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Characterization of Entamoeba histolytica and Entamoeba dispar in fresh stool by PCR

Ehsan Nazemalhosseini Mojarad, Zahra Nochi, Navid Sahebekhtiari, Mohammad Rostami Nejad, Hossein Dabiri, Ali Haghighi




Aim: The aim of this study was to differentiate Entamoeba dispar from Entamoeba histolytica by PCR directly from fresh stool.

Background: Microscopy does not allow for the differentiation of Entamoeba dispar from Entamoeba histolytica. Several PCR-based methods have been described and used successfully for this purpose, but the methods for DNA extraction from stool samples are usually time-consuming and problematic due to inhibitory factors in feces.  

Patients and methods: From a total of 1700 stool samples collected and examined by microscopy, 22 samples (1.3%) were microscopically positive for the E. histolytica /E. dispar complex. The DNA of these samples was extracted directly from fresh stool and PCR was carried out using two sets of species-specific primers from a short tandem repeat (STR) in the D-A locus.

Results: Of these, 21 samples (95.45%) were diagnosed as E. dispar and only one sample (4.55 %) was found to be E. histolytica. In this study, by improving the DNA extraction from fresh stool, we were able to efficiently differentiate E. histolytica and E. dispar.

Conclusion: To avoid unnecessary treatment of patients not infected with E. histolytica, the development of effective techniques, such as direct DNA extraction from stool, is recommended.


Entamoeba histolytica; Entamoeba dispar; fresh stool; PCR; locus D-A

DOI: https://doi.org/10.22037/ghfbb.v3i1.68