Characterization of Entamoeba histolytica and Entamoeba dispar in fresh stool by PCR
Gastroenterology and Hepatology from Bed to Bench,
Vol. 3 No. 1 (2010),
12 December 2009
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
- locus D-A
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