Genetic Characteristics of Echinococcus granulosus from Fixed Paraffin-Embedded Tissue Samples in Human Isolates Based on the High-Resolution Melting Point Analysis in Sabzevar, Northeast Iran.

Background: There are ten genotypes of Echinococcus granulosus with different intermediate and final hosts affecting the parasite's life cycle and its transmission to humans. Therefore, this study was conducted to determine the genotype of isolated hydatid cysts using the simple and fast high-resolution melting point analysis (HRM) method.

Methods: The paraffin tissue samples of patients who underwent surgery were obtained from the pathology sample bank of Vasei and Emdad Hospitals in Sabzevar, Iran during 2010-2020. The DNA content of the samples was extracted after collecting and determining the characteristics using the DNA extraction kit. PCR was performed on the samples and the presence of the hydatid cyst genome was confirmed using the special Master Kit. Mix PCR of Solis Biodyne Company and Real-Time device (Bio-Rad) were used, and the genetic identity of hydatid cysts were determined.

Results: Out of 33 paraffin samples, 21 samples contained hydatid cyst DNA, two of which were from the brain and 19 from the liver tissues; 12 samples did not contain hydatid cyst DNAs. All liver samples were from sheep species (G1), and the brain samples were from buffalo species (G3). Therefore, 9.53% of the Echinococcus species collected were buffalo (G3), and 90.47% were sheep (G1) strain.

Conclusion: Based on previous patterns, HRM methods can be used for easy and quick identification of Echinococcus strains. The G1 strain was the dominant strain causing hydatid cyst in different human organs, including the liver and brain.