Microscopic Study and Differentiation of Entamoeba Histolytica from Entamoeba Dispar by Polymerase Chain Reaction in Medical Centers of Zahedan

Background : Entamoeba histolytica, resident in large bowel, is the causative agent of an estimated 40 to 50 million cases of amebic colitis and liver abscess, and is responsible for up to 100000 deaths world wide each year. Based on the results of various studies, it is accepted that Entamoeba histolytica and Entamoeba dispar which are morphologicaly identical, differ in biology and pathogenicity. This study was performed to estimate the prevalence of contamination of stool samples with these species in medical centers of Zahedan city.

  Materials and Methods: In this descriptive study we used microscopy, Formalin-ether concentration, culture and PCR techniques to differentiate of Entamoeba histolytica from Entamoeba dispar in 1562 stool samples in medical center of Zahedan during July 2004 to January 2006. Data were analyzed with Chi-square, Mann-Whitney and Fisher tests. P value<0.05 considered to be statistically significant.

  Results: Eight cases (0.51%) of all samples were positive for Entamoeba histolytica/ Entamoeba dispar by direct microscopy and Formalin-ether concentration Methods. All isolates were cultured in HSr+s and Robinson Media. Seven samples were examined by 2 set of oligonucleotid primers HSP _1,2 and DSP_1,2 by PCR technique and six isolates were identified to be Entamoeba dispar.

  Conclusion: This study by using PCR technique showed that most of the patients referred to medical centers of Zahedan were infected with Entamoeba dispar.