Assessing Different Methods of DNA Extraction from Giardia Lamblia Cysts

Background and Giardia lamblia (G.lamblia) is one of flagellated protozoan pathogens. Giardiasis is the most common human parasite infection in the world, causing a lengthy course of diarrhea. The aim of the present study was to compare five different methods of DNA extraction from G.Lamblia cyst and determining the most efficient DNA extraction method. This study was carried out in 30 human fecal samples with Giardia infection. To diagnose giardiasis wet mount from feces and staining with Lougol’s stain were performed. The cysts were purified and concentrated in a sucrose gradient. The isolated DNA from cysts was performed using different methods including freeze-thaw cycles, glass beads, and stool DNA extraction Kit (Accu prep); freeze-thaw cycles and Pheol-Cholorform-Isoamil alcohol (PCI); boiling and PCI; sonication and PCI; freeze-thaw and high salt. Then the gdh gene was amplified through single round PCR method. The highest and lowest mean of OD were found in FGK and High salts, respectively. The highest and lowest means of concentration were seen in the freeze-thaw cycles and PCI and the FGK methods, respectively. Moreover, after using the FGK bands of PCR no smears were observed. Also, the lowest time of extraction was detected in FGK method. To remove problems of DNA extraction and decreasing the time of extraction, glass beads along with Accu prep stool DNA extraction Kit (Bioneer) could be suitable and the most efficient method.