Comparison of three different methods for concentration and purification of giardia lamblia cysts

Background: Giardia lamblia is the most frequent human intestinal protozoan worldwide. Diagnosis of G. lamblia by microscopic examination of stool is common, but ELISA & IFA methods have been used in research and epidemiological studies recently. To produce polyclonal antibodies for designing ELISA & IFA kites molecular and genomic studies (PCR and parasitic culture) as well as other epidemiological purposes, purification of parasite cysts is required. Different methods were designed for this reason. A method, which can save the safe cysts without debris and other contamination, is required. In this study we decided to purify cysts from positive specimens with known methods and compare them on the basis of purification grade. Material and methods: three different methods were used for purification of cysts from positive samples (sucrose one stage, sucrose- percoll, and sucrose two stage gradients). The resulting product of these methods compared on the basis of elimination of debris, cysts purification grade and recovered cyst by using direct examination and Neobar chamber counting. Results: Cyst solutions from first and second methods were contained debris and cellulose. In third method approximately all of bacteria were eliminated and cysts obtained safely but cysts recovery rate was low (3×104 per 2gr of stool). Conclusion: third method (sucrose two stage gradients) was better than two other for isolation and purification of parasitic cysts and debris was less it seems designing a new simple method is highly needed for better elimination the debris and higher recovery rate of cysts.