

Diagnostic differentiation of pathogenic Entamoeba histolytica from non-pat hogenic Entamoeba dispar is of great clinical importance. We have developed and evaluated a new polymerase chain reaction (PCR) assay (haemo-PCR) base d on the novel E. histolytica hemolysin gene HLY6. The specificity of this assay was confirmed by analyzing different Entamoeba species, faeces sample s, human and bacterial DNA, and digestion of amplification products with ap propriate restriction enzymes. The sensitivity was confirmed by serial dilu tions of E. histolytica HM-1:IMSS DNA in the excess of human DNA. Totally, 45 clinical samples were analyzed by the haemo-PCR assay including amoebic liver abscess (ALA) fluids from 23 patients suspected for amoebiasis. four faeces samples containing E. histolytica and E. dispar, and positive and ne gative controls. The results were compared with those obtained with PCRs fo r cystein-rich surface protein (P30) and small subunit ribosomal RNA (ssu r RNA) genes. The haemo-PCR gave a positive result in 18 (89%) ALA fluids com pared with 14 (77%) and five (28%,) by PCR for p30, and ssu rRNA, respectiv ely. PCR products were obtained only from specimens containing E. histolyti ca DNA. The haemo-PCR assay was therefore found to be a valuable diagnostic tool for identification of E. histolytica infections both in faeces and AL A samples. (C) 2001 Elsevier Science B.V. All rights reserved.